May 1, 2017 | Author: Abhishek Kukreja | Category: N/A
®
NEPLAN
User’s Guide Electrical
Version 5
Busarello + Cott + Partner Inc.
ABB Utilities Gmbh
Bahnhofstrasse 40 CH-8703 Erlenbach Switzerland
Käfertalerstrasse 250 D-68167 Mannheim Germany
Phone: Fax: E-mail: Internet:
+49 621 386 27 86 +49 621 386 27 85
[email protected] www.abb.de/neplan
+41 1 914 36 66 +41 1 991 19 71
[email protected] www.neplan.ch
Contents
Contents TUTORIAL...............................................................................................................................1 INTRODUCTION ........................................................................................................................1 THE USER INTERFACE..............................................................................................................2 Toolbar ...............................................................................................................................2 Workspace ..........................................................................................................................3 Variant Manager ................................................................................................................3 Symbol Window ..................................................................................................................3 Message Window ................................................................................................................3 THE ONLINE HELP ...................................................................................................................4 DATA ORGANIZATION .............................................................................................................5 THE BASIC ELEMENTS OF NEPLAN........................................................................................6 Nodes ..................................................................................................................................6 Elements..............................................................................................................................7 Protection Devices, Current and Voltage Transformers....................................................7 Station.................................................................................................................................7 Symbol ................................................................................................................................8 Switches ..............................................................................................................................8 Zones and Areas .................................................................................................................8 Partial Networks.................................................................................................................8 STEP 1 – CREATE A NEW PROJECT .........................................................................................10 STEP 2 – ENTER A SMALL NETWORK......................................................................................12 Input data..........................................................................................................................12 Enter the network..............................................................................................................14 Test your network .............................................................................................................20 STEP 3 – INSERT HEADER, SAVE, PRINT, EXIT ......................................................................23 Insert Header ....................................................................................................................23 Save the network ...............................................................................................................25 Print the diagram..............................................................................................................26 Close and open projects ...................................................................................................27 STEP 4 – USE OF DIAGRAMS, LAYERS, AREAS AND ZONES ...................................................29 Use of Diagrams ...............................................................................................................29 Use of graphic layers........................................................................................................34 Define and assign Areas and Zones .................................................................................39 STEP 5 – CREATE AND USE LIBRARIES ...................................................................................47 Create a new Library........................................................................................................47 Import data from a library................................................................................................51 Update your network data with a library type .................................................................52 Export data to a library ....................................................................................................53 STEP 6 – DEFINE VARIANTS ...................................................................................................56 Insert new Subvariants .....................................................................................................57 Save modifications to the variants....................................................................................60 Create and assign a Topology Data File..........................................................................63 Create and assign a Load Data File ................................................................................66 NEPLAN User's Guide V5
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LOAD FLOW CALCULATION ...................................................................................................69 SHORT CIRCUIT CALCULATION..............................................................................................77 TRANSIENT STABILITY ANALYSIS .........................................................................................85 INTERFACES TO NEPLAN ...................................................................................................107 TIPS FROM THE PRACTICE ....................................................................................................109 Asymmetrical Network Structure....................................................................................109 Load Flow.......................................................................................................................109 MENU OPTIONS .....................................................................................................................1 FILE .........................................................................................................................................1 New .....................................................................................................................................1 Open ...................................................................................................................................1 Close ...................................................................................................................................1 Save.....................................................................................................................................1 Save As ...............................................................................................................................2 Print ... ................................................................................................................................2 Print Preview ... ..................................................................................................................2 Print Setup ... ......................................................................................................................2 Page Setup ... ......................................................................................................................2 Print on One Page ... ..........................................................................................................2 Import ... .............................................................................................................................2 Export ... .............................................................................................................................3 Exit......................................................................................................................................3 INSERT .....................................................................................................................................4 Edit Options........................................................................................................................4 Elements..............................................................................................................................5 AC-Line and Bus.................................................................................................................5 DC and Asym. Line/Bus......................................................................................................6 Nested Block .......................................................................................................................7 Link .....................................................................................................................................7 Map.....................................................................................................................................7 Calibration Symbol.............................................................................................................7 Header ................................................................................................................................8 Color Legend ......................................................................................................................8 Line Legend ........................................................................................................................8 Control Circuit ...................................................................................................................8 Function Block Menu..........................................................................................................9 EDIT.......................................................................................................................................10 Undo .................................................................................................................................10 Redo ..................................................................................................................................10 Cut ....................................................................................................................................10 Copy..................................................................................................................................10 Paste .................................................................................................................................10 Delete................................................................................................................................10 Data ..................................................................................................................................11 Graphics ...........................................................................................................................14 Search ...............................................................................................................................15 Statistics............................................................................................................................16 Diagram Properties ..........................................................................................................16 Variant Properties ............................................................................................................26 VIEW .....................................................................................................................................27 NEPLAN User's Guide V5
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Redraw..............................................................................................................................27 Variant Manager ..............................................................................................................27 Message Window ..............................................................................................................27 Symbol Window ................................................................................................................27 Ruler .................................................................................................................................27 Page Bounds .....................................................................................................................27 Grid...................................................................................................................................27 Snap to Grid......................................................................................................................28 Snape to Angle ..................................................................................................................28 Grid Properties.................................................................................................................28 Zoom Normal....................................................................................................................28 Zoom Percent....................................................................................................................28 Zoom Custom....................................................................................................................28 Zoom to Fit .......................................................................................................................28 Show Full Screen ..............................................................................................................29 ANALYSIS ..............................................................................................................................30 Calculation .......................................................................................................................30 Partial Network ................................................................................................................30 Parameter .........................................................................................................................31 Results...............................................................................................................................31 LIBRARIES .............................................................................................................................32 Libraries ...........................................................................................................................32 Symbol Library .................................................................................................................32 Set Active Library .............................................................................................................32 Copy to Diagram Library .................................................................................................32 Past from Diagram Library..............................................................................................32 Edit Diagram Library.......................................................................................................32 Import Old CCT Library...................................................................................................33 OPTIONS ................................................................................................................................34 Header ..............................................................................................................................34 Project Description...........................................................................................................34 Measurement and Size ......................................................................................................34 Calibrate...........................................................................................................................34 Insert Calibration Symbol ................................................................................................34 Make Backup ....................................................................................................................35 License ..............................................................................................................................35 WINDOW................................................................................................................................36 New Window .....................................................................................................................36 Cascade ............................................................................................................................36 Tile ....................................................................................................................................36 Arrange Icons ...................................................................................................................36 HELP ......................................................................................................................................37 Help Topics.......................................................................................................................37 About Neplan ....................................................................................................................37 VARIANT MANAGER ..............................................................................................................38 Variants ............................................................................................................................38 Diagrams ..........................................................................................................................38 All Elements ......................................................................................................................38 Elements............................................................................................................................39 TOOLBAR ...............................................................................................................................40 MOUSE BUTTONS ..................................................................................................................41 NEPLAN User's Guide V5
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Left Mouse Button.............................................................................................................41 Right Mouse Button ..........................................................................................................41 ELEMENT DATA INPUT AND MODELS ..........................................................................1 DATA INPUT DIALOGS OF NETWORK ELEMENTS .....................................................................1 Classification of Data in the Data Input Dialog ................................................................1 Element - Info .....................................................................................................................2 Element - Reliability ...........................................................................................................3 Element - User Data ...........................................................................................................3 Element - More…................................................................................................................4 STATION ..................................................................................................................................7 NODE .......................................................................................................................................9 DC NODE ..............................................................................................................................11 LINE.......................................................................................................................................12 ASYMMETRICAL LINE ............................................................................................................20 DC LINE ................................................................................................................................26 LINE-COUPLING .....................................................................................................................28 PYLON ...................................................................................................................................33 COUPLER ...............................................................................................................................34 REACTOR ...............................................................................................................................36 TRANSFORMER ......................................................................................................................38 ASYMMETRICAL TRANSFORMER............................................................................................51 THREE WINDINGS TRANSFORMER .........................................................................................55 FOUR WINDINGS TRANSFORMER ...........................................................................................62 SHUNT ...................................................................................................................................66 CONVERTER ...........................................................................................................................70 SVC (CONTROLLED STATIC VAR COMPENSATOR)...............................................................78 STATCOM (STATIC COMPENSATOR) ...................................................................................82 TCSC ....................................................................................................................................85 UPFC ....................................................................................................................................89 NETWORK FEEDER.................................................................................................................92 SYNCHRONOUS MACHINE ......................................................................................................95 ASYNCHRONOUS MACHINE .................................................................................................116 PS-BLOCK ...........................................................................................................................130 LOAD ...................................................................................................................................134 DC LOAD ............................................................................................................................144 LINE LOAD ..........................................................................................................................146 USER DEFINED SCALING FACTORS ......................................................................................151 FILTER .................................................................................................................................155 SERIE-R-L-C (WITHOUT EARTH CONNECTION) ...................................................................160 PARALLEL-RLC ..................................................................................................................163 SERIE-E-RLC (WITH EARTH CONNECTION) ........................................................................166 DISCONNECT-SWITCH ..........................................................................................................169 LOAD-SWITCH .....................................................................................................................171 CIRCUITBREAKER ................................................................................................................173 FUSE ....................................................................................................................................175 OVERCURRENT RELAY ........................................................................................................176 DISTANCE RELAY ................................................................................................................178 FREQUENCY RELAY .............................................................................................................179 VOLTAGE RELAY .................................................................................................................180 POWER RELAY .....................................................................................................................181 NEPLAN User's Guide V5
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CURRENT TRANSFORMER ....................................................................................................182 VOLTAGE TRANSFORMER ....................................................................................................183 HARMONIC CURRENT SOURCE.............................................................................................184 HARMONIC VOLTAGE SOURCE ............................................................................................185 SERIES EQUIVALENT LF ......................................................................................................186 SERIES EQUIVALENT SC ......................................................................................................188 SHUNT EQUIVALENT LF ......................................................................................................190 SHUNT EQUIVALENT SC ......................................................................................................192 EARTH SWITCH ....................................................................................................................194 SURGE ARRESTER ................................................................................................................195 MEASUREMENT DEVICE ......................................................................................................196 CONTROL CIRCUIT CCT ......................................................................................................198 FUNCTION BLOCKS ..............................................................................................................200 LOAD FLOW ...........................................................................................................................1 CALCULATION PARAMETERS (LF)...........................................................................................1 RESULTS (LF)..........................................................................................................................6 Select Results ......................................................................................................................6 Show Results .......................................................................................................................6 THEORY OF LOAD FLOW CALCULATION ................................................................................10 VOLTAGE DROP CALCULATION .............................................................................................16 REFERENCE VOLTAGES ..........................................................................................................18 DESCRIPTION OF THE RESULTS ..............................................................................................18 CONTINGENCY (OUTAGE) ANALYSIS ....................................................................................19 CALCULATION WITH DISTRIBUTED SLACK ............................................................................19 CALCULATION WITH LOAD BALANCE ....................................................................................19 AREA/ZONE CONTROL (LF)...................................................................................................20 Wheeling not allowed (option disabled)...........................................................................22 Wheeling allowed (option enabled)..................................................................................24 ASYMMETRICAL LOAD FLOW ................................................................................................26 LOAD FLOW WITH LOAD PROFILES ........................................................................................28 Calculation Parameters....................................................................................................28 Results...............................................................................................................................29 Theory...............................................................................................................................31 OPTIMAL POWER FLOW (OPF, TRANSMISSION) .......................................................1 CALCULATION PARAMETERS (OPF) ........................................................................................1 RESULTS (OPF) .......................................................................................................................7 Select Results ......................................................................................................................7 Show Results .......................................................................................................................7 DESCRIPTION OF THE PROGRAM ..........................................................................11 OBJECTIVE FUNCTION ...........................................................................................................12 RUNNING THE OPF PROGRAM ...............................................................................................13 SHORT CIRCUIT....................................................................................................................1 CALCULATION PARAMETERS (SC)...........................................................................................1 Parameter ...........................................................................................................................1 Faulted nodes .....................................................................................................................3 Faulted lines .......................................................................................................................5 Special fault ........................................................................................................................5 RESULTS (SC)..........................................................................................................................9 NEPLAN User's Guide V5
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Show Results .......................................................................................................................9 THEORY OF SHORT CIRCUIT CALCULATION...........................................................................15 A Comparison of the Methods:.........................................................................................17 Network Type IEC ............................................................................................................18 The Initial Short Circuit Current Ik" ................................................................................20 The Initial Short Circuit Power Sk"..................................................................................20 The Peak Short Circuit Current Ip ...................................................................................20 The Short Circuit Breaking Current Ib.............................................................................21 The Steady State Current Ik..............................................................................................22 The Thermal Short Circuit Current Ith.............................................................................23 The D.C. Component of Short Circuit Current iDC.........................................................23 The Asymmetrical Breaking Current Iasy ........................................................................23 The ANSI/IEEE-currents ..................................................................................................24 The symmetrical 0.5 cycles current ..................................................................................24 The asymmetrical 0.5 cycle current..................................................................................24 The symmetrical interrupting current (x cycles current)..................................................24 The symmetrical steady state (30 cycles) current.............................................................25 ANSI Standard C37.013 ...................................................................................................25 CALCULATION OF PARTIAL NETWORKS (SC) ........................................................................27 SELECTIVITY ANALYSIS....................................................................................................1 THE SELECTIVITY MODULE ......................................................................................................1 Installation..........................................................................................................................1 Functions of the independent E_SelModul.exe module......................................................1 Functions of the interactive graphic E_E32.exe ................................................................2 GENERAL .................................................................................................................................3 The menus and icons...........................................................................................................3 The list of elements .............................................................................................................3 System parameters ..............................................................................................................4 Project information.............................................................................................................4 INTEGRATION IN THE INTERACTIVE GRAPHIC ...........................................................................5 General ...............................................................................................................................5 Editing of protection device data........................................................................................5 Protection device response.................................................................................................7 Creating selectivity diagrams .............................................................................................7 Editing selectivity diagrams ...............................................................................................9 Parameters..........................................................................................................................9 THE CURRENT-TIME DIAGRAMS .............................................................................................10 General .............................................................................................................................10 Diagram properties ..........................................................................................................10 Saving the diagram or copying to the clipboard ..............................................................12 THE CHARACTERISTIC EDITOR ...............................................................................................13 The dialog window............................................................................................................13 Graphical input and editing of characteristics.................................................................14 Numerical input of characteristic points ..........................................................................15 Specifying standard characteristics..................................................................................15 Creating tolerance characteristics ...................................................................................16 THE MODULE EDITOR .............................................................................................................17 Editing of protection modules...........................................................................................17 Characteristics..................................................................................................................18 Coding of the setting ranges .............................................................................................22 NEPLAN User's Guide V5
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Tolerances ........................................................................................................................22 Setup of protection modules .............................................................................................23 THE DEVICE EDITOR ...............................................................................................................25 General .............................................................................................................................25 Adding new protection devices, wizards...........................................................................25 Editing of protection devices ............................................................................................26 THE DIAGRAM EDITOR ...........................................................................................................35 The selectivity diagram dialog window ............................................................................35 Editing selectivity diagrams .............................................................................................36 DOCUMENTATION, PRINT OUTPUT .........................................................................................38 General .............................................................................................................................38 Library data......................................................................................................................39 Protection device setting tables and selectivity diagrams................................................39 DISTANCE PROTECTION....................................................................................................1 OVERVIEW ...............................................................................................................................1 MENU OPTIONS FOR RELAYS ...................................................................................................2 STARTER ..................................................................................................................................4 Overcurrent ........................................................................................................................4 Under Impedance ...............................................................................................................4 Starter Characteristic L-L ..................................................................................................6 Earth Faults Detection .......................................................................................................8 Starter Characteristic L-E ..................................................................................................9 TRIPPING ...............................................................................................................................10 Impedance Stages for User Defined Relay .......................................................................10 Tripping Characteristic L-L .............................................................................................11 Tripping Characteristic L-E .............................................................................................11 Setting Parameters for Predefined Relays........................................................................11 ABB REL316.....................................................................................................................12 Siemens 7SA511, 7SA513 .................................................................................................13 AEG PD531, PD551, SD36..............................................................................................14 Back-up Protection ...........................................................................................................15 Automatic Impedance Setting ...........................................................................................16 TRIPPING TIME ......................................................................................................................19 Input..................................................................................................................................19 Automatic Time Setting.....................................................................................................19 VIEW .....................................................................................................................................20 Starter ...............................................................................................................................20 Tripping ............................................................................................................................20 Tripping Schedule.............................................................................................................21 Network Impedances (Impedance Path)...........................................................................22 Dimensions .......................................................................................................................22 PARAMETER (DP) ..................................................................................................................24 Global Parameter (DP) ....................................................................................................24 Relay-Specific Parameters ...............................................................................................26 TRIPPING SCHEDULES ............................................................................................................27 Build-up ............................................................................................................................27 Edit....................................................................................................................................27 Scrolling forward/backward.............................................................................................28 PROCEDURE FOR ENTERING A RELAY ....................................................................................29 RELAY DOCUMENTATION ......................................................................................................30 NEPLAN User's Guide V5
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CHECKING THE RELAY SETTINGS ..........................................................................................33 Fault Locations.................................................................................................................33 Line Faults........................................................................................................................33 Evaluation According to Fault Locations ........................................................................33 Evaluation According to Relay Location..........................................................................36 HARMONIC ANALYSIS........................................................................................................1 CALCULATION PARAMETERS (HA)..........................................................................................1 THEORY OF HARMONIC AND AUDIO FREQUENCY ANALYSIS ...................................................3 RESULTS (HA).......................................................................................................................11 Select Results ....................................................................................................................11 Results Table.....................................................................................................................11 Graphical Results .............................................................................................................13 MOTOR STARTING...............................................................................................................1 CALCULATION PARAMETERS (MS)..........................................................................................1 THEORY OF MOTOR STARTING CALCULATION ........................................................................2 Voltage Drop ......................................................................................................................4 RESULTS (MS).........................................................................................................................5 Select Results ......................................................................................................................5 Results tables ......................................................................................................................5 Graphical Results ...............................................................................................................5 NETWORK REDUCTION .....................................................................................................1 INTRODUCTION ........................................................................................................................1 SELECTION OF THE NETWORK TO BE REDUCED .......................................................................1 NETWORK REDUCTION FOR LOAD FLOW .................................................................................2 NETWORK REDUCTION FOR SHORT CIRCUIT............................................................................2 VOLTAGE STABILITY .........................................................................................................1 CALCULATION PARAMETERS ...................................................................................................1 Sensitivity Analysis / Modal Analysis .................................................................................1 U-Q Curves.........................................................................................................................2 P-U Curves .........................................................................................................................2 Result Files .........................................................................................................................3 RESULTS ..................................................................................................................................4 Graphical Results ...............................................................................................................4 Result Tables.......................................................................................................................5 THEORY ...................................................................................................................................6 Introduction ........................................................................................................................6 U-Q Sensitivity Analysis .....................................................................................................6 Q-U Modal Analysis ...........................................................................................................7 U-Q Curves.........................................................................................................................8 P-U Curves .........................................................................................................................9 SMALL SIGNAL STABILITY...............................................................................................1 CALCULATION PARAMETERS ...................................................................................................1 Calculation .........................................................................................................................1 Result Files .........................................................................................................................1 RESULTS ..................................................................................................................................2 Graphical Results ...............................................................................................................2 Result Tables.......................................................................................................................3 NEPLAN User's Guide V5
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THEORY ...................................................................................................................................4 TRANSIENT STABILITY ......................................................................................................1 GENERAL REMARKS ................................................................................................................1 Simulation method ..............................................................................................................1 TERMS AND DEFINITIONS, PER-UNIT SYSTEM .........................................................................4 Terms and Definitions ........................................................................................................4 Per-Unit System ..................................................................................................................4 NETWORK ELEMENTS ..............................................................................................................7 Controlled Admittance........................................................................................................7 Simulation...........................................................................................................................9 Maximum-minimum relays ...............................................................................................10 Distance protection...........................................................................................................11 Pole slip protection...........................................................................................................15 Overcurrent protection .....................................................................................................17 PROGRAM CONTROL ..............................................................................................................21 Simulation run and table output .......................................................................................21 Simulation parameters......................................................................................................22 SYMBOL LIBRARY ...............................................................................................................1 OVERVIEW ...............................................................................................................................1 BASIC CONCEPTS .....................................................................................................................1 Symbols of Network Elements.............................................................................................1 Symbols of Protection Devices and Switches .....................................................................2 Symbols for "General Elements" ........................................................................................2 Disconnection Symbol and Flow Indicator ........................................................................2 Drawing Symbols................................................................................................................3 MOUSE BUTTONS ....................................................................................................................3 Select Mode.........................................................................................................................3 Drawing Mode....................................................................................................................3 Double-Click.......................................................................................................................3 GRAPHICAL ELEMENTS ............................................................................................................4 Line Width (Symbol Library)..............................................................................................4 REFERENCES .........................................................................................................................1 ADDITIONAL REFERENCES .......................................................................................................1 APPENDIX............................................................................................................................527 THE STRUCTURE OF THE IMPORT-/EXPORT-FILES ...............................................................527 EDT-File.........................................................................................................................527 NDT-File.........................................................................................................................533 Measurement Data / Load Factor Files .........................................................................535 Harmonic limit file..........................................................................................................536
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NEPLAN User's Guide V5
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Tutorial
Tutorial Introduction NEPLAN is a very user friendly planning and information system for electrical-, gas- and water-networks. All menu options and calculation modules are described in details in the following chapters. To get to know NEPLAN in a quick and easy way, we recommend you to follow this tutorial. The program will be explained by examples and we show how to start a new project and how to build a small power system. That means, that the user will learn how to enter the elements graphically, how to enter data, how to use libraries, how to run calculations and how to present the results in a manner adapted to the objectives of the analysis. As mentioned, the Tutorial is a first step to get used to the NEPLAN software. For details about models of elements, data input or calculation inputs, please consult the respective chapters of the User's Guide or use the context sensitive Online Help.
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The User Interface 1
2
3
6
5 4
7
8
Fig. 1.1 Window features in the user interface
The numbers indicate the following window features: 1. Titlebar 5. Variant Manager 2. Menu option bar 6. Symbol Window 3. Toolbar 7. Message Window 4. Workspace with diagrams and data tables 8. Status bar
Toolbar All command buttons are equipped with balloon help texts, which pop up when the cursor is held still at the button for a moment without pressing any keys. Many commands, which can be accessed in the Toolbar, may be found as well in the respective menus. Others, mainly the graphical commands can only be accessed in the Toolbar.
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Workspace In the Workspace the different diagrams can be opened. The same diagrams may be used for entering the network, building control circuits or sketching drawings.
Variant Manager The Variant Manager gives a good overview of the open projects and variants. New projects and variants may be managed, what means that they can be deleted, added, activated or deactivated. From the Variant Manager, the user can switch to the Diagram Manager, which administrates the open Diagrams with its graphic layers.
Symbol Window The Symbol Window contains all element symbols available. Apart from the standard symbol for some elements there exist other symbols with a different graphical appearance but exactly the same characteristics. New symbols also can be created or existing symbols may be modified with the Symbol Library.
Message Window The message window is the channel to communicate with the user. It supplies information about the executed processes, error messages and further information.
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The Online Help 2
1
Fig. 1.2 How to call the Online Help
The figure above shows how to call the Online Help. With button 1) a context sensitive help is called, what means, that after pressing this button, the user may click on the feature or dialog for which he needs more information. Selecting the Help Topics in the menu Help or pressing F1, the user can get more information with a topic or with an index search.
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Data Organization
Fig. 1.3 Data Organization of NEPLAN
The figure above shows the data organization of NEPLAN. The NEPLAN directory contains the following folders: Bin:
contains executable and control files
Dat:
contains Examples and NEPLAN projects
Hardlock:
contains the executable file for the Hardlock driver
HTML Help:
contains the HTML Help files
Lib:
contains NEPLAN Libraries
Manuals:
contains the manuals as pdf files
Ramses:
contains files of the module Ramses
temp:
contains temporary files
user:
contains User files and projects
During the installation process, an entry in the operational system registry will be made by NEPLAN. It's the information about where the program can find the different folders to save and read data.
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The Basic Elements of NEPLAN To understand the NEPLAN environment, it is essential that certain concepts used in the system are described:
Station
Node
Node
Node
Network Feeder
Disconnect, Load Switch Load Logical Switches
Fig. 1.4 One line diagram with network components
An electrical power system consists of nodes and elements.
Nodes A node is the connection point of two elements or a location, where electrical energy will be produced or consumed (generator, load). A node is described by its • Name, • nominal system voltage in kV, • zone and area, • type of node (main bus bar, bus bar, sleeve, special node), • description, The nominal system voltage Un is the line-to-line voltage, for which a power system is designated and on which several characteristics of the power system has been referred. In NEPLAN the nominal system voltage of the nodes must be entered during the node data input. Every voltage is given as a line-to-line voltage (delta voltage). It is not necessary to past a node in between all elements. They may also be connected directly with a link. In this case no node results will be presented and not more than two elements can be connected together in the same point.
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Elements An element corresponds to a network component, like e.g. line, transformer or electrical machine. There are active elements and passive elements. An element is described topological by a starting and an ending node. For three windings transformers a third node must be given. The elements will be described electrical by • the rated current, rated power and rated voltage and • its parameters, such as losses, reactances, ... In NEPLAN these parameters are entered with input dialogs. The active elements are network feeders, asynchronous machines, synchronous machines and power station units. A network feeder represents a neighboring network. The passive elements are lines, couplings, switches, reactors, two and three windings transformers, shunts and loads. The loads can also be entered along a line without entering nodes (line loads). Modeling of Active Elements For a short circuit calculation the active elements are modeled with the help of their subtransient reactance. For a load flow calculation these elements will be represented by resistive and reactive powers (PQ-nodes) or by voltage magnitude and angle (slack nodes) at the node. The network feeder usually will be modeled as a slack node.
Protection Devices, Current and Voltage Transformers Protection devices (overcurrent relays, distance protection relays, circuit breakers) and current or voltage transformers are associated with the built-in node and the switching element. They have no influence on the load flow and short circuit calculation. Only their limits are checked during the calculation. These elements are used in the relay coordination modules.
Station A station can contain several nodes and has no meaning for the calculations or for protection device coordination. It will only be used in relation to the database.
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Symbol For each element type there are different symbols in the Symbol Window. Choose the one you want to past in the diagram. A Symbol Library is included in the NEPLAN package, where user defined symbols may be created.
Switches In NEPLAN the switches are used to change the network topology (switching on/off elements). There are two different types of switches: • physical switch and • logical switch. Physical switches are couplings, circuit breakers and disconnect or load switches. Logical switches are fictive switches, which are assigned to all elements by the system. A line, for example, has two logical switches, one at the starting and one at the ending node. A physical switch has no logical switch, because it will already be switchable. During the input of a network, the physical switches can be neglected, because switching can be done with the help of the logical switches. This has a disadvantage, when a line leads to a double bus bar system. Switching from one bus bar to an other, the user has to change the starting or the ending node of the line. If the user enters two disconnect switches (one to each bus bar) with an additional node in between, the switching can be done with the disconnect switches. The physical switches can be reduced during the calculation (see the Parameters dialog of the respective calculation modules).
Zones and Areas Zones and areas are network groups, which may be defined. This means, that every element and node belongs to a zone and to an area. An area normally includes one or more zones. For load flow calculation it's possible to define transactions between zones and between areas. Each zone and area may be presented in a different color. In Step 4 - E it will be explained how to define zones and areas.
Partial Networks Unlike zones and areas, a partial network is an independent network. A partial network has no connections to any other networks. You can make partial networks by opening logical or physical switches. It is possible to color each partial network differently (see below).
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Station
Partial network 1
Node
Node
Node
Network feeder
Disconnect, Line
Load switch
logical switch "open"
Partial network 2
Fig. 1.2 Partial networks
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Step 1 – Create a new project To create a new project, after having started the program, click on the menu "File – New". 1. Enter the location or directory for saving the project. Pressing the button "…", you can choose the directory. 2. Enter the project name. 3. Choose the network type: Electric, Water or Gas. 4. If you wish, you may enter a project description. 5. Choose the diagram size and the page orientation. 6. Press the OK button.
1 2
3
4
5 6
Fig. 1.5 Create a new project
The figure below shows the user interface after having created the new project. a. The titlebar shows the name of the active project. b. One diagram is open for the rootnet. c. The variant manager shows the project tree, which consists at the moment of only one rootnet.
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a
b c
Fig. 1.6 After creating a new project
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Step 2 – Enter a small network In this step, you'll enter nodes and elements to build a small electrical network. The Symbol window allows you to choose the desired element symbol in an easy way. You can start entering any element you want. It is not necessary to enter first the nodes, because the new philosophy of NEPLAN is to first enter the elements and nodes independently in the diagram, and then to connect them with a link. Only lines can't be entered independently. They need connection points, which are nodes or other elements. It's not necessary to enter a node between all elements, because the elements can be interconnected directly with a link. However, if the user wants to see the node results, he has to enter the node graphically.
Input data We will draw the following network:
Fig. 1.7 Network to be entered in NEPLAN
The necessary parameters are all listed in the following tables. 1-12
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Network Feeder: Name Sk''max Ik''max R(1)/X(1) Z(0)/Z(1) C1
Sk''min Ik''min R(1)/X(1) Z(0)/Z(1) LF- U oper Uw oper Poper Qoper
-
MVA
kA
max
max
uF
MVA
kA
min
min
Type
%
Deg
MW
Mvar
NETZ
1500
3.936
0.1
1.667
0
1500
3.936
0
0
SL
100
0
0
0
Lines: Name Length Numb
Units
R(1)
km
X(1)
C(1)
G(1)
Ohm/.. Ohm/.. uF/...
R(0)
X(0)
C(0)
Ir min Ir max Red. fact. Q mm2
uS/... Ohm/.. Ohm/.. uF/...
A
A
mm2
LEIT. 1
1.16
1
Ohm/km 0.103
0.403
0.009
0
0.150
1.400
0.005
0
90
1
0
LIN 2- 4
1.16
1
Ohm/km 0.103
0.403
0.009
0
0.140
1.499
0.005
0
90
1
0
LIN 2- 3
0.59
1
Ohm/km 0.103
0.403
0.009
0
0.140
1.599
0.005
0
70
1
0
LIN 4- 8
0.20
1
Ohm/km 0.113
0.410
0.009
0
0.150
1.599
0.004
0
100
1
0
LIN 3- 8
0.37
1
Ohm/km 0.113
0.413
0.009
0
0.153
1.619
0.004
0
75
1
0
LIN 3- 9
0.16
1
Ohm/km 0.113
0.413
0.009
0
0.154
1.639
0.004
0
60
1
0
LIN 7- 6
1.61
1
Ohm/km 0.066
0.382
0.010
0
0.085
1.459
0.004
0
400
1
0
LIN 5- 2
7.80
1
Ohm/km 0.091
0.415
0.009
0
0.130
1.659
0.004
0
200
1
0
LIN 5- 6 11.90
1
Ohm/km 0.141
0.413
0.009
0
0.160
1.649
0.004
0
190
1
0
LIN 8- 7 19.10
1
Ohm/km 0.112
0.400
0.009
0
0.144
1.587
0.005
0
200
1
0
Loads: Name
LF Type
P
Q
Domestic Units
Units
V_ZWOELF
PQ
5
4
0
HV
V1
PQ
2
2
0
HV
Synchronous Machines: Name
Sr
Ur
pUr
cosphi
xd sat
xd' sat
xd'' sat
x(2)
x(0)
Ufmax/ur
Ikk
-
MVA
kV
%
-
%
%
%
%
%
-
kA
GEN 1
45
8.5
0
0.85
160
0
20
20
20
2
0
Name
mue
RG
Turbo
Amort. Winding
Unit Geneator
Motor
LF-Type
P oper
Q oper
-
-
Ohm
-
-
-
-
-
MW
Mvar
GEN 1
0
0
1
1
1
0
PQ
40
10
Transformers: Name
From
To
Node
Node
Vector Unit
Comp.
Sr
Ur1
Ur2
ukr(1)
uRr(1)
ukr(0)
uRr(0)
kV
kV
%
%
%
%
Group Transf. Winding MVA
TRA8 -12
EIGHT
TRA6 -13
SIX
YD,05
0
0
60
65
16
10
0
10
0
THIRTEEN YD,05
0
0
140
65
8.5
10
0
10
0
TRA8 -11
EIGHT
ELEVEN
TRA9 -10
NINE
TEN
YD,05
0
0
12
65
5.2
10
0
10
0
YD,05
0
0
6
65
5.2
8.46
0
8.46
0
TRA1-2
ONE
TWO
YY,00
0
0
200
220
65
9
0
9
0
Name
I0
Pfe
U01(0)
U02(0)
Earthing
RE1
XE1 ZE1 active
%
kW
%
%
primary
Ohm
Ohm
TWELVE
NEPLAN User's Guide V5
%
Earthing
RE2
XE2
ZE2 active
secondary
Ohm
Ohm
%
1-13
Tutorial
TRA8 -12
0
0
0
0
impedance
0.1
0
100
impedance
6
0
100
TRA6 -13
0
0
0
0
direct
0
0
100
direct
0
0
100
TRA8 -11
0
0
0
0
direct
0
0
100
direct
0
0
100
TRA9 -10
0
0
0
0
direct
0
0
100
direct
0
0
100
TRA1-2
0
0
0
0
direct
0
0
100
impedance
1
35
100
Name
On-load
Tap side Controlled Tap act Tap min Tapr Tap max Delta U Beta U Uset Pset Sr min Sr max
Tapchanger
bus
%
°
%
%
MVA
MVA
TRA8 -12
0
Primary
Primary
0
0
0
0
0
0
0
0
60
60
TRA6 -13
0
Primary
Secondary
0
0
0
0
0
0
0
0
140
140
TRA8 -11
0
Secondary
Primary
0
0
0
0
0
0
0
0
12
12
TRA9 -10
0
Secondary
Primary
0
0
0
0
0
0
0
0
6
6
TRA1-2
1
Primary
Secondary
0
-10
0
10
2
0
100
0
200
200
Asynchronous Machines: Name
From
Pr
Sr
Ur
Ir
cosphi
eta
Conv.- cosphi Ma/Mr Mk/Mr Rm
sr
Node
MW
MVA
kV
A
-
-
-
-
pairs
Drive
start
-
-
Ohm
%
Ia/Ir Number Pole-
U3 5.2 ELEVEN
5
6.6489 5.2 0.738
0.8
0.94
5
1
1
1
0.3
0.9
2.2
0
2
U1 5.2
TEN
5
6.6489 5.2 0.738
0.8
0.94
5
1
1
1
0.3
0.9
2.2
0
1.8
Name
J
H
LF type
P oper
Q oper
ANSI
Load
M0
M1
M2
M0,1,2
Model
kg*m2
s
-
MW
Mvar
factor
torque
U3 5.2
100
0.742
PQ oper
2
1
1.5
Parabola
4500
0
7000
1
3. Order
U1 5.2
100
0.742
PQ oper
4
3
1.5
Parabola
3500
0
7000
1
3. Order
Node
Un
Frequ.
Umin
Umax
Ir
Ipmax
Type
kV
Hz
%
%
A
kA
in Nm
Nodes: Name
THREE
Busbar
65
50
0
0
0
0
FOUR
Busbar
65
50
0
0
0
0
TEN
Busbar
5.2
50
0
0
0
0
TWELVE
Busbar
16
50
0
0
0
0
SEVEN
Busbar
65
50
0
0
0
0
ELEVEN
Busbar
5.2
50
0
0
0
0
THIRTEEN
Busbar
8.5
50
0
0
0
0
ONE
Busbar
220
50
0
0
0
0
TWO
Busbar
65
50
0
0
0
0
EIGHT
Busbar
65
50
0
0
0
0
SIX
Busbar
65
50
0
0
0
0
FIVE
Busbar
65
50
0
0
0
0
NINE
Busbar
65
50
0
0
0
0
Enter the network
1-14
NEPLAN User's Guide V5
Tutorial
Enter an element 1. To draw an element from the symbol window, click on it, hold the mouse button pressed, drag the symbol to the diagram and drop it. 2. A data-input-dialog for the element appears. 3. Enter a name for the element. 4. Enter the element parameters. 5. Press the OK-button when finished.
2 1
3 1
4
5
Fig. 1.8 Enter an element
Enter a node 6. To enter nodes, click on one of the node button in the Toolbar. 7. Click once in the diagram for a round-point-node. To draw a bar-node, click in the diagram, but hold the mouse button and move the mouse to define the length of the bar-node, then leave the mouse button. 8. A data-input-dialog for the node appears. 9. For the node data at least the nominal system voltage and frequency are required. 10.Press the OK-button when finished.
NEPLAN User's Guide V5
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Tutorial
6 8
7 9
10
Fig. 1.9 Enter a node Enter a link 11.To interconnect elements with elements or with nodes, use the links. Press on the link-button. 12.First click on one end of the element. 13.Then click on the node to finalize the link.
1-16
NEPLAN User's Guide V5
Tutorial
11
12
13
Fig. 1.10 Interconnecting the elements with Links
Build up the whole network (Hint for entering lines) 14.Build up the network in the same manner as explained before. To enter lines you need nodes where to connect them. 15.For entering lines press on the Line-button. 16.Click on the starting-node. 17.Click in the diagram, wherever you wish to have supporting points. 18.Click on the ending-node 19.Enter the line data in the appearing dialog. 20.Press OK when finished.
NEPLAN User's Guide V5
1-17
Tutorial
15
19
16
17
20 18
Fig. 1.11 Enter a line
Enter a text field 21.Click on the text-button. 22.Click in the diagram. The text field will be inserted and you may enter a text.
1-18
NEPLAN User's Guide V5
Tutorial
21 22
Fig. 1.12 Enter a text field
23.To change the properties of the text field, select it and press the right mouse button. 24.In the appearing pop-up menu choose Graphic Properties and the dialog appears. 25.You may change the text and the font or apply a frame and colors.
NEPLAN User's Guide V5
1-19
Tutorial
23
25 24
Fig. 1.13 Change the text field properties
Test your network After having entered the network with all nodes and elements data, you should check if all elements are linked and all data is entered correctly. For this reason perform a load flow calculation with "Analysis – Load Flow - Calculation". Watch out for any error messages in the Message Window and correct your network, till the load flow calculation is running successfully. In case that you get an error message for a certain element, the elements ID will be indicated. There is a feature in NEPLAN to search this element in an easy way: Search for an element 1. Choose the Search-feature in the Edit-menu. 2. Select the search-criteria. In this case choose “Id”. 3. Enter the ID of the element you are looking for. 4. Press the button Find Next.
1-20
NEPLAN User's Guide V5
Tutorial
1
4
3 2
Fig. 1.14 Search for an element
5. The program will move the view of the network, so that the searched element is displayed in the center with an orange frame around it. 6. Use the button Show Dialog to show the data input dialog of the marked element. 7. Enter an other ID to look for an other element. 8. Press Cancel to finish the Search.
7 6 8 5
NEPLAN User's Guide V5
1-21
Tutorial
Fig. 1.15 Find the element
1-22
NEPLAN User's Guide V5
Tutorial
Step 3 – Insert Header, Save, Print, Exit
Insert Header In every diagram a header may be inserted and its data can be edited. 1. Insert a header with "Insert - Header". 2. Click in the diagram to past the header.
1
2
Fig. 1.16 Insert a header into the diagram
3. With "Options – Header" a dialog with the header text lines appears. 4. The text lines may be modified.
NEPLAN User's Guide V5
1-23
Tutorial
3
4
Fig. 1.17 Modify the header lines
5. With "Options – Project Description" a respective dialog appears. 6. You may modify the project description.
5
6
1-24
NEPLAN User's Guide V5
Tutorial
Fig. 1.18 Modify the project description
The project name and the variant name are displayed automatically in the header.
Save the network From time to time the network has to be saved to avoid data loss. Generally just do it by pressing the Save-Icon or with "File - Save". In the following it's shown how you save a network for the first time or how to save it with a different name. 1. Choose "File – Save as".
1
Fig. 1.19 Save a project
2. Choose the directory, where the project should be saved. 3. Enter the file-name. 4. Click on the button "Save"
NEPLAN User's Guide V5
1-25
Tutorial
2
3
4
Fig. 1.20 Enter the file-name
Print the diagram Use Page Setup, Print Setup and Print Preview to adjust all settings before you Print. To print the diagram on one page activate the option "Print on One Page". If this function is not activated, the diagram may be printed on several pages. 1. Use "Page Setup" for settings of the paper size and margins. 2. Use "Print Setup" for printer settings. 3. Make a print preview from the diagram. You may print from the preview window. 4. Print the diagram.
4
2
3 1
Fig. 1.21 Print the diagram
1-26
NEPLAN User's Guide V5
Tutorial
Close and open projects Projects may be opened and closed without quitting the program. Several projects can be open at the same time, they will be displayed in the variant manager. 1. Make a right-mouse-button click on the project symbol in the variant manager. A popup menu appears. 2. Choose "Close Project" to close the respective project. The same is possible with "File - Close".
1
2
Fig. 1.22 Close a project
3. Open an other, already existing project with "File – Open"
3
NEPLAN User's Guide V5
1-27
Tutorial
Fig. 1.23 Open a project
4. To exit the program use "File – Exit"
4
Fig. 1.24 Exit the program
1-28
NEPLAN User's Guide V5
Tutorial
Step 4 – Use of Diagrams, Layers, Areas and Zones In this step you will learn how to handle diagrams and graphic layers and you'll define areas and zones. We use the example network MyProject.nepprj, entered in Step 2.
Use of Diagrams For a certain project, the network may be entered in different diagrams. With the help of this function, the user can for instance enter the high voltage network in one diagram and the low voltage network in several other diagrams. The high voltage network could also be divided into several diagrams. An other use is zooming into stations. In the general diagram the station can be drawn as a "black box" and in an other diagram the station can be drawn in detail with all protection and switching devices. In this step, we will learn the handling of diagrams in a project.
Rename a Diagram The following figure explains the procedure to rename the single diagram in our project, which actually has the name Diagram 0. 1. Select the diagram manager. 2. Double click on the existing "Diagram 0" and the Diagram Properties dialog appears. 3. The name can now be changed to "MV-Network". 4. If you wish, insert a diagram description.
NEPLAN User's Guide V5
1-29
Tutorial
2
3 4
1
Fig. 1.25 Change of diagram name
Define a new diagram A low voltage network for the substation STAT-LV shall be inserted in an other diagram. We'll define this new diagram, like shown in the figure below: 1. Make a right-mouse-button click on the Diagram Manager and choose "Insert new Diagram". The Diagram Properties dialog appears. 2. Enter the name of the new diagram. 3. If you wish, insert a diagram description.
1-30
NEPLAN User's Guide V5
Tutorial
1
2 3
Fig. 1.26 Insert a new diagram
After having closed the Diagram Properties by clicking the OK-button, the following diagram structure is displayed.
Fig. 1.27 Rootnet with two diagrams
NEPLAN User's Guide V5
1-31
Tutorial
To display a diagram, check its checkbox and uncheck it for closing. The last checked diagram is the active one and can be edited.
Enter a low voltage network Activate the diagram "LV-network" and draw the following network.
Fig. 1.28 LV-Network, drawn in the new diagram
The necessary parameters are all listed in the following tables. Lines: Name
Type
Length Number
Units
R(1)
X(1)
C(1) G(1)
R(0)
X(0)
C(0) Ir min Ir max Red.
Ohm/.. Ohm/.. . . uF/... uS/... Ohm/... Ohm/... uF/...
km N-L2 KS 3x150/150
0.03
1
Ohm/km 0.1240 0.072
0
0
0.508
0.115
N-L1 KS 3x240/240
0.02
1
Ohm/km 0.0754 0.072
0
0
0.308
0.119
Q
A
A
fact. mm2
0
0
360
1
150
0
0
470
1
240
Loads: Domestic Units Units
Name
From node
LF Type
P
Q
N-V3
N3
PQ
20
10
0
LV
N-V2
N2
PQ
40
30
0
LV
1-32
NEPLAN User's Guide V5
Tutorial
Transformers: Name
Type
TRAFO-NS
16/0.4 KV 630 KVA
Name
TRAFO-NS
Name
From
To
Node
Node
TWELVE
NS_SS_N1
Comp.
Unit
Sr
Group Transf. Winding MVA DY,07
0
0
0.63
Ur1 Ur2 ukr(1) uRr(1) ukr(0) uRr(0) kV
kV
%
%
%
%
16
0.4
5.24
1.12
5.24
1.12
I0
Pfe
U01(0)
U02(0)
Earthing
RE1
XE1
ZE1 active
Earthing
RE2
XE2
ZE1 active
%
kW
%
%
primary
Ohm
Ohm
%
secondary
Ohm
Ohm
%
0
0
0
0
direct
0
0
100
direct
0
0
100
Tap Tap
Tapr
On-load
Tap side
Controlled
Tapchanger TRAFO-NS
Vector
0
Primary
bus
act
min
Secondary
0
0
Tap
Delta U Beta U Uset Pset Sr min Sr max
max
%
°
%
%
MVA
MVA
0
0
0
0
0
0.63
0.63
0
Nodes: Name
Node
Un
Frequ.
Ir
Ipmax
Type
kV
Hz
Umin Umax %
%
A
kA
N3
Sleeve
0.4
50
0
0
0
0
N2
Sleeve
0.4
50
0
0
0
0
NS_SS_N1
Busbar
0.4
50
0
0
0
0
Enter an element more than once in a project Elements may be represented graphically as many times as you want in the same project. Mainly this makes sense, when you wish to see the same element in different diagrams, like in our case. The substation STAT-LV, where the low voltage network is connected, shall be represented in the LV- and in the HVdiagram to connect the two networks. It concerns the substation symbol and the node TWELVE. To draw the node TWELVE a second time follow the instructions: 1. Select the node symbol as usual and draw the node in the diagram. 2. In the appearing Input-dialog, select the Info-tab. 3. Press the button beside the name field. 4. Select an already existing node from a list. 5. By pressing the OK-button, the data of the respective element will be adopted.
NEPLAN User's Guide V5
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Tutorial
1
2 3 1
4
5
Fig. 1.29 Enter an already existing element again in the same project.
After you entered the whole low voltage network, perform a Load Flow calculation to proof the entered data and the connections of the elements.
Use of graphic layers To each diagram, any number of graphic layers may be assigned. The user can decide, which graphic layers of a diagram shall be displayed simultaneously. The figure below shows the principle of diagrams and graphic layers.
1-34
NEPLAN User's Guide V5
Tutorial
Diagram 1
1 2 3
Graphic Layer 1-3 of Diagram 1
Diagram 2
1 2 Graphic Layer 1-2 of Diagram 2
Fig. 1.30 Assignment of graphic layers to diagrams
In each graphic layer any number of graphic elements, electric elements or nodes can be entered or bitmaps imported. Before you insert a new component, you can choose the graphic layer, to which it should belong. The graphic layers can be displayed selectively. For example, it's possible to use different layers for current transformers and relays. If you are doing load flow calculation, you could switch off the layer for the relays. If you are doing relay coordination you can switch on the relay layer. In our example we'll introduce a second graphic layer for the HV-diagram with the name Areas/Zones. In the new graphic layer, we will draw the regions of network areas and zones. We then have the possibility to display or not this graphical input, by switching on or off the respective graphic layer.
Insert new graphic layers Follow the instructions to insert new graphic layers: 1. In the Diagram Manager make a right-mouse-button click on the diagram symbol "HV-Network". 2. In the menu choose "Insert new Graphic Layer".
NEPLAN User's Guide V5
1-35
Tutorial
1
2
Fig. 1.31 Add a new graphic layer to the diagram "HV-Network"
3. In the "Graphic Layer Parameters" – dialog, enter the name of the graphic layer. 4. If you wish, you may write a description.
3
4
Fig. 1.32 Enter the graphic layer parameters
Finally the Diagram Manager will look like this:
1-36
NEPLAN User's Guide V5
Tutorial
Fig. 1.33 Diagram Manager after entering the new graphic layer
Enter drawings in the new graphic layer To be able to edit a graphic layer, it has to be activated. 1. Activate the new graphic layer Areas/Zones of the diagram HV-Network, either by mouse click in the checkbox or by choosing the right option in the menu, which appears with a right-button mouse click. 2. Draw the regions for an area and a zone and write a text, like in the figure below, by using the graphical tools in the toolbar.
2
1
2
NEPLAN User's Guide V5
1-37
Tutorial
Fig. 1.34 Input for the graphic layer "Areas/Zones" of the diagram "HV-Network"
Actually, both graphic layers (GrLayer 0 and Areas/Zones) are shown. Switch off the graphic layer "Areas/Zones", so that only the network is displayed. 1. To be able to switch off the graphic layer Areas/Zones, it mustn't be active. For that reason, activate the other graphic layer. 2. Right-mouse-button click on the symbol of the "Areas/Zones" layer. 3. Unselect the "Show Graphic Layer" option.
1 2
3
Fig. 1.35 Switch off the graphic layer "Areas/Zones"
Now, the graphical elements we entered before disappeared and only the network is visible. A red cross over the graphic layer symbol indicates, that the "Areas/Zones" layer is not shown, respectively switched off:
1-38
NEPLAN User's Guide V5
Tutorial
Fig. 1.36 Only the graphic layer "GrLayer 0" is shown
Define and assign Areas and Zones Areas and zones are both network groups and can be defined by the user. Every element and node belongs to one zone and to one area. An area normally includes one or more zones. For load flow calculation it is possible to define transactions between different zones and between different areas. When creating a new project, there is one area and one zone predefined and every entered element is assigned to these network groups. After an element has been entered its area and zone may be changed. There are different possibilities to assign an area or/and a zone to network elements. They will be explained below. In general areas and zones have to be defined first, before they can be assigned to elements.
Define areas and zones To define areas and zones, choose "Edit – Variant Properties". 1. Select the "Areas" tab first. 2. In the list, there exists only the predefined area. To add a new area click on the respective button. 3. Enter the name of the area 4. Choose a color. 5. Press the OK button.
NEPLAN User's Guide V5
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Tutorial
1
3
2
4
5
Fig. 1.37 Define a new area “Area_red”
Let us change the color of Area 1. 1. Select Area 1 in the Area tab. 2. Click on the Properties button. 3. Change the color. 4. Press the OK button.
1-40
NEPLAN User's Guide V5
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1 2
3
4
Fig. 1.38 Change the properties of Area 1
In the same manner define the zone Zone_motors: 1. Select the "Zones" tab first. 2. To add a new zone click on the respective button. 3. Enter the name of the zone and the color. 4. Different scaling factors for a zone may be defined. 5. Press the OK button.
NEPLAN User's Guide V5
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Tutorial
1
2 3
4
5
Fig. 1.39 Define zones
Now, zones and areas are defined and they can be assigned to the elements. You have several possibilities to do it.
Assign areas and zones to the elements, one by one As shown below, for every single element you may choose independently a zone and an area, which have been defined previously.
1-42
NEPLAN User's Guide V5
Tutorial
Fig. 1.40 Assign an area and a zone to an element
Assign areas and zones to a group of elements An other, much easier method is to mark a group of elements and to assign to all of them an area or/and a zone. 1. Mark a group of elements by using the mouse to put up a selection window or/and by clicking on different elements, while keeping the Shift-key pressed. 2. Choose "Assign Areas/Zones" and the "Assign Properties" – dialog will appear. 3. In the "Assign Properties" – dialog check the Area-box to assign an area to the elements. If you want to assign as well (or only) a zone to the elements, just mark the respective checkbox. 4. You now can select the name of the area, to which the element should belong to.
NEPLAN User's Guide V5
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Tutorial
5. As we marked a group of elements for the assignment, we choose the option "Assign to graphical selection". 6. Press the OK button.
1
2 1
4
3
5
6
Fig. 1.41 Assign an area (or/and a zone) to a group of elements
As a control, you can now open the Info tab of a Data Input Dialog of an element that belongs to this area and you'll notice that the area name has been changed.
Assign areas and zones to all elements of a partial network For this procedure you first have to create a partial network. This means, a part of the network has to be disconnected from the rest. 1. Disconnect the part of the network, which you want to assign to an area or/and zone. A partial network is built. 2. Get to the Assign Properties dialog by the menu option "Edit - Data – Assign Areas/Zones". 3. Select Area (or/and Zone) and choose the respective name.
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NEPLAN User's Guide V5
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4. Check the box "Assign to all elements of selected partial network" and select the ID of the partial network. If you don't know this ID, open the Data Input dialog of one element of this partial network and get it of the Info tab. 5. By pressing the OK button, the assignment will be finalized. Don't forget to reconnect the partial network.
2
1
3
4 5 6
Fig. 1.42 Assign an area (or/and a zone) to a partial network
You now have the possibility to color the network according to the different areas or zones. 1. Get to the Colors tab of the Diagram Properties with "Edit – Diagram Properties". 2. Select "Network Areas" for a coloration of the network according to areas. 3. Press the OK button and the coloration of the network will change.
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Fig. 1.43 Network coloration according to areas
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Step 5 – Create and use Libraries The NEPLAN Library File *.neplib may contain many element libraries, which are sorted by element type. In the following we explain how to create new libraries, how to copy library data to an element and how to export data from an element to a library.
Create a new Library The following steps explain how to create a new element library: 1. Choose "Libraries" in the menu "Libraries". The NEPLAN Library Application appears.
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Fig. 1.44 Open the Library Application
2. Select "File - New" to create a new Library File. 3. Enter the Library File name.
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Fig. 1.45 Create a new Library File
4. Select "Library – New Library" to create a new library. 5. Choose the element type, for which a library has to be created.
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Fig. 1.46 Create a new library
6. A new library appeared in the library tree. The libraries are sorted by element type. 7. Change the name of the new library
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Fig. 1.47 Change name of library
8. Insert a new Library Element (type) by selecting "Library Element - New".
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Fig. 1.48 Insert new library element
9. A new library element appeared in the library "50MVA".
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Fig. 1.49 New library element in the library "50MVA"
10.Change the type name of the library element. 11.Enter the data for the new library element. 12.If you wish, enter additional library elements. 13.If you wish, enter other libraries. 14.When finished, close the Library Editor with "File-Close".
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Fig. 1.50 Enter library data
Import data from a library When a network element has been entered in the diagram and you wish to copy the data from an element type of the library, proceed as follows: 1. In the Params tab of the Element-Data-Input-Dialog, press the button "…".
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Fig. 1.51 Copy the data from an element type of the library
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2. Choose the NEPLAN-Library-File, where the respective element type can be found. 3. Select the element type in the respective library. 4. To copy the data from the library to your element, click on the OK-button.
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Fig. 1.52 Choose the element type
Update your network data with a library type In case that the data of a certain element type in the library has been changed, you have the possibility to update this data easily in all network elements, which are of the same type. 1. Click on the Library button in the Data-Input-Dialog of an element with the respective element type. 2. In the Library dialog, select the element type. 3. Press the button "Update Data with Modal Type" to update the data in every network element with the same type. 4. Proceed in the same way to update other elements with a modified type. When finished, click the OK-button to close the dialog.
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Fig. 1.53 Update all elements of a certain element by the library data
Export data to a library In case that you entered data in the Data-Input-Dialog of an element and you want to create an element type of this data in a library, proceed as follows. 1. Enter a element type name in the element dialog. 2. Click on the Export-button in the Data-Input-Dialog of the element, to call the Library dialog. 3. Choose the Library File, whereto export the data. 4. If you want to create a new library, press this button (A new element type can be inserted in a new or in an already existing library). 5. Select the library, whereto the new element type should be added. 6. To finalize, click the OK-button.
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Fig. 1.54 Export data of an element to the library
7. When you open the Library dialog again, you'll recognize the new library element.
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Fig. 1.55 New element type
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In the same manner you may also update an already existing element type in a library. Select the library in which this element type already exists and press OK. You then will be asked if the existing element type shall be overwritten.
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Step 6 – Define variants
For calculating different cases, NEPLAN has the possibility to create different variants of the rootnet and to combine them with topology and loading data files. The following figure shows the principle.
BASE CASE or ROOT NETWORK
Variants
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Fig. 1.3 Variant Management System with NEPLAN
The variants are saved together with the Rootnet in the project file (.nepprj), for topology and loading data separate files will be defined. When activating a variant, assigned topology and loading files will be opened automatically. In this step 4, you'll get in contact with the concept of variants. In the following, different variants will be defined.
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Insert new Subvariants Variants first have to be created in the variant tree, before the modifications for the different variants can be saved. Several variants will be defined. 1. Make a right-mouse-button click on the rootnet symbol in the Variant Manager 2. Choose "Insert new Subvariant"
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Fig. 1.56 Insert new Subvariant
3. A "Variant Properties" dialog appears. 4. Enter a Name for the new variant and if you wish, a description.
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Fig. 1.57 Enter name and description
5. “Variant replacement” is displayed in the variant tree.
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Fig. 1.58 "Variant replacement" appears in the variant tree
6. Define an other variant “Variant additional” in the same way as before.
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Fig. 1.59 Define a variant "Variant additional"
7. Define two subvariants (Variant a and Variant b) of "Variant replacement"
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Fig. 1.60 Define subvariants "Variant a" and "Variant b"
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Save modifications to the variants A variant tree now has been created, but all variants still contain the same data. Now we will modify the different variants. 1. Activate “Variant replacement” by clicking on the checkbox. 2. As a modification for this variant, change the length and Ir of LIN 7-6.
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Fig. 1.61 Realize the modifications in "Variant replacement"
3. Deactivate “Variant replacement” by clicking on the checkbox. This is necessary if you wish to edit next a variant of the same tree branch. 4. You'll be asked, if you want to save the modifications in “Variant replacement”. Click on YES.
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Fig. 1.62 Save the modifications of “Variant replacement”
5. Activate Variant a 6. Notice that the modifications carried out in “Variant replacement” have also been realized in Variant a (in this case the length and Ir of the LINE 7-6). 7. Call the data input dialog of LINE 8-7 by double clicking the line. 8. Modify the data of the resistance.
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Fig. 1.63 Realize modifications for Variant a
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9. Activate Variant b. As you may notice, the Variant a can still be activated, because the two open variants are not depending from each other. 10.For this Variant b, you can introduce a compensation to LINE 8-7.
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Fig. 1.64 Realize modifications for Variant b
11.Activate “Variant additional” 12.Draw a new line from node FIVE to SEVEN and enter its data.
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Fig. 1.65 Introduce a new line for “Variant additional”
Create and assign a Topology Data File Topology data, such as the state of logical switches in the whole network, may be saved to a Topology Data File. To define different topology cases of a network, several variants could be defined with exactly the same characteristics but with a different topology data file. In the following we'll create such a topology data file by saving a modification of the state of a few logical switches in our example network. 1. Activate “Variant replacement” 2. Change the topology. In this case you may open the logical switches of a transformer. 3. Save the topology with "File - Export - Topology Data", using the name Topology1.
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Fig. 1.66 Create a topology file
4. Deactivate and activate again the “Variant replacement” but don't save it, because the topology modifications shouldn't be saved directly to the variant, but only in the topology file. Now the logical switches are closed again. 5. We now want to assign the topology file to the “Variant replacement”. Make a right-mouse-button click on the symbol of “Variant replacement” to call the popup menu, where you choose Properties. The same is possible by double-clicking the symbol of “Variant replacement”.
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6. The Variant Properties dialog appeared. 7. Press the respective button for choosing a "Topology Data File". 8. Look for the topology file and select it. 9. Open the topology file. 10.Press the OK button to finalize.
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Fig. 1.68 Assign the topology file to “Variant replacement”
Create and assign a Load Data File Data, such as the power to be consumed by a load or the power to be produced by a generator, may be saved to a Load Data File. To define different loading cases of a network, several variants could be defined with exactly the same characteristics but with a different load data file. In the following we'll create such a load data file by saving a modification of the operational active power of a generator. 1. By double-clicking the generator, call its data input dialog. 2. Change the operational data of the generator and save this modification to a "Load Data File” with "File – Export – Load Data".
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Fig. 1.69 Change Load data
3. Call the Variant Properties dialog by double clicking the symbol of “Variant replacement”. 4. Look for the Load Data File. 5. Open the Load Data File. 6. Finalize by pressing the OK button.
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Fig. 1.70 Assign the load data file to “Variant replacement”
You mustn't save the “Variant replacement” after these modifications, but you need to save the project. So the best way to do is, to first deactivate the variant without saving it and then you may save the project. In general be careful that you don't save the variant, when you changed Load or Topology data, which only should be contained in the Load and the Topology Data File. Now the Variant 1 includes a Load Data File and a Topology Data File. When the variant is opened, also these two data files are loaded. In the same manner you may assign the same or other Load and Topology Data File to the other variants.
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Load Flow Calculation In this chapter you will learn how to perform a load flow calculation on a small network and how to get the desired results. Open the project 1. Load the Load Flow example network. 2. Call the Load Flow Parameter dialog.
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Fig. 1.71 Adjustment of Load Flow calculation parameters
Adjust the calculation parameters 3. Select the calculation method. 4. You may change the maximum number of iterations. Default are 20 iterations. 5. Define if the on-load tapchanging transformers shall be regulated automatically during the load flow calculation. 6. You may choose a result-file *.rlf, which can be opened with a text editor or Excel. 7. Use the Reference tab to edit the reference loading for elements and the reference minimum and maximum voltage. 8. If you want to work with Area/Zone Control, use the respective tab to define the transactions. 9. Press the OK button to save the change and to quite the Parameter dialog.
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Fig. 1.72 Load Flow Parameters
Choose the result variables 10.For the results showed in the single line diagram, you can choose the variables to be displayed. This can be done now or after the calculation. Open the Diagram Properties dialog. 11.Choose the Load Flow tab. 12.Select the variables to be displayed in the single line diagram for nodes and elements. This selection doesn’t have any influence on the result tables. The result tables will contain all variables. 13.Define the units and number of digits for the result variables and decide if you want to see only the load flow results or at the same time the results of the last short circuit calculation.
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Fig. 1.73 Result variables
Perform the calculation 14.You may now perform the load flow calculation
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Fig. 1.74 Load Flow Calculation
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15.The results can be analyzed directly in the single-line diagram. If additional variables should be displayed, proceed as mentioned in step 10. It’s not necessary to repeat the calculation. 16.Use the zoom buttons to get a better view of the result boxes. 17.The network elements and nodes may be colored depending on the results. In this example the node became red because the voltage is below the minimum reference.
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Fig. 1.75 Analyzing the results
18.Use the Diagram Properties dialog (Edit – Diagram Properties) to define the coloration of the network depending on the network characteristics or the calculation results (tab Colors and Color Ranges).
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Fig. 1.76 Coloration of the network
Analyse the results using the result tables 19.Choose “Show Results” to get the results presented in tables. 20.You may get tables for a summary, the nodes, the elements or all results. 21.There is still the possibility to export the results in a file if this option was not activated in the “Load Flow – Parameters” dialog.
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Fig. 1.77 Result Tables
Analyze specific results 22.If you wish to display only the results of specific elements and nodes either in the single line diagram or in the result tables, you may use the “Select Results” option to select these elements.
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Fig. 1.78 Result output only for certain elements and nodes
23.To make sure that the results will be displayed in the single line diagram accordingly to this selection table, you need to activate this option in the “Edit – Diagram Properties – Load Flow” tab. 24.To make sure that the results will be displayed in the result tables accordingly to this selection table, you need to activate this option in the “Analysis – Load Flow – Show Results” dialog.
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Fig. 1.79 Result output for all elements and nodes or according to list
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Short Circuit Calculation In this chapter you will learn how to perform a short circuit calculation on a small network and how to get the desired results. Open the project 1. Load the Short Circuit example network. 2. Call the Short Circuit Parameter dialog.
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Fig. 1.80 Adjustment of Short Circuit calculation parameters
Adjust the calculation parameters 3. Select the fault type. 4. Choose the calculation method. 5. Enter a fault distance if you want to display the results as well of neighbor nodes of the fault location. 6. Possibly you need to adapt the calculation method depending parameters, according to your needs. 7. You may choose a result-file *.rsc, which can be opened with a text editor or Excel. 8. Define the reference for maximum loading of elements.
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Fig. 1.81 Short Circuit Parameters
Select the faulted nodes 9. Select the “Faulted nodes” tab in the Short Circuit Parameters. 10.Select the nodes which should be faulted und move them to the other table with the arrow button.
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Fig. 1.82 Select faulted nodes
Select faulted lines 11.Select the “Faulted lines” tab in the Short Circuit Parameters. 12.Select the lines which should be faulted und move them to the other table with the arrow button. 13.Insert the distance where the fault takes place, in % from the “From node”.
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Fig. 1.83 Select faulted lines
Define special faults 14.Select the “Special fault” tab in the Short Circuit Parameters. 15.Insert new fault descriptions. 16.Define the node numbers and their phases, between which the fault takes place. 17.Assign the node numbers to the faulted network nodes.
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Fig. 1.84 Define special faults
Choose the result variables 18.For the results showed in the single line diagram, you can choose the variables to be displayed. This can be done now or after the calculation. Open the Diagram Properties dialog. 19.Choose the Short Circuit tab 20.Select the variables to be displayed in the single line diagram for nodes and elements. This selection doesn’t have an influence on the result tables. The result tables will contain all variables. 21.Define the units and number of digits for the result variables and decide if you want to see only the short circuit results or at the same time the results of the last load flow calculation.
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Fig. 1.85 Result variables
Perform the calculation 22.You may now perform the short circuit calculation
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Fig. 1.86 Short Circuit Calculation
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23.The results can be analyzed directly in the single-line diagram. If additional variables should be displayed, proceed as mentioned in step 18. It’s not necessary to repeat the calculation. 24.Use the zoom buttons to get a better view of the result boxes.
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Fig. 1.87 Analyzing the results
Analyse the results using the result tables 25.Choose “Show Results” to get the results presented in tables. 26.You may get tables for all fault currents, only the currents at fault locations or the node voltages. 27.There is still the possibility to export the results in a file if this option was not activated in the “Short Circuit – Parameters” dialog.
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Fig. 1.88 Result Tables
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Transient Stability Analysis In this chapter you will learn how to perform a simulation with the Transient Stability module on a small network and how to get the desired results. Open the project 1. Load the Transient Stability example network.
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Fig. 1.89 Open the project
Enter Dynamic Data 2. Enter the Dynamic Data of the synchronous machines in the data input dialog.
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Fig. 1.90 Dynamic data of synchronous machine
3. Enter the saturation data of the synchronous machines.
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Fig. 1.91 Saturation data of synchronous machine
Enter control circuits CCT’s 4. Click on the CCT-button 5. Click in the diagram near of a synchronous machine to past the CCT. 6. A CCT dialog appears. Enter a name for this CCT. 7. Press the OK button.
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Fig. 1.92 Enter a CCT
8. A new diagram for the design of the CCT appeared.
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Fig. 1.93 Diagram for the design of the CCT
Design the block diagram for an AVR 9. Switch the Insert menu to a Function Block Menu.
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Fig. 1.94 Use of the Function Block Menu
10. Choose an Input-Block. 11. Make a mouse click in the diagram, where you wish to place the block.
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12. A properties dialog of the entered block appears. Enter the name of the block. 13. Select the variable. In this case, for an AVR, we choose the bus voltage magnitude. 14. Press the button and choose the respective node (BUS 1) from a list. 15. Close the window, pressing OK.
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Fig. 1.95 Enter function blocks
16.The Input Block has been pasted in the diagram.
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Fig. 1.96 An Input block has been entered
17.Choose a Sum-block. 18.Click in the diagram. The properties-dialog appears. 19.Enter a name. 20.Enter the constants and close the window with OK.
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Fig. 1.97 Enter a Sum block
21.Choose a Source-block for the reference voltage.
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22.Place it in the diagram. 23.Enter the name and the source constant.
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Fig. 1.98 Enter a Source block
24.Select the Source-block and turn it with the rotate buttons. 25.Use the link to interconnect the function blocks.
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Fig. 1.99 Interconnection of the function blocks with a link 1-92
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26.Build the rest of the control circuit in the same manner. 27.Build control circuits for other generators. Function blocks and control circuits may be copied from one diagram to the other.
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Fig. 1.100 Complete the control circuit (CCT)
Adjust the calculation parameters 1. Choose the parameter menu for transient stability.
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Fig. 1.101 Choose the parameter menu
2. Enter the simulation time. 3. You may choose a synchronous machine as reference for the rotor angle. 4. You have the possibility to change the step length and iteration data, but try first with the default values.
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Fig. 1.102 Adjust the simulation parameters
5. Use the Disturbances tab to define the disturbances during the transient sequence. 6. The disturbance with the sign ! is active for the following simulation. 7. You may edit the disturbance by double click or with the respective button.
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Fig. 1.103 Select a disturbance
Enter the disturbance data 8. In this case we want to add an initial load of 10% to a static load. 9. Pick the element to which the disturbance should be applied and the time, when the disturbance has to occur. 10.Use the respective buttons to add, remove or update the disturbance entries.
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Fig. 1.104 Define disturbances
Define the Screen Plots 11.Use the Screen Plots tab to define the variables, which shall be displayed on the screen or saved to a file. 12.The variables with a chart symbol will be displayed as screen plots during the simulation. 13.The variables with a disk symbol will be saved to a file and may be used to draw charts after the simulation. 14.Press Edit to edit a screen plot entry.
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Fig. 1.105 Screen Plots to display on the screen or to save to a file
15.Define the element and the variable for which you want to draw a screen plot or a chart. 16.Use the respective buttons to add, remove or update the screen plot entries.
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Fig. 1.106 Define Screen Plots
Simulation and Analysis 1. Run a Transient Stability simulation.
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Fig. 1.107 Run a Transient Stability simulation
2. A Screen Plot appears and the curves of the selected variables are being drawn. Below the diagrams, a event report is displayed.
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Fig. 1.108 Screen plot at the end of the simulation
3. The Screen Plot shows you the selected variables during the whole simulation process. The user has the possibility to break, to continue or even to exit the simulation process.
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Fig. 1.109 Options to break, continue or exit the simulation
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4. Close the Screen Plot and choose Graphical Results for Transient Stability. If there were never defined any charts for this project, one empty chart will appear.
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Fig. 1.110 Call the Graphical Results
5. You can define several charts. Every chart represents a graphical sheet and may consist of one or more subcharts. To start, add a subchart in your existing chart. 6. In the appearing dialog, enter a name for the curve and select the values for the X-Axis and Y-Axis. 7. Press the OK-button to get to the next dialog.
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Fig. 1.111 Select the variables for a curve
8. Enter a name for the chart. 9. Select the curve's drawing settings. 10.If there are more than one curve entries, the displayed drawing settings are only valid for the marked curve. 11.To add curves in the same subchart or to edit or delete existing curves, use the corresponding buttons. 12.Switch to the Subchart Settings tab.
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Fig. 1.112 Define all the curves to be displayed in one subchart
13.Select an axis. 14.Adjust the properties for the selected axis. 15.You have the possibility to show a legend in the subchart. 16.Press OK to finalize.
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Fig. 1.113 Adjust the subchart settings
17.The defined curves are drawn in the subchart.
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Fig. 1.114 A chart with one subchart and one curve
18.Define as many charts, subcharts and curves as you wish. They need to be defined only once for the project. After each simulation the same curves will be drawn in the graphical results. Remember that only variables, which have been declared as variables to be saved to a file, in the "Transient Stability – Parameter - Screen Plot" menu, are available for presentation in these charts.
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Fig. 1.115 Define several charts and subcharts
19.To see the Transient Stability results listed in a table choose Result Table(Elements).
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Fig. 1.116 Have a look at the presentation of the results in the Result Table
20.Look at the results in the Result table.
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Fig. 1.117 Transient Stability results listed in a table
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Interfaces to NEPLAN NEPLAN has several interfaces to external applications: • Import/Export through ASCII file • Export to data base • Result data base • Clipboard • DXF-files • Raster-Graphics (e.g. BMP, PCX, TIFF, etc.) • DVG-Format (Format der Deutschen Verbundgesellschaft) Import/Export There are two import/export files for external programs, such as MS-Excel, the EDT- and the NDT-file. The EDT-file contains topological and electrical data of the elements, the NDT-file contains the topological and loading data of the nodes. The file structure of the import/export files is given in the appendix (see "Appendix"). If data is imported without graphic, then it is possible to generate the graphic of the network automatically by the NEPLAN "Auto-Layout" function. Topology/Loading-data files The topology and the loading data of a network may be saved in the ZDB-file (topology) and in the NDB-file (loading). The ZDB- and the NDB-file are used to define variants. To each variant a Load Data File and a Topology Data File can be assigned (see "Edit – Variant Properties" in the chapter "Menu Options"). Clipboard The diagram can be exported onto the clipboard. The clipboard data can be imported by an external program, such as a word processing program. DXF-Files DXF-files can be imported. All diagrams are identified and displayed. The user can select the diagrams to be imported from a list. The imported drawing can be additionally scaled. The imported diagrams are managed by the program in different graphic layers. The imported drawing can be changed.
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Cadastre and Raster-Graphics Files (BMP, PCX, TIFF) Raster graphics files (BMP, PCX, TIFF, etc.) can be imported in any diagram. It is possible to import a raster graphic (e.g. PCX) as a cadastre. The cadastre can be used as background for the NEPLAN network data. The cadastre can be calibrated to use real world coordinates.
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Tips from the Practice Important tips from the practice are given here.
Asymmetrical Network Structure Representation of an Asymmetrical Line It is recommended to enter lines in a compact way. A 3-phase line from node A to B can theoretically be entered as three single phase lines, which are coupled between each other. In this way the program will work not only with the current circuit resp. the series impedance matrices but also with the coupling matrices. This increases the calculation effort. The better way is to represent the 3-phase line with one 3-phase line. The same is valid for a 2-phase line.
Load Flow Divergence using PV-Nodes • When using PV-nodes the Newton-Raphson method should be used. The user has to take care that no disconnect or load switches as well as short lines will be connected to the PV-node, because of numerical problems. If disconnect and load switches are connected to PV-nodes it is advisable to reduce them during calculation. If for example a generator is connected to a bus bar through disconnect switches (one open, one closed), the generator node should be marked as reducible (see "Node Data Input" in chapter "Element Data Input and Models"). • When using the current iteration method the same is valid. The convergence can be additionally influenced by the accelerating factor (see "Calculation Parameters (LF)" in chapter "Load Flow"). Probably the value must be reduced until 0.05 to obtain convergence. The convergence criteria should also be reduced.
Switching Topology or Connecting Motors
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• If the motor starting module is not available and the user like to make voltage drop calculation when switching the topology or connecting motors, the network impedance (network feeder) must be represented by a line. In the normal load flow calculation the internal network impedance (Sk", Un) is not considered.
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Element Data Input and Models Data Input Dialogs of Network Elements The element data for the power system calculation are entered with the help of data input dialogs. The dialog appears after having entered the element graphically. The entered data will be saved into a common database (project file), which will be used from all calculation modules. The modules read only the data, which is necessary to perform the specific calculation. The data not used will be over read. At the bottom of the data input dialog the following push buttons are available: Copy and Paste
Copies the data from an element into an internal buffer. While inserting the data for another element, it is possible to get these data from the buffer with the option "Paste". The data are transferred to the data input dialog of this element.
Library
For some elements it is possible to select a library containing predefined standard data. This library can be built up in the menu Libraries.
Export
It’s possible to export the data of the element to the actual library by pressing the Export button. A type name has to be entered before or a type has to be chosen in the type option of the Params tab.
OK
The edited data will be saved. A new element will be inserted.
Cancel
The edited data will not be changed. A new element will not be inserted.
Help
The online Help will be called.
Tools
It’s possible to use background colors for the data fields of the data input dialog, depending on if the respective data is necessary for a certain calculation. A different color may be chosen for mandatory fields and preference fields.
Classification of Data in the Data Input Dialog
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Element Data Input and Models
In the following sections the parameters to be entered in the Data Input Dialogs will be described. For every parameter there is an indication for what kind of calculation the input is needed. The indication is given by: L
Load flow, Optimal Power flow, Contingency Analysis, Voltage Stability
S
Short circuit, Distance protection
M
Motor starting
H
Harmonic frequency analysis
P
Distance protection analysis
D
Dynamic Analysis, Small Signal Stability
R
Reliability
O
Selectivity Analysis
If there is a parentheses (), it means, that this parameter is used for all NEPLAN-modules. All parameters used for short circuit analysis are necessary also for selectivity analysis, because the short circuit simulation makes part of the selectivity analysis.
Element - Info Every element has an Info tab, which gives general information about the element. The type of information is nearly the same from one element to the other, that’s why this tab is explained here and won’t be mentioned anymore in the elements data input chapters. Name
Name of element. When the Input dialog of an element or node is open for the first time after the entry of this element, there is a "…"-button beside the name field. If you want to represent an already existing element in the project again, then press this button and choose the respective element.
ID
()
ID-number of element (generated by NEPLAN).
Partial Network ID
()
ID-number of the partial network (generated by NEPLAN).
Description Area 4-2
Description of element. ()
Indicates the area to which the element belongs. New NEPLAN User's Guide V5
Element Data Input and Models
areas may be defined in "Edit – Variant Properties". Zone
()
Projected Connected nodes
Indicates the zone to which the element belongs. New zones may be defined in "Edit – Variant Properties". Indicates, if the line is projected or if it exists already.
()
From: Name of starting node. To: Name of ending node. Checkbox ON/OFF: Connects or disconnects the element at the respective node.
For some elements the user has the possibility to choose the phases, so it’s possible to define an asymmetrical element. This is done by the following option: Phases
()
Indicates the phasing of the element. Possible values are: - L1L2L3N: Symmetrical element - L1N: Single phase element, phase L1 - L2N: Single phase element, phase L2 - L3N: Single phase element, phase L3
If an element doesn’t include this option, there exists an other similar element for asymmetrical applications, which has to be entered (e.g. asymmetrical line).
Element - Reliability Every element has a Reliability tab for the data input used in Reliability Analysis. This module is still in development, therefore these parameters will be explained later.
Element - User Data Every element has a User Data tab. The user may define his own variables, which enter in a table list. The values of the variables may be modified directly in the table list. If the checkbox of a variable is checked, the variable will be displayed in the single line diagram. The variables are only for information and documentation purposes and do not enter in any calculations. New Variable: Name NEPLAN User's Guide V5
Name of variable to enter in the table list.
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Element Data Input and Models
New Variable: Type
Type of variable to enter in the table list.
Add Variable
Press this button to add a variable to the table list.
Remove Variable
Press this button to remove a variable from the table list.
Element - More… Frequency dependence In general the resistances and the inductances in the equivalent circuits of the network elements are frequency-dependent. The program permits to consider the frequency dependency in three different manners: • according to an exponential function • according to a table R(f) and L(f) • according to a locus diagram
Frequency Dependency According to an Exponential Function
The frequency dependency of a resistance resp. of an inductance is according to the following formulas: Br f R( f ) = Rn ⋅ 1 + Ar ⋅ − 1 fn
f L( f ) = Ln ⋅ Al ⋅ fn
Bl
It means: R(f), L(f): Rn, Ln: Ar, Br, Al, Bl: f: Fn: 4-4
resistance resp. inductance at frequency f nominal value of the resistance resp. inductance at nominal system frequency Factors Frequency nominal system frequency NEPLAN User's Guide V5
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The figures 4.1 and 4.2 show the characteristic of R(f) resp. L(f) according to the above formulas. This frequency dependency is only defined for frequencies above the nominal system frequency.
20.0 R(f)/Rn 10.0
0.0 0.0
500.0 1000.0 frequency f [Hz]
Fig. 4.1 Frequency dependency of a resistance
1.0 L(f)/Ln 0.5
0.0 0.0
500.0 1000.0 frequency f [Hz]
Fig. 4.2 Frequency dependency of an inductance
Frequency Dependency According to a Table R(f) and L(f)
It is possible to enter the frequency dependency of R and L tabulated. It is meaningful to give the values for the k-th harmonic fk as based values R(fk)/Rn and L(fk)/Ln. The base are the values Rn, Ln for nominal system frequency fn. A pair of values fk and R(fk)/Rn resp. fk and L(fk)/Ln are NEPLAN User's Guide V5
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Element Data Input and Models
designated as a foothold. For frequencies not corresponding with the frequencies of a foothold a linear interpolation will be done.
Frequency Dependency According to a Locus Diagram
Arbitrary impedance curves can be represented by a locus diagram. It is possible to reproduce given impedance curves (e.g. results of a measurement). For all frequencies fk the real value R(fk) and the imaginary value X(fk) of the impedance Z(fk) can be entered tabulated (R and X in series). These value groups (fk, R, X) are designated as footholds of the locus diagram. For frequencies not corresponding with the frequencies of a foothold, a linear interpolation will be done (separate for the real and the imaginary value). This kind of frequency dependency is only valid for the network elements "network feeder", shunts and loads. The elements of the equivalent circuits will be calculated exclusively by the values of the locus diagram and not by the formulas given for the element models.
Investment Analysis
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Station This chapter describes the parameters of the Data Input Dialog of a station. This element is not needed for calculations.
Station - Parameters Name
Station name.
Type
Station type
Municipality
Municipality, where the station has been built.
Location
Location of the station.
Protection
R
Protection concept in the station
This element is not needed for calculations. It is used to switch between different network layers.
Station-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Station-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Station-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Station-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The NEPLAN User's Guide V5
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description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
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Node This chapter describes the parameters of the Data Input Dialog of a node. Node-Parameters Name
Node name.
Area
()
Defines the area to which the element belongs.
Zone
()
Defines the zone to which the element belongs.
Node type
()
Node type. Following values are possible: - Bus bar - Sleeve - Special node - Main bus bar The thickness of a node in the diagram can be changed according to the here entered value (see menu option "Line Width" in chapter "Menu Options"). Otherwise the input value has no importance.
Dist. protection node
P
Indicates, if the node has to be considered, when making the automatic relay setting. If this option is checked, the node will be handled like a distance protection relay node.
Un
()
Nominal system voltage of node in kV.
Uset
LDR
Setting value in % of nominal voltage for this node. Input is only relevant, if the node will be regulated during calculation with a tap-changing transformer (see chapter "Load Flow").
Umin
LDR
Min. allowable node voltage in %. If the voltage will go below this limit during calculation, this value will be kept (only for Newton-Raphson method).
Umax
LDR
Max. allowable node voltage in %. If the voltage will go beyond this limit during calculation, this value will be kept (only for Newton-Raphson method).
f
SP
Frequency
Ipmax
SP
Max. allowable peak short circuit current of bus-bar in kA.
t dp
P
Tripping time in seconds of a primary protection, e.g. fuse in a distribution pole.
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Node-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Node-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Node-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Node-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
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DC Node This chapter describes the parameters of the Data Input Dialog of a node. DC Node-Parameters Name
Node name.
Area
()
Defines the area to which the element belongs.
Zone
()
Defines the zone to which the element belongs.
Un
()
Nominal system voltage of node in kV.
DC Node-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
DC Node-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
DC Node-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
DC Node-More… Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
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Element Data Input and Models
Line This chapter describes the parameters of the Data Input Dialog of a line and the corresponding line model. Line-Parameters Name
Name of element.
Type
Applicable only with a line library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Length
()
Length of the line in km or miles or 1000 feet (see Units).
Units
()
Units for the input values below. Possible values are: - Ohm/km: Ohm, µS, µF per km - Ohm/miles: Ohm, µS, µF per miles - Ohm/1000ft: Ohm, µS, µF per 1000 feet
R(1)
()
Positive sequence resistance in Ohm/km or see Units.
R(0)
SP
Zero sequence resistance in Ohm/km or see Units.
X(1)
()
Positive sequence reactance in Ohm/km or see Units.
X(0)
SP
Zero sequence reactance in Ohm/km or see Units.
C(1)
()
Positive sequence capacitance in µF/km or see Units.
C(0)
SP
Zero sequence capacitance in µF/km or see Units.
G(1)
()
Positive sequence conductance in µS/km or see Units.
Ir max
L
Maximum rated current in A. The loading of the line can be calculated according to Ir min or Ir max (see load flow calculation parameters).
Ir min
L
Minimal rated current in A. The loading of the line can be calculated according to Ir min or Ir max (see load flow calculation parameters).
T perm
SP
Max. permitted temperature in °C for the calculation of minimum short circuit currents. The default value is 80 °C.
Red. factor
L
Reduction factor. Ir will be corrected to: Ir min = red.fact. * Ir min; Ir max = red.fact. * Ir max
No. of lines () Q 4-12
Number of parallel lines between starting and ending node. Cross-section of the line in mm2 . A line can be NEPLAN User's Guide V5
Element Data Input and Models
displayed with different line width according to the cross section (see menu option "Line Width" in chapter "Menu Options"). Cable
Indicates, whether the line is a cable or not. The cables and the overhead lines can be displayed with different line types (see menu option "Edit – Diagram Properties Lines").
Overhead
Indicates, whether the line is overhead or not. The overhead lines and the cables can be displayed with different line types (see menu option "Edit – Diagram Properties -Lines").
Switchable
L
Indicates, if the line is switchable for calculation of optimal separation point.
Line-Sections This option is useful if the line consists of sections. In the Sections tab the line sections can be entered. With the corresponding push buttons the sections can be inserted, updated or deleted. The parameters of the sections can also be taken from a line library. In the table of the line section entries, the user can see all entered line sections. The input fields for the parameters are the same as in the Line-Params tab. The length and parameters of the whole line are calculated automatically with the entered line sections and they appear in the Params tab. These calculated parameters cannot be modified, because they represent a combination of the line sections parameters.
Line-Pylons The user has the possibility to calculate the parameters of an overhead line with the help of the Pylons tab in the line data input dialog. With this function, the parameters of one single line will be calculated by inserting the conductors characteristics and the arrangement data. To be able to enter the arrangement data, it’s necessary to choose one or more pylons. The respective pylons have to be entered before graphically from the Symbol Window (see chapter “Pylon” on page 4-33). If there are coupled lines, it is recommended to use the line-coupling editor, which calculates the coupling impedances and the parameters of all the considered lines (see chapter “Line-Coupling” on page 4-28). Phase conductors Conductors per
Bundle conductors can also be entered and calculated. The
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Element Data Input and Models
bundle
number of the conductor elements can be specified here. The values are 1..4.
Distance
Distance of the conductor elements in cm. Typical value: 40 cm.
Diameter
Diameter of a conductor element in cm.
R
Specific resistance in Ω/km of the phase conductors at 20° Celsius.
Sag
Sag h of the conductors in m. For the parameter calculation the y-values are corrected as follows: ynew = yinp - 0.7·h.
Pylon data Insert
A pylon, entered before, may be selected from a list. It’s possible to choose various pylons and for everyone, the arrangement data has to be entered.
Delete
A pylon may be removed from the list. The respective arrangement data will get lost.
x (L1)
x-coordinate in m of phase conductor L1 related to the pylon (see remark below).
y (L1)
y-coordinate in m of phase conductor L1 from earth.
x (L2)
x-coordinate in m of phase conductor L2 related to the pylon.
y (L2)
y-coordinate in m of phase conductor L2 from earth.
x (L3)
x-coordinate in m of phase conductor L3 related to the pylon.
y (L3)
y-coordinate in m of phase conductor L3 from earth.
Circuit data calculation Twisted
Indicates, if the phase conductors of the overhead line are twisted or not. The symmetrical ß-twisting will be assumed (cyclical transposition of the phase conductors at 1/3 and 2/3 of the line). The input is valid for each line (phase system).
rho E
Earth resistivity in Ωm. Typical values are: Rock: greater 3000 Ωm; Stone floor, Slate: 1000..3000 Ωm; gneiss, granite: 10000 Ωm; dry sand, gravel: 200..1200 Ωm; wed sand, chalky soil: 70..200 Ωm; field: 50..100 Ωm; clay, loam: 100..50 Ωm; marshy soil, alluvial land: smaller 20 Ωm. Default value: 100 Ωm.
Calculate 4-14
The line parameters will be calculated based on the data NEPLAN User's Guide V5
Element Data Input and Models
entered in the Pylons tab. The result will be indicated in the Params tab. Earth conductor Active
Defines, whether an earth conductor exists or not. If it is active, it will be considered for the calculation.
R
Specific resistance in Ω/km of the earth conductor at 20° Celsius.
Diameter
Diameter of the earth conductor in cm.
Permeability
Relative permeability µ of the earth conductor. Typical values are: copper, aluminium conductors: µ=1.0; aluminium/steel conductors with one layer aluminium: µ~5..10; aluminium/steel conductors with cross section ratio greater equal 6: µ~1.0; steel conductors: µ=25.0 .
X
x-coordinate in m of the earth conductor related to the pylon (see remark below).
Y
y-coordinate of the earth conductor in m from earth.
If a phase does not exist its input data remains zero.
Remark to the Coordinate Input: Y axis
Earth conductors Phase conductors
X axis 0
Fig. 4.1 Pylon arrangement Earth or phase conductors, which are left of the pylon, must be entered with negative x-coordinate. Conductors, which are right of the pylon, must be entered with positive x-coordinate.
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Element Data Input and Models
Line-Compensation Name
Name of element
For the primary and the secondary side of the line, the following parameters have to be introduced, if there is a line compensation: P(1)
()
Active power of positive sequence
Q(1)
()
Reactive power of positive sequence
P(0)
SP
Active power of zero sequence
Q(0)
SP
Reactive power of zero sequence
Active
()
The user can define, which portion in % of the compensation is active.
Line-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Line-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Line-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Line-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. 4-16
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Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Line Loads…
For the description of the parameters for Line Loads see chapter “Line Load” on page 4-146.
Recommended Values for Line Zero Sequence Data: The zero sequence data of a line are dependent on the line type (cable or overhead line), of its structure and of its laying (cable). In reference / 3 / recommended values are shown.
Description of the Model (Line) Y11
R
X
Y22
Ycomp1
Ycomp2 B11
G11
G22 B22
Fig. 4.2 Model of a line
The model parameters of the positive and zero sequence are calculated as follows: Positive sequence
Zero sequence
R = R(1) · length X = X(1) · length B = 2·PI·f·C(1) · length G11 = G / 2
R = R(0) · length X = X(0) · length B = 2·PI·f·C(0) · length G11 = 0.0
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B11 = B / 2 G22 = G / 2 B22 = B / 2 Ycomp1 = G1s + jB1s Ycomp2 = G2s + jB2s Y11 = G11 + j·B11 + Ycomp1 Y22 = G22 + j·B22 + Ycomp2
B11 = B / 2 G22 = 0.0 B22 = B / 2 Ycomp1 = G1s + jB1s Ycomp2 = G2s + jB2s Y11 = G11 + j·B11 + Ycomp1 Y22 = G22 + j·B22 + Ycomp2
If the input values P1(1,0), Q1(1,0), P2(1,0), Q2(1,0) unequal zero, it is: G1s = (P1*P1 + Q1*Q1) / (P1*Un²) B1s = (P1*P1 + Q1*Q1) / (Q1*Un²) G2s = (P2*P2 + Q2*Q2) / (P2*Un²) B2s = (P2*P2 + Q2*Q2) / (Q2*Un²)
G1s = (P1*P1 + Q1*Q1) / (P1*Un²) B1s = (P1*P1 + Q1*Q1) / (Q1*Un²) G2s = (P2*P2 + Q2*Q2) / (P2*Un²) B2s = (P2*P2 + Q2*Q2) / (Q2*Un²)
Further it is: L = X / (2·PI·f) R_T = R[1+0.0039·(T-20)]
R_T = R[1+0.0039·(T-20)]
Meaning: f T R_T Ycomp1 Ycomp2
System frequency Max. permitted temperature Reactance at temperature T Admittance of the line compensation on side 1 Admittance of the line compensation on side 2
In case the minimum short circuit current is calculated R_T will be taken instead of R (by 20° C). Remark: C(1) res. Y(1) are not used in a short circuit calculation according to IEC.
Model for Harmonic Analysis A distributed parameter line model is used for modeling the line. The series and shunt elements are calculated from the exact line equation for each frequency. Only the positive sequence is considered. The series impedance Z12 between the nodes 1 and 2 of the line is calculated as: 4-18
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Z12 = ZW ( f ) ⋅ sinh( g ( f ))
The shunt impedances are: Z1 ( f ) = Z 2 ( f ) = ZW ( f ) ⋅ coth( g ( f ) / 2 )
The values are for the equation:
U =Z⋅I
ZW means the natural impedance and g means the propagation constant of the line. Neglecting the resistant to earth, the following formulas are valid for ZW and g: ZW ( f ) =
R1 ( f ) + j ⋅ 2 ⋅ π ⋅ f ⋅ L1 ( f ) G1 + j ⋅ 2 ⋅ π ⋅ f ⋅ C1
g ( f ) = ( R1 ( f ) + j ⋅ 2 ⋅ π ⋅ f ⋅ L1 ( f )) ⋅ (G1 + j ⋅ 2 ⋅ π ⋅ f ⋅ C1 ) ⋅ l
It means: F L1(f) R1(f) C1 G1 L
arbitrary frequency frequency dependent inductance of line in Henry/km frequency dependent resistance of line in Ohm/km frequency independent capacitance of line in µF/km frequency independent conductance of line in µS/km length of line in km.
If the frequency dependency of X1 and/or R1 are given, the values L1(f) and/or R1(f) are calculated from X1 and R1.
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Asymmetrical Line This chapter describes the parameters of the Data Input Dialog of an asymmetrical line and the corresponding model. Asymmetrical Line - Parameters Name
Name of element.
Type
Applicable only with a line library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Length
()
Length of the line in km or miles or 1000 feet (see Units).
Units
()
Units for the input values below. Possible values are: - Ohm/km: Ohm, µS, µF per km - Ohm/miles: Ohm, µS, µF per miles - Ohm/1000ft: Ohm, µS, µF per 1000 feet
Phase () values for R
Phase values for resistance R in Ohm/km or see Units.
()
Phase values for reactance X in Ohm/km or see Units.
Phase () values for C
Phase values for capacitance C in µF/km or see Units.
Ir max
L
Maximum rated current in A. The loading of the line can be calculated according to Ir min or Ir max (see load flow calculation parameters).
Ir min
L
Minimal rated current in A. The loading of the line can be calculated according to Ir min or Ir max (see load flow calculation parameters).
T perm
SP
Max. permitted temperature in °C for the calculation of minimum short circuit currents. The default value is 80 °C.
Red. factor
L
Reduction factor. Ir will be corrected to: Ir min = red.fact. * Ir min; Ir max = red.fact. * Ir max
Phase values for X
No. of lines () Q
4-20
Number of parallel lines between starting and ending node. Cross-section of the line in mm2 . A line can be displayed with different line width according to the cross NEPLAN User's Guide V5
Element Data Input and Models
section (see menu option "Line Width" in chapter "Menu Options"). Cable
Indicates, whether the line is a cable or not. The cables and the overhead lines can be displayed with different line types (see menu option "Edit – Diagram Properties Lines").
Overhead
Indicates, whether the line is overhead or not. The overhead lines and the cables can be displayed with different line types (see menu option "Edit – Diagram Properties -Lines").
Switchable
L
Indicates, if the line is switchable for calculation of optimal separation point.
Asymmetrical Line - Pylons The user has the possibility to calculate the parameters of an overhead line with the help of the Pylons tab in the line data input dialog. With this function, the parameters of one single line will be calculated by inserting the conductors characteristics and the arrangement data. To be able to enter the arrangement data, it’s necessary to choose one or more pylons. The respective pylons have to be entered before graphically from the Symbol Window (see chapter “Pylon” on page 4-33). If there are coupled asymmetrical lines, it is recommended to use the asymmetrical line - coupling editor, which calculates the coupling impedances and the parameters of all the considered lines (see chapter “Asymmetrical Line-Coupling” on page 4-28). Phase conductors Conductors per bundle
Bundle conductors can also be entered and calculated. The number of the conductor elements can be specified here. The values are 1..4.
Distance
Distance of the conductor elements in cm or inch. Typical value: 40 cm.
Diameter
Diameter of a conductor element in cm or inch.
R
Specific resistance in Ω/km or Ω/miles or Ω/1000ft of the phase conductors at 20° Celsius.
Sag
Sag h of the conductors in m or in feet. For the parameter calculation the y-values are corrected as follows: ynew = yinp - 0.7·h.
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Element Data Input and Models
Pylon data Insert
A pylon, entered before, may be selected from a list. It’s possible to choose various pylons and for everyone, the arrangement data has to be entered.
Delete
A pylon may be removed from the list. The respective arrangement data will get lost.
x (L1)
x-coordinate in m or feet of phase conductor L1 related to the pylon (see remark below).
y (L1)
y-coordinate in m or feet of phase conductor L1 from earth.
x (L2)
x-coordinate in m or feet of phase conductor L2 related to the pylon.
y (L2)
y-coordinate in m or feet of phase conductor L2 from earth.
x (L3)
x-coordinate in m or feet of phase conductor L3 related to the pylon.
y (L3)
y-coordinate in m or feet of phase conductor L3 from earth.
Circuit data calculation Twisted
Indicates, if the phase conductors of the overhead line are twisted or not. The symmetrical beta-twisting will be assumed (cyclical transposition of the phase conductors at 1/3 and 2/3 of the line). The input is valid for each line (phase system).
rho E
Earth resistivity in Ωm. Typical values are: Rock: greater 3000 Ωm; Stone floor, Slate: 1000..3000 Ωm; gneiss, granite: 10000 Ωm; dry sand, gravel: 200..1200 Ωm; wed sand, chalky soil: 70..200 Ωm; field: 50..100 Ωm; clay, loam: 100..50 Ωm; marshy soil, alluvial land: smaller 20 Ωm. Default value: 100 Ωm.
Calculate
The line parameters will be calculated based on the data entered in the Pylons tab. The result will be indicated in the Params tab.
Earth conductor Active
Defines, whether an earth conductor exists or not. If it is active, it will be considered for the calculation.
R
Specific resistance in Ω/km of the earth conductor at 20° Celsius.
Diameter
Diameter of the earth conductor in cm.
Permeability
Relative permeability µ of the earth conductor. Typical values are: copper, aluminium conductors: µ=1.0; aluminium/steel conductors with one layer aluminium:
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µ~5..10; aluminium/steel conductors with cross section ratio greater equal 6: µ~1.0; steel conductors: µ=25.0 . X
x-coordinate in m or feet of the earth conductor related to the pylon (see remark below).
Y
y-coordinate in m or feet of the earth conductor from earth.
If a phase does not exist its input data remains zero.
Remark to the Coordinate Input: Y axis
Earth conductors Phase conductors
X axis 0
Fig. 4.3 Pylon arrangement Earth or phase conductors, which are left of the pylon, must be entered with negative x-coordinate. Conductors, which are right of the pylon, must be entered with positive x-coordinate.
Asymmetrical Line - Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Asymmetrical Line - Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
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Asymmetrical Line - User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Asymmetrical Line - More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (Asymmetrical Line) Asymmetrical lines are entered in the phase system, L1, L2, L3 with or without earthing conductor. The line will be described with two symmetrical matrices as follows: U L1 Z L1− L1 U Z L 2 = L1− L 2 U L3 Z L1− L3 U N Z L1− N I L1 YL1− L1 I Y L 2 = L1− L 2 I L 3 YL1− L3 I N YL1− N
Z L1− L 2 Z L 2− L 2 Z L 2− L3 Z L 2− N YL1− L 2 YL 2 − L 2 YL 2 − L3 YL 2− N
Z L1− L3 Z L 2− L3 Z L 3− L 3 Z L 3− N YL1− L3 YL 2− L3 YL3− L3 YL 3− N
Z L1− N I L1 Z L 2− N I L 2 • Z L 3− N I L 3 ZN −N I N
with Z = R + jX
YL1− N U L1 YL 2 − N U L 2 • YL 3− N U L 3 YN − N U N
Corresponding to the line phasing, elements in the matrix can be set to zero. No values for these elements should be entered in the input mask. For example, for a single phase line L1N only the elements for L1-L1, L1-N and NN must be entered.
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If there is no earthing conductor the values can be set to zero. The impedance and admittance values can be calculated from the conductor arrangement in the Pylons tab. During the network calculation the neutral conductor will be reduced: UN = 0.0. The 4x4 matrices will become two 3x3 matrices. These matrices can be transformed into the symmetrical component system with the help of the transformation matrix [Z012] = [T]-1[ZL1L2L3]⋅[T]: 1 1 [T ] = 1 a 2 1 a
1 a with a = -0.5 + j0.5 * √3 a 2
Remark
It is recommended to enter lines in a compact way. A 3-phase line from node A to B can theoretically be entered as three single phase lines, which are coupled between each other. In this way the program will work not only with the current circuit resp. the series impedance matrices but also with the coupling matrices. This increases the calculation effort. The better way is to represent the 3-phase line with one 3-phase line. The same is valid for a 2-phase line. In case of a single phase or a two phase system with a neutral conductor (cable) and omitting all currents in earth, there are two ways to enter the data: ZL
ZN
1. Addition of ZL and ZN U L1 ( ZL + ZN ) U 0 L2 = U L 3 0 0 U N
0 0 0 0
0 0 0 0
2. Considering the neutral ZN 0 I L1 U L1 ZL U 0 0 I L 2 or L 2 = • U L 3 0 0 I L 3 0 I N U N ZN
0 0 0 0
0 ZN I L1 0 0 I L 2 • 0 0 I L3 0 − ZN I N
The first way is the better way and corresponds to the measurement of the impedances.
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DC Line This chapter describes the parameters of the Data Input Dialog of a line and the corresponding line model. DC Line - Parameters Name
Name of element.
Type
Applicable only with a DC-line library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Length
()
Length of the line in km or miles or 1000 feet (see Units).
Units
()
Units for the input values below. Possible values are: - Ohm/km: Ohm, µS, µF per km - Ohm/miles: Ohm, µS, µF per miles - Ohm/1000ft: Ohm, µS, µF per 1000 feet
R
()
Positive sequence resistance in Ohm/km or see Units.
L
()
Inductance in mH/km. Not used for steady state calculations.
Ir max
L
Maximum rated current in A. The loading of the line can be calculated according to Ir min or Ir max (see load flow calculation parameters).
Ir min
L
Minimal rated current in A. The loading of the line can be calculated according to Ir min or Ir max (see load flow calculation parameters).
DC Line - Sections Line sections are not allowed for DC lines.
DC Line - Pylons Line pylons are not considered for DC lines.
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DC Line - Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
DC Line - Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
DC Line - User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
DC Line - More… Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (DC Line) for steady state calculation RL
Fig. 4.4 Model of a DC line
RL = R*Length
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Line-Coupling To insert line-coupling data, first the line-coupling symbol has to be chosen in the symbol window and pasted to the lines, which are coupled together. If the coupling impedances and the line data are known, they directly can be entered in the line-coupling and the line data input dialog, respectively. There exists the possibility to calculate these data by entering the information about the conductors characteristics and the conductors arrangements data in the linecoupling data input. By pressing the button "Calculate" in the Impedances tab, the results will be written into the line-parameters and the line-couplingimpedances.
Coupling group A coupling group can consist of maximum 6 lines (systems). Name
Name of coupling group
Earth conductors
SP
By pressing the "…"-button the earth conductors of the coupling group may be chosen.
Phase conductors
SP
By pressing the "…"-button the phase conductors may be chosen for every system of the coupling group .
Coupling-Impedances The coupling impedances can be entered after having entered the coupled lines (systems). These data and the line parameters can also be calculated, if the arrangement data is known and entered in the Arrangement tab. For each coupling (e.g. 1-2: system 1 and system 2; 1-3: system 1 and system 3) the following data can be entered or calculated: R(1)
SP
Positive sequence mutual resistance in Ω/km or Ω/mile or Ω/1000ft.
X(1)
SP
Positive sequence mutual reactance in Ω/km or Ω/mile or Ω/1000ft.
Y(1)
SP
Positive sequence mutual admittance in µS/km or µS /mile or µS /1000ft.
R(0)
SP
Zero sequence mutual resistance in Ω/km or Ω/mile or Ω/1000ft.
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X(0)
SP
Zero sequence mutual reactance in Ω/km or Ω/mile or Ω/1000ft.
Y(0)
SP
Zero sequence mutual admittance in µS/km or µS /mile or µS /1000ft.
Length
SP
Length of mutual coupling lc in km or mile or 1000ft.
Calculation
By pressing the button Calculation, the Coupling Impedances and the line parameters will be calculated, based on the arrangement data.
Coupling-Conductors Earth conductor (Cond.1 – Cond.3) Diameter
Diameter of the earth conductor in cm.
R
Specific resistance in Ω/km or Ω/mile or Ω/1000ft of the earth conductors at 20° Celsius.
Sag
Sag h of the conductors in m or feet. For the parameter calculation the y-values are corrected as follows: Ynew = yinp - 0.7·h.
Phase conductors (System 1 – System 6) No. con. elem.
Bundle conductors can also be entered and calculated. The number of the conductor elements can be specified here. The values are 1..4.
Dist. con. elem.
Distance of the conductor elements in cm or inch. Typical value: 40 cm.
Diameter
Diameter of a conductor element in cm or inch.
R
Specific resistance in Ω/km or Ω/mile or Ω/1000ft of the phase conductors at 20° Celsius.
Sag
Sag h of the conductors in m or feet. For the parameter calculation the y-values are corrected as follows: Ynew = yinp - 0.7·h.
Coupling-Arrangement General Data
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Element Data Input and Models
Re
Earth resistivity in Ωm. Typical values are: Rock: greater 3000 Ωm; Stone floor, Slate: 1000..3000 Ωm; gneiss, granite: 10000 Ωm; dry sand, gravel: 200..1200 Ωm; wed sand, chalky soil: 70..200 Ωm; field: 50..100 Ωm; clay, loam: 100..50 Ωm; marshy soil, alluvial land: smaller 20 Ωm. Default value: 100 Ωm.
Permeab. µ
Relative permeability of the earth conductor. Typical values are: copper, aluminium conductors: µ=1.0; aluminium/steel conductors with one layer aluminium: µ~5..10; aluminium/steel conductors with cross section ratio greater equal 6: µ~1.0; steel conductors: µ=25.0 .
Twisted
Indicates, if the phase conductors of the overhead line are twisted or not. The symmetrical ß-twisting will be assumed (cyclical transposition of the phase conductors at 1/3 and 2/3 of the line). The input is valid for each line (phase system).
Earth conductors (Cond. 1 – Cond. 3) X
x-coordinate in m or feet of the earth conductor related to the pylon.
Y
y-coordinate in m or feet of the earth conductor from earth.
Earth cond. 1…3
checkbox: Defines, whether an earth conductor exists or not.
Phase conductors (System 1 – System 6) x (L1)
x-coordinate in m or feet of phase conductor L1 related to the pylon.
y (L1)
y-coordinate in m or feet of phase conductor L1 from earth.
x (L2)
x-coordinate in m or feet of phase conductor L2 related to the pylon.
y (L2)
y-coordinate in m or feet of phase conductor L2 from earth.
x (L3)
x-coordinate in m or feet of phase conductor L3 related to the pylon.
y (L3)
y-coordinate in m or feet of phase conductor L3 from earth.
If a phase does not exist its input data remains zero.
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Coupling-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Coupling-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Coupling-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Description of the Model (Line Coupling) The line couplings are only considered in the short circuit calculation (IEC and superposition method), in the module Distance Protection and for asymmetrical load flow. The formula to calculate the per unit values are: Rc(1) = Rc(1) · lc / Zn Xc(1) = Xc(1) · lc / Zn Yc(1) = Yc(1) · lc · Zn
rc(0) = Rc(0) · lc / Zn xc(0) = Xc(0) · lc / Zn yc(0) = Yc(0) · lc · Zn
The nominal system impedance Zn is calculated as follows. • Coupling between systems with the same nominal system voltage Un Zn = Sn / Un². • Coupling between systems with unequal nominal system voltage Un1, Un2 Zn = Sn / (Un1 · Un2). Sn: base power 100 MVA (set by the program).
Asymmetrical line coupling A line coupling is asymmetrical when at least one line has asymmetrical structure. The matrix for two coupled lines are:
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Element Data Input and Models
U 1L1 U 1 L2 U 1L3 [ Z11 ] = U 2 L1 [ Zc12 ] U 2 L 2 U 2 L3
I1L1 I1 L2 [ Zc12 ] • I1L3 [ Z 22 ] I 2 L1 I 2 L2 I 2 L3
The matrices Z11 and Z22 are current circuit data or series impedance data. The elements of these matrices can be entered in the dialog box for lines. The matrix Zc12 is the coupling matrix between the two 3-phase lines (systems). The elements of this matrix can be entered in the dialog box for line couplings (see above). U 1L1 Zc L1− L1 U 1 = Zc L 2 L1− L 2 U 1L 3 Zc L1− L 3
Zc L1− L 2 Zc L 2− L 2 Zc L 2− L 3
Zc L1− L3 I 2 L1 Zc L 2− L3 • I 2 L 2 Zc L3− L3 I 2 L3
The coupling impedance and admittance matrices can be calculated from the conductor arrangement. The coupling matrix can be transformed into the symmetrical component system with the help of the transformation matrix. It is possible to couple at maximum six 3-phase lines (systems). Each line (system) can have asymmetrical structure, that means any phase(s) can be omitted.
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Pylon The pylon symbol may be placed somewhere near the corresponding lines. In the data input dialog of a pylon, no parameter data may be entered. In the lines and earth conductors the pylons have to be selected and the arrangement data can be entered and modified in the Pylons tab of the line data input dialog, see “Line-Pylons” in chapter “Line” on page 4-13.
Pylon-Parameters Name
Name of element
Earth Conductors
The earth conductors assigned to this pylon are shown with its arrangement data.
Lines
The lines assigned to this pylon are shown with its arrangement data.
Draw
A drawing shows the pylon with the arrangement of the assigned lines and earth conductors.
Pylon-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Pylon-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Pylon-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
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Element Data Input and Models
Coupler This chapter describes the parameters of the Data Input Dialog of a Coupler. Coupler-Parameters Name
Name of element.
Type
Applicable only with a line library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Ir
L
Rated current in kA.
Ipmax
S
Max. allowable peak short circuit current in kA.
Remote controlled
R
Indicates, if the switch is remote controlled.
Bay R configuration
Configuration of the coupler: DCD: Disconnecter – Circuitbreaker - Disconnecter D: Disconnecter
r(1)
D
Positive sequence resistance in per unit.
x(1)
D
Positive sequence reactance in per unit.
r(0)
D
Zero sequence resistance in per unit.
x(0)
D
Zero sequence reactance in per unit.
Remark: The resistance and reactance for the switch model are only necessary to be introduced, when the switches are not reduced during calculation (see "Reduce" option in calculation parameters of the different calculation modules). For load flow calculations with the method "Extended Newton Rapson" these impedances are never relevant, because this LF-method is modeling the switches without impedances. For Dynamic Analysis the impedance data always have to be entered.
Coupler – Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
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Coupler-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Coupler-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
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Element Data Input and Models
Reactor This chapter describes the parameters of the Data Input Dialog of a reactor and the corresponding reactor model. Reactor-Parameters Name
Name of element.
Type
Applicable only with a reactor library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Ur
()
Rated voltage in kV.
Ir
()
Rated current in A.
uRr(1)
()
Copper losses in % of Sr=√3·Ur·Ir.
ukr(1)
()
Short circuit voltage in % of Sr=√3·Ur·Ir.
Reactor-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Reactor-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Reactor-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Reactor-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The
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description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (Reactor) R
X
Fig. 4.5 Model for a reactor
The model parameters of the positive and zero sequence are calculated as follows: Positive and Zero Sequence Z = ukr(1)·Ur/(√3·Ir·100) R = uRr(1)·Ur/(√3·Ir·100) X = √(Z² - R²)
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Element Data Input and Models
Transformer This chapter describes the parameters of the Data Input Dialog of a transformer and the corresponding transformer model. Transformer-Parameters Name
Name of element.
Type
Applicable only with a transformer library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Un1
()
Nominal voltage of the primary winding node (just for information).
Un2
()
Nominal voltage of the secondary winding node (just for information).
Ur1, Ur2
()
Rated voltage of the primary and secondary winding, based on the transformation ratio.
Sr
()
Rated power in MVA.
URr(1)
()
Rated positive sequence copper losses of winding 1 and 2 in % with respect to Sr and Ur1 at tap = tap r.
Ukr(1)
()
Rated positive sequence short circuit voltage in % with respect to Sr and Ur1 at tap = tap r.
URr(0)
SP
Rated zero sequence copper losses for winding 1 and 2 in % with respect to Sr and Ur1 at tap = tap r.
Ukr(0)
SP
Rated zero sequence short circuit voltage in % with respect to Sr and Ur1 at tap = tap r.
U01(0)
SP
Rated zero sequence open circuit voltage in % with respect to Sr and Ur1 at tap = tap r and primary side (feeding from primary side).
U02(0)
SP
Rated zero sequence open circuit voltage in % with respect to Sr and Ur1 at tap = tap r and secondary side (feeding from secondary side).
I0
LMDR
Open circuit current in % with respect to Sr and Ur1.
P fe
LMDR
Iron core losses in kW.
On-load tapchanger
LMDR
If checked, the on-load tapchanging transformers will be regulated automatically during load flow calculation. This parameter is also considered for the impedance correction in the short circuit calculation according to IEC60909.
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Unit transformer
SP
Indicates whether the transformer is part of a power station unit.
Compens. Winding
SP
Indicates, whether the two-winding transformer has a compensation winding. If there is one, the YY-transformer will be modeled according to Fig. 4.8.
Switchable
L
Indicates whether the optimal separation point procedure is allowed to connect or disconnect this element.
Vector Group
SP
Wiring of the windings in nodes 1 and 2. Default value is YD.05. The common vector groups can be selected from a list. The vector groups can be entered according to: • NEPLAN-Format: After the winding designations a point and then voltage phase shifting. E.g. YY.00, YD.05, YZ.5 • DVG-Format: If the neutral is brought out, a ‘N’ or ‘n’ must be set after the corresponding winding designation. E.g. YNYn, YND5, YNZn5
pTap
LMDR
Deviation in % of transformer ratio from nominal Tap. Only necessary for Short Circuit calculations by IEC60909 (2001) and for transformers without on-load tap-changer, which make part of a power station unit.
Operating values before SC Operat. SP values active
For Short Circuit calculation with the norm IEC60909 (2001) an impedance correction factor is introduced in the calculation equations. Check this box, if longterm operating conditions before the short circuit are known, and the correction factor shall be calculated by using the following parameters.
Secondary values Ub max
SP
Highest operating voltage in kV, before short circuit.
Ib max
SP
Highest operating current in A, before short circuit.
Cos(phi)
SP
Angle of power factor, before short circuit.
SP
Lowest operating voltage in kV, before short circuit.
Primary value Ub min
Transformer-Limits Name NEPLAN User's Guide V5
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Element Data Input and Models
Evaluation according to Ir or Sr
LM
The user can select the criteria for the calculation of the transformer loading. If Ir is activated the current (Ir min or Ir max) is taken, if Sr is activated the power (Sr min or Sr max) is taken as reference.
Ir1 min
LM
Minimal current in A for the calculation of the transformer loading on the primary winding. The loading can be calculated according to Ir min or Ir max (see load flow calculation parameters).
Ir1 max
LM
Maximal current in A for the calculation of the transformer loading on the primary winding. The loading can be calculated according to Ir min or Ir max (see load flow calculation parameters).
Ir2 min
LM
Minimal current in A for the calculation of the transformer loading on the secondary winding. The loading can be calculated according to Ir min or Ir max (see load flow calculation parameters).
Ir2 max
LM
Maximal current in A for the calculation of the transformer loading on the secondary winding. The loading can be calculated according to Ir min or Ir max (see load flow calculation parameters).
Sr min
LM
Minimal power in MVA for the calculation of the transformer loading. The loading can be calculated according to Sr min or Sr max (see load flow calculation parameters).
Sr max
LM
Maximum power in MVA for the calculation of the transformer loading. The loading can be calculated according to Sr min or Sr max (see load flow calculation parameters).
Transformer-Regulation Name
Name of element.
Tap side
LMDR
Indicates if the tap location of the tap changer is on the primary or secondary side.
Controlled node
LMDR
Tap min
LMDR
Indicates if the voltage is controlled at the primary or at the secondary node of the transformer or if there is a remote control. With the remote control option, a neighboring node can be controlled with the transformer. The controlled node can be selected from a list (press "…"). Minimum tap settings of the regulated transformer.
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Tap r
LMDR
Rated tap setting.
Tap max
LMDR
Maximum tap settings of the regulated transformer.
Tap act
LMDR
Actual tap setting. This value is used to calculate the ratio of the transformer. Tap act = Tap r has to be set, if the ratio is equal t = Ur1/Ur2.
Ukr(1),Ukr(0) () Tap min
Positive and zero sequence short circuit voltage in % with respect to Sr and Ur1 at tap = tap min.
Ukr(1),Ukr(0) () Tap r
Rated positive and zero sequence short circuit voltage in % with respect to Sr and Ur1 at tap = tap r.
Ukr(1),Ukr(0) () Tap max
Positive and zero sequence short circuit voltage in % with respect to Sr and Ur1 at tap = tap max.
Ukr(1),Ukr(0) () Tap act
Calculated positive and zero sequence short circuit voltage in % with respect to Sr and Ur1 at tap = tap act. These values are calculated with a quadratic interpolation between Ukr of tap min and tap max. During a load flow calculation the short circuit voltage will be adapted according to the tap of the automatically tap changer.
Delta U
LMDR
Magnitude of the additional voltage per tap step on the tap location side. This value must be given in % of the rated voltage on the tap location side of the transformer. A negative value can be entered. In this case the taps are mirrored (see below).
U set
LMDR
Setting voltage in % of nominal voltage of the controlled node. This value can also be entered in the node mask (see "Node Data Input"). This value will be a function of the load current, if compounding is active. The value must be between Umin and Umax (see below). The transformer will regulate to this voltage if the "Auto regulated" option (Params tab) is checked.
Beta
LMDR
Angle in ° of the additional voltage on the tap location side.
P set
LMDR
Regulated power flow of primary winding in % with respect to Sr. For negative power flow insert negative value. This value is only valid for phase shifting transformers (Angle Beta > 0.0).
Compounding Active
LMDR
NEPLAN User's Guide V5
Indicates, if compounding is active or not (see below). If the compounding is not active, the set value will be kept constant at Uset.
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Imin
LMDR
Minimal load current in % of the rated transformer current at the controlled side.
Imax
LMDR
Maximum load current in % of the rated transformer current at controlled side.
Umin
LMDR
Minimal voltage of the controlled node in %. The value Unom must be between Umin and Umax (see above).
Umax
LMDR
Maximum voltage of the controlled node in %. The value Unom must be between Umin and Umax (see above).
Transformer-Earthing Name
Name of element.
Primary side SP
The user can choose between three types of earthing for the primary side: direct, impedance, isolated.
Re1, Xe1
SP
Real- and imaginary part of earthing impedance of side 1 in Ohm. (only for impedance earthing)
Secondary side
SP
The user can choose between three types of earthing for the secondary side: direct, impedance, isolated.
Re2, Xe2
SP
Real- and imaginary part of earthing impedance of side 2 in Ohm. (only for impedance earthing)
Active
SP
For the primary and the secondary side, the user can define, which portion in % of the earthing impedance is active.
Transformer-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Transformer-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
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Transformer-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Transformer-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Regulation: Tap settings The following table shows different possibilities to enter Delta U and to define the Tap changer side. Delta U positive Constant voltage at primary side
Tap changer at primary side
Tap changer at secondary side
Tap act = Tap min
highest secondary voltage
lowest secondary voltage
Tap act = Tap max
lowest secondary voltage
highest secondary voltage
Delta U negative Constant voltage at primary side
Tap changer at primary side
Tap changer at secondary side
Tap act = Tap min
lowest secondary voltage
highest secondary voltage
Tap act = Tap max
highest secondary voltage
lowest secondary voltage
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Compounding If compounding and automatic voltage regulation is active, the set value for the voltage of the controlled node will be changed in function of the transformer load current and according to the characteristic below: Uset
Umax Itr Imin
Imax
Umin
Fig. 4.6 Compounding Characteristic Uset means the set value for the regulated node voltage. Itr is the current, which flows through the transformer during the calculation. If Itr is zero, the set value for the regulated node voltage is the same as the entered value. Possible values are: Umin = 95%, Umax = 105%, Imin=Imax=80%. Recommended Values for Transformer Zero Sequence Reactances: The ratio between the reactances of the positive and zero sequence are dependent on the core structure and of the vector group of the transformer: Vector group Yz with earthing at z -winding
for all transformer types:
Vector group Dy- or Yd with 3-salient pole core: earthing at y-winding 5-salient pole core: 3 one pole transformers:
X(0)/X(1) = 0.1 .. 0.15 X(0)/X(1) = 0.7 .. 1.0 (Sr small: X(0)/X(1) = 1.0) X(0)/X(1) = 1.0 X(0)/X(1) = 1.0
Vector group Yy with compensation winding and earthing at y-winding
for all transformer types:
X(0)/X(1) = 1.0 .. 2.4 1)
Vector group Yy- or Yz without compensation
3-salient pole core:
X(0)/X(1) = 3.0 .. 10.0 1)
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winding and earthing at ywinding:
5-salient pole core: 3 one pole transformers:
X(0)/X(1) = 10.0 .. 100.0 1) X(0)/X(1) = 10.0 .. 100.0 1)
1)
Very dependent on the transformer's structure and the ratio between the leakage flux to useful flux (the leakage flux goes partly through the transformer tank).
Remark:
Regulated transformers are only regulated automatically during load flow calculation, when the "Auto regulated" option in the Params tab is checked. Description of the Model (Transformer) The models for load flow, short circuit and harmonic analysis calculations are different. The following figure shows the model of a transformer for load flow calculation. R
Y/2
X
Y/2
t:1 Fig. 4.7 Model of a transformer for load flow calculation
The model parameters of the positive sequence are calculated as follows: Positive sequence Z = Ukr(1)·Ur1²/(Sr·100) X = √(Z²-R²) Y0 = I0·Sr/(100·Ur1²)
NEPLAN User's Guide V5
R = URr(1)·Ur1²/(Sr·100) YFe = PFe/Ur1² Y = YFe - j·√(Y0²-YFe²)
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Calculation of Regulated Transformer The voltage and ratio are calculated as follows: Tap max Tap act ß Tap mit U Tap min
Ur reg
Ur
Fig. 4.8 Regulated Transformer
Regulation on Primary Side Ur1reg = Ur1 + (Tapact - Tapr) ·Ur1·∆U/100·[cos(ß)+j·sin(ß)] treg = Ur1reg/Ur2 Regulation on Secondary Side Ur2reg = Ur2 + (Tapact - Tapr) ·Ur2·∆U/100·[cos(ß)+j·sin(ß)] treg = Ur1/Ur2reg If ß = 0 the voltage can be controlled. If ß = 90 the active power can be controlled. If 0 < ß < 90 the power or the voltage can be controlled. Transformer Model for Short Circuit Calculation The following figure shows the transformer model for a short circuit calculation of positive sequence. R
X
t:1
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Fig. 4.9 Transformer model for short circuit calculation of positive sequence
The transformer model of the zero sequence is dependent on the vector group (see Fig. 4.8 - 4.10). 3 · Ze1
Z
3 · Ze2
t:1
If Ze1 < 100.0 and Ze2 >>: 3 · Ze1
Z
If U01(0) ≠ 0.0 and U02(0) ≠ 0.0: 3 · Ze1
Z1
Z2
3 · Ze2
Zh
t:1
Fig. 4.10 Transformer model for short circuit calculation (vector group YY) of zero sequence
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3 · Ze1
Z
Fig. 4.11 Transformer model for short circuit calculation (vector group YD or ZY) of zero sequence
Fig. 4.12 Transformer model for short circuit calculation (vector group DD) of zero sequence
The model parameters of the positive and zero sequence are calculated as follows: Positive sequence
Zero sequence
Z = Ukr(1)·Ur1²/(Sr·100) R = URr(1)·Ur1²/(Sr·100) X = √(Z²-R²) Z = R + j·X Ze1 = Re1 + j·Xe1
Z = Ukr(0)·Ur1²/(Sr·100) R = URr(0)·Ur1²/(Sr·100) X = √(Z²-R²) Z = R + j·X Ze2 = Re2 + j·Xe2 Z10 = U01(0)·Ur1²/(Sr·100) X10 = √(Z10²-R²) Z10 = R + j·X10 Z20 = U02(0)·Ur1²/(Sr·100) X20 = √(Z20²-R²) Z20 = R + j·X20
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The impedances Z1, Z2 and Zh in Fig. 4.8 can be calculated from the following equations (Ze1=Ze2=0.0): Z10 = Z1 + Zh Z20 = Z2 + Zh Z = Z1 + Z1·Z2 / (Z1+Z2) ≈ Z1 + Z2 Z10, Z20 and Z are input values and given above.
Note:
For Short circuit calculations according to IEC the impedance Z will be multiplied by a correction K: IEC909 (1988) Unit transformer: Network transformer:
K = cmax K = 1.0
/2/
IEC60909 Unit transformer with on-load tapchanger: K=
Un
2
U rG
2
⋅
U rTLV
2
U rTHV
2
⋅
c max 1 + xd " − xT ⋅ sin ϕ rG
Unit transformer without on-load tapchanger: K=
U rG
Un U c max ⋅ rTLV ⋅ (1 ± pT ) ⋅ ⋅ (1 + pG ) U rTHV 1 + xd " ⋅ sin ϕ rG
Network transformer: K = 0.95 ⋅
with Un Ub Ib phib Ir xT cmax UrTLV
c max 1 + 0.6 ⋅ xT
or
K=
Un c max ⋅ U b 1 + xT ⋅ I b ⋅ sin ϕ I b r
Nominal system voltage of connecting node Highest operating voltage before SC Highest operating current before SC Angle of power factor before SC Rated current of transformer Transformer reactance maximum voltage factor Transformer rated voltage on low-voltage side
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UrTHV UrG pG (1+pT)
4-50
Transformer rated voltage on high-voltage side Rated voltage of unit generator Deviation of generator terminal voltage from rated voltage Used off-load tap
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Asymmetrical Transformer This chapter describes the parameters of the Data Input Dialog of an asymmetrical transformer and the corresponding transformer model. Asym. Transformer-Parameters Name
Name of element.
Type
Applicable only with an asymmetrical transformer library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Switchable
L
Indicates whether the optimal separation point procedure is allowed to connect or disconnect this element.
Negative polarity
LMDR
Mark this checkbox, if you wish the transformer to have negative polarity, like shown below. L
L
N
N
L
L
N
N
positive polarity
negative polarity
Un1
()
Nominal voltage of the primary winding node (just for information).
Un2
()
Nominal voltage of the secondary winding node (just for information).
Ur1, Ur2
()
Rated voltage of the primary and secondary winding, based on the transformation ratio. When the phase configuration is Phase to Neutral (L1N, L2N or L3N), then the value for the rated voltage Ur has to be given as a phase to earth value.
Sr
()
Rated power in MVA.
URr(1)
()
Rated positive sequence copper losses of winding 1 and 2 in % with respect to Sr and Ur1 at tap = tap r.
Ukr(1)
()
Rated positive sequence short circuit voltage in % with respect to Sr and Ur1 at tap = tap r.
I0
LMDR
Open circuit current in % with respect to Sr and Ur1.
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P fe
LMDR
Iron core losses in kW.
Phases
()
Indicates the phases of the transformer on primary and secondary side. If the input of the phases and the input of the vector group don't match together, the phase indication will be decisive. When the phase configuration is Phase to Neutral (L1N, L2N or L3N), then the value for the rated voltage Ur has to be given as a phase to earth value.
Vector Group
()
The following vector groups may be chosen: 1.) E – E 2.) E – 2E 3.) 2E – E The transformer side with E has a Phase-Phase or Phase-Neutral connection. The transformer side with 2E has a Phase-NeutralPhase connection. See the model of the asymmetrical transformer.
Regulation Tap min
LMDR
Minimum tap settings of the regulated transformer.
Tap r
LMDR
Rated tap setting.
Tap max
LMDR
Maximum tap settings of the regulated transformer.
Tap act
LMDR
Actual tap setting. This value is used to calculate the ratio of the transformer. Tap act = Tap r has to be set, if the ratio is equal t = Ur1/Ur2.
Delta U
LMDR
Magnitude of the additional voltage per tap step on the tap location side. This value must be given in % of the rated voltage on the tap location side of the transformer. A negative value can be entered. In this case the taps are mirrored (see below).
Tap side
LMDR
Indicates, if the tap location of the tap changer is on the primary or secondary side.
Controlled bus
LMDR
Indicates, if the voltage is controlled on primary or on secondary side of the transformer.
U set
LMDR
Setting voltage in % of nominal voltage of the controlled node. This value can also be entered in the node mask (see "Node Data Input"). The transformer will regulate to this voltage if the "Auto regulated" option is checked.
Auto
LMDR
Indicates whether the transformer should be regulated
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regulated
automatically for the load flow calculation.
Asym. Transformer-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Asym. Transformer-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Asym. Transformer-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Asym. Transformer-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6
Description of the Model (Asymmetrical Transformer) Depending of the vector group of the asymmetrical transformer, E/E or 2E/E, the following models are valid:
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Element Data Input and Models
X
Yh/2
Yh/2
t:1 a) Model E/E X
1 : 2a
U 1R Yh/4
Yh/4
Yh/4
Yh/4
U 2R
U 1N
U 1S X
U 2S
1 : 2a
b) Model 2E/E
Fig. 4.13 Model of the asymmetrical transformer
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Three Windings Transformer This chapter describes the parameters of the Data Input Dialog of a three windings transformer and the corresponding transformer model.
3W-Transformer-Parameters Name
Name of element.
Type
Applicable only with a 3W-Transformer library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Un1
()
Nominal voltage of the primary winding node (just for information).
Un2
()
Nominal voltage of the secondary winding node (just for information).
Un3
()
Nominal voltage of the tertiary winding node (just for information).
Ur1, Ur2, Ur3
()
Rated voltage of the primary, secondary and tertiary winding, based on the transformation ratio.
Sr12, Sr23, Sr31 ()
Rated power in MVA. 12: primary-secondary, 23: secondary-tertiary, 31: tertiary-primary.
URr(1)12, 23, 31 ()
Rated positive sequence copper losses in % with respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3.
Ukr(1)12, 23, 31 ()
Rated positive sequence short circuit voltage with respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3.
Ukr(0) 12,23,31
SP
Rated zero sequence short circuit voltage with respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3.
I0
LMDR
Open circuit current in % with respect to Sr12 and Ur1. This value is only considered in the Loadflow calculation, method Extended Newton Raphson.
P fe
LMDR
Iron core losses in kW. This value is only considered in the Loadflow calculation, method Extended Newton Raphson.
Auto regulated
LMDR
Indicates if the transformer in the load flow calculation should be automatically regulated. The
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following is assumed, when calculating the Loadflow with Newton Raphson or Current Iteration method: If the box is checked, the program assumes a two-windings transformer with a compensation winding. In this case the model of a twowinding transformer is taken (see "Transformer" on page 4-38). The tertiary node will be neglected. No load can be connected to the tertiary node. Compens. Winding
SP
Indicates, whether the three-winding transformer has a compensation winding. If there is one, the YYY-transformer will be accurately modeled in the zero system.
Vector group
SP
Winding connection in nodes 1, 2 and 3. The winding coefficient has to be given, with respect to node 1 according to VDE 0532/1. The common vector groups can be selected from a list. The vector groups can be entered according to: • NEPLAN-Format: After the winding designations a point and then voltage phase shiftings, which are also separated with a point. The coefficient of the winding in node 1 must be set to zero or it can be neglected (e.g. YYD.0.5 instead of YYD.0.0.5). • DVG-Format: If the neutrals are brought out, a ‘N’ or ‘n’ must be set after the corresponding winding designation. E.g. YNYn0d5
3W-Transformer-Limits Name
Name of element.
Ir 1,2,3 min
LM
Minimal current on primary, secondary and tertiary side in A for the calculation of the transformer loading. The loading can be calculated according to Sr min or Sr max resp. Ir min or Ir max (see load flow calculation parameters).
Ir 1,2,3 max
LM
Maximum current on primary, secondary and tertiary side in A for the calculation of the transformer loading. The loading can be calculated according to Sr min or Sr max resp. Ir min or Ir max
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(see load flow calculation parameters). Sr min
LM
Minimal power in MVA for the calculation of the transformer loading. The loading can be calculated according to Sr min or Sr max resp. Ir min or Ir max (see load flow calculation parameters).
Sr max
LM
Maximum power in MVA for the calculation of the transformer loading. The loading can be calculated according to Sr min or Sr max resp. Ir min or Ir max (see load flow calculation parameters).
Evaluation acc. to Sr or Ir
LM
The user can select the criteria for the calculation of the transformer loading. If Ir is activated the currents (Ir 1,2,3 min or Ir 1,2,3 max) are taken, if Sr is activated the power (Sr min or Sr max) is taken.
3W-Transformer-Regulation 1st Regulation Tap side
LMDR
Indicates if the tap location of the tap changer is on the primary, secondary or tertiary side.
Controlled node
LMDR
The node to be controlled must be selected from a list, press "…". If there is no node selected, the tap location node will be controlled. Remote control: A neighboring node can also be controlled with the transformer. The controlled node can be selected from a list (press "…"). Remote control is only possible if the input field "Transf.regul." is set to YES.
Tap min
LMDR
Minimum tap settings of the regulated transformer.
Tap max
LMDR
Maximum tap settings of the regulated transformer.
Tap r
LMDR
Rated tap setting.
Tap act
LMDR
Actual tap setting. This value is used to calculate the ratio of the transformer. For the tap calculation see "Transformer" on page 4-38.
Ukr(1) 12,23,31 Ukr(0) 12,23,31 Tap min
()
Positive and zero sequence short circuit voltage in % with respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3 at tap = tap min.
Ukr(1) 12,23,31
()
Rated positive and zero sequence short circuit
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voltage in % with respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3 at tap = tap r.
Ukr(0) 12,23,31 Tap r Ukr(1) 12,23,31 Ukr(0) 12,23,31 Tap max
()
Positive and zero sequence short circuit voltage in % with respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3 at tap = tap max.
Ukr(1) 12,23,31 Ukr(0) 12,23,31 Tap act
()
Positive and zero sequence short circuit voltage in % with respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3 at tap = tap act. These values are calculated with a quadratic interpolation between ukr of tap min and tap max.
dU
LMDR
Magnitude of the additional voltage per tap step on the tap location side. This value must be given in % of the rated voltage on the tap location side of the transformer. A negative value can be entered. In this case the taps are mirrored (see "Transformer" on page 4-38).
Beta
LMDR
Angle in ° of the additional voltage on the tap location side.
P set
LMDR
Regulated power flow of primary winding in % with respect to Sr12. For negative power flow insert negative value. This value is only valid for phase shifting transformers (Angle Beta > 0.0) and if the option "Auto regulated" is checked.
U set
LMDR
Setting voltage in % of nominal voltage of the controlled node. This value can also be entered in the node mask (see "Node Data Input"). This value will be a function of the load current, if compounding is active. The value must be between Umin and Umax (see below). The transformer will regulate to this voltage if the option "Auto regulated" (Params tab) is checked.
Tap side
LMDR
Indicates if the tap location of the tap changer is on the primary, secondary or tertiary side. It can't be the same winding as in the 1st regulation. The taps of the 2nd regulation can only be changed manually (it won't be automatically).
Tap min
LMDR
Minimum tap settings of the 2nd tap changer.
Tap max
LMDR
Maximum tap settings of the 2nd tap changer.
Tap r
LMDR
Rated tap setting.
2nd Regulation
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Tap act
LMDR
Actual tap setting. This value is used to calculate the ratio of the transformer.
dU
LMDR
Magnitude of the additional voltage per tap step on the tap location side. This value must be given in % of the rated voltage on the tap location side of the transformer. A negative value can be entered. In this case the taps are mirrored (see below).
Beta
LMDR
Angle in ° of the additional voltage on the tap location side.
3W-Transformer-Earthing Name
Name of element.
Primary side
()
The user can choose between three types of earthing for the primary side: direct, impedance, isolated.
Re1, Xe1
SP
Real- and imaginary part of earthing impedance of side 1 in Ohm. (only for impedance earthing)
Secondary side
SP
The user can choose between three types of earthing for the secondary side: direct, impedance, isolated.
Re2, Xe2
SP
Real- and imaginary part of earthing impedance of side 2 in Ohm. (only for impedance earthing)
Tertiary side
SP
The user can choose between three types of earthing for the tertiary side: direct, impedance, isolated.
Re3, Xe3
SP
Real- and imaginary part of earthing impedance of side 3 in Ohm. (only for impedance earthing)
Active
SP
It's possible to define, which portion in % of the earthing impedance is active on primary, secondary and tertiary side.
3W-Transformer-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
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3W-Transformer-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
3W-Transformer-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
3W-Transformer-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6
Description of the Model (3-W Transformer) The three windings transformer will be modeled by three two windings transformer (models see "Transformer" on page 4-38). The calculation of the model parameters is: Positive sequenze
Zero sequence
Zij = Ukr(1)ij·Uri²/(Srij·100) Rij = URr(1)ij·Uri²/(Srij·100) Xij = √(Zij²-Rij²) Zij = Rij + j·Xij
Zij = Ukr(0)ij·Uri²/(Srij·100) Rij = 0 Xij = Zij Zij = j·Xij
ij ε {12, 23, 31} i ε {1, 2, 3} 4-60
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Ze1 = Re1 + j·Xe1 Ze3 = Re3 + j·Xe3
1
Z1
Ze2 = Re2 + j·Xe2
Z2
4
2
Z3
3
Z1 = 0.5 * (Z12 + Z13 – Z23) Z2 = 0.5 * (Z23 + Z12 – Z13) Z3 = 0.5 * (Z13 + Z23 – Z12) The ficticious node 4 will be internally reduced, thus a 3 winding transformer will be represented by a 3x3 matrix.
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Four Windings Transformer This chapter describes the parameters of the Data Input Dialog of a 4WTransformer and the corresponding transformer model.
4W-Transformer-Parameters Name
Name of element.
Type
Applicable only with a 4W-Transformer library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Un1, Un2, Un3, Un4
()
Nominal voltage of the primary, secondary, tertiary and 2. tertiary winding node.
Ur1, Ur2, Ur3, Ur4
()
Rated voltage of the primary, secondary, tertiary and 2. tertiary winding, based on the transformation ratio.
Sr1, Sr2, Sr3, Sr4
()
Rated power in MVA of the primary, secondary, tertiary and 2. tertiary winding
URr(1)12, 13, 14, 23, 24, 34
()
Rated positive sequence copper losses in % with respect to Sr4 and Ur1, Ur2, Ur3, Ur4.
Ukr(1)12, 13, 14, () 23, 24, 34
Rated positive sequence short circuit voltage with respect to Sr4 and Ur1, Ur2, Ur3, Ur4.
Ukr(0)12, 13, 14, SP 23, 24, 34
Rated zero sequence short circuit voltage with respect to Sr4 and Ur1, Ur2, Ur3, Ur4.
Vector group
Winding connections in nodes 1, 2, 3 and 4. The winding coefficient has to be given, with respect to node 1 according to VDE 0532/1. The common vector groups can be selected from a list. The vector groups can be entered according to: • NEPLAN-Format: After the winding designations a point and then voltage phase shifting. E.g. YY.00, YD.05, YZ.5 • DVG-Format: If the neutral is brought out, a ‘N’ or ‘n’ must be set after the corresponding winding designation. E.g. YNYn, YND5, YNZn5
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4W-Transformer-Regulation There is no automatic regulation possible for the 4W-Transformer. The tap have to be changed manually. Name
Name of element.
Tap side
LMDR
Indicates if the tap location of the tap changer is on the primary, secondary, tertiary or 2. tertiary side.
Tap min
LMDR
Minimum tap settings of the tap changer.
Tap max
LMDR
Maximum tap settings of the tap changer.
Tap r
LMDR
Rated tap setting.
Tap act
LMDR
Actual tap setting. This value is used to calculate the ratio of the transformer. For the tap calculation see "Transformer" on page 4-38.
dU
LMDR
Magnitude of the additional voltage per tap step on the tap location side. This value must be given in % of the rated voltage on the tap location side of the transformer. A negative value can be entered. In this case the taps are mirrored (see "Transformer" on page 4-38).
4W-Transformer-Earthing Name
Name of element.
Primary side
()
The user can choose between three types of earthing for the primary side: direct, impedance, isolated.
Re1, Xe1
SP
Real- and imaginary part of earthing impedance of side 1 in Ohm. (only for impedance earthing)
Secondary side
()
The user can choose between three types of earthing for the secondary side: direct, impedance, isolated.
Re2, Xe2
SP
Real- and imaginary part of earthing impedance of side 2 in Ohm. (only for impedance earthing)
Tertiary side
()
The user can choose between three types of earthing for the tertiary side: direct, impedance, isolated.
Re3, Xe3
SP
Real- and imaginary part of earthing impedance of side 3 in Ohm. (only for impedance earthing)
2. Tertiary side
()
The user can choose between three types of earthing for the tertiary side: direct, impedance,
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isolated. Re4, Xe4
SP
Real- and imaginary part of earthing impedance of side 4 in Ohm. (only for impedance earthing)
Active
SP
It's possible to define, which portion in % of the earthing impedance is active on primary, secondary and tertiary and 2. tertiary side.
4W-Transformer-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
4W-Transformer-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3
4W-Transformer-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
4W-Transformer-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
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Description of the Model (4W-Transformer) The four windings transformer will be modeled by four two windings transformer (models see "Transformer" on page 4-38). The calculation of the model parameters is: Positive sequence
Zero sequence
Zij = ukr(1)ij·Uri²/(Sr4·100) Rij = uRr(1)ij·Uri²/(Sr4·100) Xijij = √(Zijij²-Rij²) Zij = Rij + j·Xij ZEi = REi + j·Xei
Zij = ukr(0)ij·Uri²/(Sr4·100) Rij = 0 Xij = Zij Zij = j·Xij
i ε {1, 2, 3} ij ε {12, 13, 14, 23, 24, 34} ; e.g. Z24 = ukr(1)24·Ur2²/(Sr4·100)
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Shunt This chapter describes the parameters of the Data Input Dialog of a shunt and the corresponding shunt model. Shunt-Parameter Name
Name of element.
Type
Applicable only with a shunt library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library
Control mode
()
There are three different type of control modes: • fixed: The shunt consists of a fixed value of active and reactive power. • discrete: The shunt consists of various shunt elements, which will be connected or disconnected, depending on the regulated voltage. • continuously: The shunt will be able to change the reactive power continuously, without steps, in the defined range.
Ur
()
Rated voltage in V.
Fixed admittance P(1)
()
Positive sequence active power in MW. Dependent on the phase connectivity (see Info tab) the value must be entered as phase value.
Q(1)
()
Positive sequence reactive power in Mvar. Q(1) is negative for a capacitive load. Dependent on the phase connectivity (see Info tab) the value must be entered as phase value.
P(0)
SP
Zero sequence active power in MW. This value has not to be entered when entering an asymmetrical shunt. It will be calculated.
Q(0)
SP
Zero sequence reactive power in Mvar. Q(0) is negative for a capacitive load. This value has not to be entered when entering an asymmetrical shunt. It will be calculated.
Operating mode
()
Indicates if the shunt is capacitive or inductive, depending on the sign of the entered reactive power Q. (negative value means capacitive mode, positive value means inductive mode)
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Effective Q-scaling factor
()
Depending on the operational mode, the predefined scaling factors for capacitive or inductive Q are taken to calculated the effective scaling factor, which is displayed in this field. The predefined scaling factors for the network and zones may be modified in “Data Operational Data” of the menu Edit (see chapter “Menu Options”). The user can’t define “User Defined Scaling Factors” for the shunts.
Switched admittance blocks Remote controlled
LMDR
Check this option, if an other node than the shunt node has to be controlled. By mouse click on “…” the remote node may be chosen from a list.
U set
LMDR
Setting voltage in % of nominal voltage of the controlled node. This value can also be entered in the node mask (see "Node Data Input").
Switched admittance blocks
LMDR
There may be defined blocks of reactive power, each one of which consists of various steps.
Remarks:
The switched shunt elements at a bus may consist entirely of reactors (all admittance blocks have positive values for dQ) or entirely of capacitor banks (all admittance blocks have negative values for dQ). In these cases, the shunt blocks are specified in the order in which they are switched on the bus. If the switched shunt devices at a bus are a mixture of reactors and capacitors, the reactor blocks are specified first in the order in which they are switched on, followed by the capacitor blocks in the order in which they are switched on. The difference between the continuous and the discrete regulation is only, that for the continuous mode, the reactive power can vary continuously in the whole defined range, without steps.
Shunt-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2. The option Phases has additional possibilities because shunts may be placed as well between phases: Phases
()
NEPLAN User's Guide V5
Indicates the phasing of the element. Possible values are:
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- L1L2L3N: - L1N: - L2N: - L3N: - L1L2: - L1L3: - L2L3:
Symmetrical shunt impedance Single phase shunt impedance, phase L1 Single phase shunt impedance, phase L2 Single phase shunt impedance, phase L3 Impedance between phases L1 and L2 Impedance between phases L1 and L3 Impedance between phases L2 and L3
Shunt-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Shunt-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Shunt-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (Shunt)
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R
X
Fig. 4.14 Model of shunt
The model parameters of the positive and zero sequence are calculated as follows: Positive sequence
Zero sequence
R = P(1)·Ur²/(P(1)²+Q(1)²) X = Q(1)·Ur²/(P(1)²+Q(1)²)
R = P(0)·Ur²/(P(0)²+Q(0)²) X = Q(0)·Ur²/(P(0)²+Q(0)²)
If Q(1) is given as a negative value, in the module Harmonic analysis the following is taken for X: X = -1.0 / X (capacitive).
If an asymmetrical shunt has been entered, the program will transform the parameters from the phase into the symmetrical component system with the transformation matrix.
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Converter This chapter describes the parameters of the Data Input Dialog of a Converter and the corresponding Converter model.
Converter-Parameters Name
()
Type
()
Converter type Rectifier, () Inverter
Name of the converter.
Indicates, if the converter is a - Rectifier - Inverter
Regulation Regulation
()
The converter can be P: Power regulated I: Current regulated A+U: Voltage and angle regulated
Pset
()
Set value for power regulation in MW.
Umode
()
Minimum voltage for power regulation (for voltages below Umode control shifts to constant current with Iset =Pset/Uset)
Iset
()
Set value for current regulation in kA.
Uset
()
Set value for voltage regulation in kV. In case of power regulation Uset denotes the voltage used for calculating the new setvalue at the control mode shift (see Umode).
Teta set
()
Set value for the rectifier firing or inverter margin angle in °. This value is only valid for “A+U” regulated converter
Teta min
()
Minimum value for the rectifier firing or inverter margin angle in °.
Teta max
()
Minimum value for the rectifier firing or inverter margin angle in °.
()
Indicates, if the converter transformer should be included in the converter. If clicked, no external transformer must be defined, the converter represents a converter plus a
Firing angle
Transformer Transformer integrated
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transformer. T
()
Nominal tap ratio of the converter transformer in pu from DC to AC side.
Tap locked
()
If this parameter is checked the tap will be fixed on T.
dT
()
Converter transformer tap-step in pu.
T min
()
Minimum value of converter transformer tap ratio in pu.
T max
()
Maximum value of converter transformer tap ratio in pu.
negative pole
()
The converter is a negative pole
positive pole ()
The converter is a positive pole
numb. bridges
()
Number of three-phase converter bridges in series
Xc
()
Commutating reactance in Ohm.
RLoss
()
Equivalent total active power losses in the valves and auxiliaries in Ohm. This parameter is only considered in Loadflow calculation, method Extended Newton Raphson.
Vdrop
()
Voltage drop across the valves in V. This parameter is only considered in Loadflow calculation, method Extended Newton Raphson.
Im
()
Current margin in % of the current set value Iset.
Im distrib.
()
This is the converter participation factor in % in case of a multi-terminal system. If the current order at any rectifier is reduced, current orders of remaining converters are modified in proportion by these factors.
Grounding node
()
Name of grounding node in case of a bipole HVDC link. One corresponding negative and positive pole of a terminal must have the same grounding node.
Rg
()
Grounding resistance in Ohm.
Converter-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
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Converter-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Converter-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Converter-More… Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (Converter) Every HVDC system consists of rectifiers and inverters, which are called converter. The basic equations for a converter are (rectifier): U d = U d 0 ⋅ cos(α ) −
Ud =
3⋅ 2
π
3
π
⋅ X c ⋅ T ⋅ B ⋅ I d − Rl ⋅ I d − Vdrop
with
Ud0 =
3⋅ 2
π
⋅ B ⋅ T ⋅ E ac
⋅ B ⋅ T ⋅ E ac ⋅ cos(φ )
Qac = Pac ⋅ tan (φ ) Pac = Pd = U d ⋅ I d I ac =
6 ⋅B
π
⋅ Id
The equation for a DC line is: U di = U dr − Rdc ⋅ I d
The abbreviations are: Ud: Converter DC voltage; Udi for inverter, Udr for rectifier Eac: Converter AC voltage Pac: Active power at AC terminal 4-72
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Qac: Iac: Pd: Vdrop: B: T: Xc: Rl : Rdc: Id: ϕ:
Reactive power at AC terminal AC current DC power at DC terminal Voltage drop across the valves Number of bridges Transformer ratio from DC to AC Commutating reactance Losses in the valves Resistance of the DC line Converter DC current AC power factor angle
α:
Firing angle (for rectifier)
An equivalent circuit for a converter can be drawn as follows: α E ac P ac , Q ac
Ud
1:T
Xc
I dc
Fig. 4.15 Equivalent circuit of a converter
The DC voltage Ud and/or the DC current Id are controlled by the firing angle alpha and the converter transformer ratio T. The firing angle and the transformer ratio (tap position) are varied within their limits.
HVDC Systems in NEPLAN NEPLAN can handle any number of two-terminal and multi-terminal HVDC systems. The following configurations are possible:
Fig. 4.16 Monopolar HVDC link NEPLAN User's Guide V5
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+
Fig. 4.17 Bipolar HVDC link
G
G
Fig. 4.18 Meshed multi-terminal HVDC system
In a two-terminal system, there are a rectifier and an inverter, one of them controls the DC voltage (normally the inverter) and one the DC current or DC power. In a multi-terminal system there is at least one converter, which controls the DC voltage. The normal operation of a two-terminal system can be described by the following diagram:
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Udi Rectifier, current controlled Inverter, voltage controlled
Udset Operating point
Im
Idi
Idrset
Fig. 4.19 Normal operation of a two-terminal system
In the normal mode of operation the margin angle of the inverter is adjusted to maintain the desired inverter DC voltage Udset. The ratios of the inverter and rectifier transformer are also adjusted, so that the firing angle alpha and the margin angle gamma are within their limits min and max. In the current controlling rectifier a voltage margin of about 3% is maintained in order to avoid frequent changes in control allocations. For that reason if the minimum firing angle for the rectifier is 5-7° the operating firing angle will typically have values 14° ≤ α ≤ 16° . If the rectifier AC voltage is too low and the transformer ratio has reached the limit, the voltage control of the inverter will be abandoned. The inverter now will control the current: The current order Idiset at the inverter is lower than the current order Idrset (the current margin is defined as Im = Idrset - Idiset). The new operating point can be described as follows:
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Udi
Inverter, current controlled
Udset Operating point
Im
Idiset
Idrset
Fig. 4.20 Current control of the inverter
Analogous can be said for multi-terminal systems. The configuration considered is this of the parallel arrangement: The current in all the converter stations (of number n) except one are adjusted according to current or power control setpoints. One converter per pole (usually the one with the lower voltage ceiling) will control the voltage. Current control is also provided at the voltage setting terminal, so that it satisfies the following equation:
∑ Iset
j =1..n
j
= I m arg in
j j where Imargin is a positive quantity, and Iset > 0 if j is a rectifier, Iset < 0 if j is an inverter.
In case of voltage depression in a current controlled converter, voltage control will be shifted to this converter and the current settings of the remaining j terminals will be changed according to the participation factors Im distrib . If i denotes the converter that hits the minimum angle limit, the new current setpoint of any converter j ≠ i can be calculated using:
mi ⋅ Iset i Iset new = Iset + isrec ⋅ a , t a ∑
(
j
)
j
j
t ≠i
where isrec = 1 if j is a rectifier and isrec = −1 if j is an inverter.
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j
The coefficient a is calculated using the following formula
Im distrib j / 100. nInv ⋅ a = , if j Rectifier SCoeff nInv + nRec Im distrib j / 100. nRec j ⋅ a = , if j Inverter SCoeff nInv + nRec j
where
SCoeff = ∑ Im distib i / 100. i∈C
and C all converters apart from the voltage controlling terminal that are not blocked.
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SVC (Controlled static VAR Compensator) This chapter describes the parameters of the Data Input Dialog of a SVC and the corresponding SVC model. The configuration assumed is that of a fixed capacitor and a thyristor controlled reactor. SVC-Parameters Name
Name of element.
Transformer
LMDR
Indicates if there is a transformer in the static VAR system.
U ref
LMDR
Reference voltage for the regulation.
X sl
LMDR
Slope admittance: slope of the linear mode in the U/I characteristic curve (see below).
Qc max
LMDR
Maximal capacitive reactive power in Mvar. Qcmax is a positive value and means the maximum generated inductive reactive power of the SVC at nominal voltage. Qcmax corresponds to the reactive power of the fix capacitor.
Ql max
LMDR
Maximal inductive reactive power in Mvar. Qlmax is a positive value and means the maximum consumed inductive reactive power of the SVC at nominal voltage. Qlmax corresponds to the maximum reactive power of the inductance Ql minus the maximum reactive power Qc max of the capacitor: Qlmax = Ql – Qcmax (see Fig. 4.13)
SVC-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
SVC-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
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SVC-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
SVC-More… Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (Static VAR Compensator) For load flow calculations a regulated VAR compensator can be described as follows: HV
U2
VT
Transformer I2 U1
LV
Controller Ql
F
L
C 0 Qc max
SVC
Fig. 4.21 Model of a SVC
F: Filter C: fix capacitor L: thyristor controlled reactor The elements filter, controlled reactor and capacitor will be modeled with the shunt element. The characteristic of a SVC is:
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U2 Ql max Umax
Uref
∆I
Umin
∆U
∆U/∆I=Xsl
Qc max capacitive
inductive I2
Imin
Imax
Fig. 4.22 SVC characteristic curve
There are three modes: capacitive mode (U2 = Umax): I2 = Bind * U1 with Bind = Bl0 - Bc0 and Bl0 = (Qcmax + Qlmax) / U2n2 ; Qcmax, Qlmax : input values linear control range, normal mode ( Umin = Umax): I2 = (U2 - Uref)/Xsl for Xsl ≠ 0 ; Xsl : input value U2 = Uref for Xsl = 0 The equivalent circuits are:
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U1
XSL
U2
U1
I2
Bcap
Uref
Linear mode
XT
U2
U1
I2
Capacitive mode
XT
Bind
U2 I2
Inductive mode
Fig. 4.23 Equivalent circuits of a SVC
XT: Reactance of the transformer The data of the transformer are entered separately. In the SVC, the user has to indicate only if there is a transformer or not by clicking the corresponding checkbox in the Data Input Dialog of the SVC. If there is no transformer, the regulated/controlled VAR compensator works like a PV-node with P=0.0 MW and U = Unom. This behaviour is similar to that of synchronous machines. The reactive power will be calculated. If the limits Qcmax .. Qlmax are reached, the regulated VAR compensator will be converted into a constant inductance or capacitance (see the figure above) and not into a PQ-node with Q = Qcmax or Q = Qlmax, like in the case of a synchronous machine. The input of Qcmax, Qlmax and the slope Xsl determine the characteristic of the SVC. If Qlmin = 1) identical TCSC modules connected in series and controlled independently. TCSC-Parameters Name Operation
Name of element. LMDR
Indicates if there is one single TCSC module or several modules in series.
Module Parameters Xc
LMDR
Reactance of the capacitor in Ohm
Xl
LMDR
Reactance of the inductor in Ohm
X Limits, Teta Limits
LMDR
Limits on total reactance of the TCSC or on Thyristor firing angle. In case of multi-module operation, only X Limits can be entered.
X min
LMDR
Minimum value of module reactance (negative for capacitive operation). The (X min,X max) range should not contain any resonance region.
X max
LMDR
Maximum value of module reactance (negative for capacitive operation). The (X min,X max) range should not contain resonance values.
Teta min
LMDR
Minimum value of thyristor firing angle. The (Teta min, Teta max) range should not contain resonance values.
Teta max
LMDR
Maximum value of thyristor firing angle. The (Teta min, Teta max) range should not contain resonance values.
Max. Volt. Drop
LMDR
Maximum allowed voltage drop in kV.
LMDR
Selection of the variable to be controlled. P: Line power flow I: Line current Xtot: Total TCSC reactance in Ohm Transm. Angle: Transmission angle
Regulation P, I, Xtot, Transm. angle
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Pset
LMDR
Control value for line active power flow control in MW.
Iset
LMDR
Control value for line current control in A.
Xtot
LMDR
Control value for total TCSC reactance control in Ohm.
Transm. angle
LMDR
Control value for transmission angle (angle U1 – angle U2) control in °.
TCSC-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
TCSC-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
TCSC-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
TCSC-More… Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (TCSC) The TCSC consists of a fixed capacitor connected in parallel with a thyristor controlled reactor (TCR) (see figure below). The TCR is the main control unit of the TCSC: By means of the firing angle of the thyristors, the effective inductive reactance of the TCR varies and causes rapid reactive power exchange between the TCR and the system. Depending on the system conditions 4-86
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inductive or capacitive vars may be needed. To meet this requirement the variable inductor is usually connected in parallel with a fixed capacitor. A metal-oxide varistor is also connected in parallel for overvoltage protection.
MOV Xc
I line
Xl Fig. 4.26 Per phase TCSC module
Firing angles are allowed to vary between 90° and 180°. For a certain firing angle the variable inductive reactance of the TCR equals in absolute value the capacitive reactance of the fixed capacitor Xc causing a resonance. Thyristors are fired sufficiently far away from the resonance value to avoid problems with control (resonance region limits). The TCSC module is modeled as a single variable reactance with firing angle (or reactance) limits. Additional limitations can be imposed on the voltage drop and on the line current (in case of line current control).
A
X max E
VMax I Max
Cap. operation
Xc Not available 0 ~Xl
B C
G
ILine
Ind.operation
VMax F D
X TCSC
X min
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Fig. 4.27 XTCSC versus line current characteristic
The figure above depicts the steady-state TCSC equivalent reactance XTCSC versus line current characteristic, where the following physical and operating limitations are displayed: • A,D: resonance region limitation • B: firing angle limitation (=180°) (XTCSC is equal to the capacitor’s reactance Xc) • C: firing angle limitation (=90°) (XTCSC is almost equal to the inductor’s reactance Xl) • E,F: upper voltage limits for capacitive and inductive operation • G: maximum allowed current in continuous operation A TCSC can either operate in the capacitive or in the inductive region. That means, that Xmin and Xmax, must be entered both as negative (Cap. operation) or both as positive (Ind. operation) values. As shown in 4.26a in case of one-module operation there is a range of values for XTCSC that cannot be controlled. Figure 4.26b depicts the same characteristic with two identical modules connected in series with half the rating (half the Xl and Xc reactances) of the original (one) module. The two modules are independently controlled. The control gap is now partially covered and for increasing number of modules the operating area of the TCSC covers the entire region enclosed by the dashed curve in Figure 4.26b. Remark In general (in multi-module operation) each module can have a different firing angle. Therefore in the results there is no firing angle value (firing angle = 0), whereas there is a value for the total effective reactance and voltage drop.
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UPFC This chapter describes the parameters of the Data Input Dialog of a UPFC (Unified Power Flow Controller) and the corresponding UPFC model. UPFC-Parameters Name
Name of element.
Vser min
LMDR
Minimum series voltage magnitude in % of the bus nominal voltage.
Vser max
LMDR
Maximum series voltage magnitude in % of the bus nominal voltage.
Iq min
LMDR
Minimum shunt current in A.
Iq max
LMDR
Maximum shunt current in A.
P max
LMDR
Maximum power through the DC link (Px) in MW.
Connecting Transformers Leakage Impedances Series Tr. R
LMDR
Leakage resistance of series transformer in Ohm.
Series Tr. X
LMDR
Leakage reactance of series transformer in Ohm.
Shunt Tr. R
LMDR
Leakage resistance of shunt transformer in Ohm.
Shunt Tr. X
LMDR
Leakage reactance of shunt transformer in Ohm.
Line Flow Regulation at port 2 P
LMDR
Control value for the active line flow P2.
Q
LMDR
Control value for the reactive line flow Q2.
Voltage Regulation Sending end LMDR V set
Control value for the voltage magnitude of the sending end.
Receiv. end V min
LMDR
Minimum voltage magnitude at the receiving end.
Receiv. end V max
LMDR
Maximum voltage magnitude at the receiving end.
UPFC-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
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UPFC-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
UPFC-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
UPFC-More… Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (UPFC)
ILine
U1 IQ
- UT +
Px (+)
Shunt connected converter
U2
P2,Q2
Series connected converter
Fig. 4.28 Unified Power Flow Controller (UPFC)
The basic structure of the UPFC implementation is shown in the figure above. UPFC consists of two voltage-sourced converters, one connected in shunt with the line through a transformer and one connected in series with the line through a second transformer. The two converters are operated from a common DC link, provided by a DC storage capacitor. The series connected converter injects a controlled voltage UT in series with the line. The phase 4-90
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angle of the phasor UT can be chosen independently of the line current and the magnitude is variable between zero and a maximum UTmax. The series converter exchanges real and reactive power with the transmission system. The reactive power can be generated independently from the series converter, while the real power has to be supplied from the network. That is the primary function of the shunt converter, which is controlled in such a way as to provide at its DC terminal the real power needed by the series converter. A secondary function of the shunt converter is to generate or absorb reactive power for regulation of the AC terminal voltage U1. Apparent power exchanged through series injected voltage: Sxser = Pxser + j•Qxser = UT • (ILine)* (1) Apparent power exchanged through shunt current: Sxshu = Pxshu + j•Qxshu = U1 • (IQ)* (2) In (1): Pxser > 0 (Qxser > 0) means that active (reactive) power is injected to the system. In (2): Pxshu > 0 (Qxshu > 0) means that active (reactive) power is drawn from the system. The UPFC model ignores device losses, therefore: Pxshu = Pxser = Px The reactive powers Qxser, Qxshu however can be independently produced by the two converters. With nonzero transformer impedances the equations (1) and (2) become: Apparent power exchanged through series injected voltage: Sxser = Pxser + j•Qxser = √3 UT • (ILine)* (1)’ Apparent power exchanged through shunt current: Sxshu = Pxshu + j•Qxshu = √3 U1 • (IQ)* - 3 |IQ|2 (Rshu +jXshu) (2)’
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Network Feeder This chapter describes the parameters of the Data Input Dialog of a network feeder and the corresponding network feeder model. Network Feeder-Parameters Name
Name of element.
Type
Applicable only with a network feeder library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Sk" max, min SMHP
Maximum and minimum initial symmetrical short circuit power in MVA (Sk" =√3·Un·Ik").
Ik" max, min
SMHP
Maximum and minimum initial symmetrical short circuit currents in kA (Ik" = Sk"/(√3·Un)).
R(1)/X(1) max, min
SMHP
Maximum and minimum ratio of positive sequence resistance of feeder to its positive sequence reactance.
Z(0)/Z(1) max, min
SP
Maximum and minimum ratio of zero sequence impedance to its positive sequence impedance.
R(0)/X(0) max, min
SP
Maximum and minimum ratio of zero sequence resistance of feeder to its zero sequence reactance.
C
H
Capacitance of network in µF.
Operational data LF-Type
LMDR
Node type for load flow calculation. Possible values are: • "SL": Slack node. Input of values "U oper" and "Uw oper" compulsory (see below). • "PQ":P,Q-node. Input of values "P" and "Q" compulsory (see below).
U oper
LMDR
It's the voltage, in % with respect to Un, which the Slack has to regulate, if the LF-Type will be "SL".
Uw oper
LMDR
Angle of voltage in degrees, if the LF-Type will be "SL".
Slack portion LMDR
The portion in % of the total slack active power, which has to be supplied by this network feeder. This value is only considered, if the load flow is calculated with distributed slack or with zone/area control (see load flow calculation parameters). The sum of all slack portions in the network or zone/area may be unequal to 100%. In this case the program internally scales the
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slack portion proportionally, so that the effective sum is 100%. P
LMDR
Input of active power in MW, if the LF-Type will be "PQ". For generating power the value for P must be given as positive value. For loads the value must be given as negative value.
Q
LMDR
Input of reactive power in Mvar, if the LF-Type will be "PQ". Positive value means generation of inductive reactive power (over excited generator); negative value means consumption of inductive reactive power (under excited generator).
Network Feeder-Info The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Network Feeder-Reliability The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Network Feeder-User Data The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Network Feeder-More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description NEPLAN User's Guide V5
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Element Data Input and Models
can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (Network Feeder) The following figure shows the model of a network feeder. R
X
R
C
X
Fig. 4.29 Model of a network feeder for short circuit calculation (above) and for harmonic analysis (below)
The model parameters of the positive and zero sequence are calculated as follows:
Positive sequence
Zero sequence
Z(1) = c·Un²/Sk"
Z(0) = Z(1)· (Z(0)/Z(1))
δ = arctan(X(1)/R(1))
δ0 = arctan(X(0)/R(0))
R(1) = Z(1)·cos(δ)
R(0) = Z(0)·cos(δ0)
X(1) = Z(1)·sin(δ) Z(1) = R(1) + j·X(1)
X(0) = Z(0)·sin(δ0) Z(0) = R(0) + j·X(0)
For harmonic analysis only the positive sequence is considered and the impedance Z(1) will be calculated as a mean value of the minimal and maximal short circuit power.
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Synchronous Machine This chapter describes the parameters of the Data Input Dialog of a synchronous machine and the corresponding model. Synchronous Machine - Parameters
Name
Name of element.
Type
Applicable only with a synchronous machine library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Ur
SMHPD Rated voltage in kV.
pUr
SP
Sr
SMHPD Rated power in MVA.
Cos(phi)
SMP
Power factor.
Ufmax/Ufr
SP
Ratio of highest possible excitation-voltage to rated excitation at rated load and power factor.
xd sat.
SP
Synchronous reactance in % with respect to Sr and Ur (saturated value). Recommended value: Turbo-SM: 120 .. 270 Salient pole-SM: 70 .. 130
xd' sat
SMHP
Saturated transient reactance in % with respect to Sr and Ur. This value will only be used for short circuit calculations according to ANSI. Recommended value: Turbo-SM: (1.4 .. 1.7)* xd" Salient pole with amortisseur winding: 20 .. 45%
xd" sat
SMHP
Saturated subtransient reactance in % with respect to Sr and Ur. Recommended value: Turbo-SM: 9 .. 22 (large values when large Sr) Salient pole-SM: 12 .. 30 (large values if slow speed rotor with large Sr)
Ikk
SP
Steady state short circuit current in kA of generator with compound excitation during 3-phase short circuit. • Ikk=0: Generator with no compound excitation. • Ikk0: Generator with compound excitation.
NEPLAN User's Guide V5
If the generator voltage Ug is permanently higher than the rated voltage Ur, this should be indicated with a deviation in %. Only necessary for Short Circuit calculation by IEC60909 (2001).
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Ikk will be used to calculate the minimum steady state short circuit current for generators with compound excitation. Mue
SP
The factor mue will be used for the calculation of breaking currents. • mue=0 : mue value will be calculated according to IEC standard. • Mue0: mue will be set to the input value.
RG
SMHP
Equivalent resistance of generator in Ohm. RG is considered for the calculation of all currents except for the calculation of the peak current ip. For ip-calculation a fictive value according to IEC will be taken, no matter which calculation method is used (see Description of the Model (SC)).This fictive value for RG is also used for the calculation, if RG is set to 0.
X(2)
SP
Negative sequence reactance given by x(2)=0.5(xd"+xq") in % with respect to Sr and Ur. Recommended value: x(2) = xd".
X(0)
SP
Zero sequence reactance of the synchronous machine in % with respect to Sr and Ur. Recommended value: x(0) = (0.4 .. 0.8) xd".
Amortisseur SP winding
Checkbox, indicates if the synchronous machine has an amortisseur (damper) winding or not.
Motor
SP
Indicates, if the synchronous machine works as motor. This input influences the minimum short circuit current according to IEC909.
Rotor type
SP
Indicates the type of the synchronous machine (salient pole or round rotor).
Unit generator
SP
Checkbox, indicates whether the machine is part of a power station unit.
Earthing
SP
Indicates de type of earthing of the generator.
Re, Xe
SP
For impedance earthing: Generator star point earthing resistance and reactance in Ohm.
Active
SP
The user can define, which portion in % of the earthing impedance is active.
Generation costs
L
For the OPF-Simulation it's possible to minimize the generation costs. These costs are represented by the following quadratic curve: C(P) = a*P2 + b*P + c The following parameters have to be entered:
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•
a: quadric factor in unit of currency (e.g. US$) to MW2 • b: linear factor in unit of currency to MW2 • c: constant factor in unit of currency • P is the active power produced by the generator in MW
Synchronous Machine - Limits
Name
Name of element.
P min
LDR
Minimum allowable active power in MW. If the synchronous machine works as generator, P min is a positive value and means the minimum amount of active power, which the machine must produce. If the synchronous machine works as motor, P min is a negative value and means the maximum amount of active power, which the machine can consume (see below).
P max
LDR
Maximum allowable active power in MW. If the synchronous machine works as generator, P max is a positive value and means the maximum amount of active power, which the machine can produce. If the synchronous machine works as motor, P max is a negative value and means the minimum amount of active power, which the machine must consume (see below).
Q min
LDR
Minimum allowable limit for the reactive power Q in Mvar, when LF-Type equal "PV". If Q runs below this value during LF-calculation, Q will be set Q = Q min (only for Newton-Raphson method). If the synchronous machine works over excited, Qmin is a positive value and means the minimum amount of inductive reactive power, which the machine must produce. If the synchronous machine works under excited, Qmin is a negative value and means the maximum amount of inductive reactive power, which the
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Element Data Input and Models
machine can consume. Q max
LDR
Maximum allowable limit for the reactive power Q in Mvar, when LF-Type equal "PV". If Q runs beyond this value during LF-calculation, Q will be set Q = Q max (only for Newton-Raphson method). If the synchronous machine works over excited, Q max is a positive value and means the maximum amount of inductive reactive power, which the machine can produce. If the synchronous machine works under excited, Q max is a negative value and means the minimum amount of inductive reactive power, which the machine must consume.
Cosphi control
P lim
LDR
Break point of the characteristic curve.
Cosphi max LDR
Maximum Cosphi of the feasible domain of "Cosphi oper". The check box "Capacitive" selects between inductive or capacitive operation.
Cosphi min LDR
Minimum Cosphi of the feasible domain of "Cosphi oper". The check box "Capacitive" selects between inductive or capacitive operation.
Capability Curve
Curve
LDR
The user can define himself a PQ-curve. Depending on the active power P, the limits Qmin and Qmax of the reactive power will be defined by this Capability Curve for a LF-type PV. Points of this curve may be entered with "Insert", and removed with "Delete". The whole (Pmin, Pmax) range must be included in the capability list.
Active during calculation
LDR
During LF-calculation the PV-generator is checking if the necessary reactive power Q, to guarantee the nodevoltage U oper, is between Qmin and Qmax. If the Capability Curve is active, the program is using the limits defined in this curve.
Synchronous Machine - Operational
Name LF-Type
4-98
Name of element. LDR
Type of node for load flow calculation. Possible values: NEPLAN User's Guide V5
Element Data Input and Models
•
"PQ": P,Q-node. Input of the values "P" and "Q" compulsory (see below). • "PV": P,V-node. Input of the values "U oper" and "P" compulsory (see below). • "SL": Slacknode. Input of the value "U oper" compulsory (see below). Voltage angle will be set to 0. • "PC": P,C-node. Input of the values "P" and "Cosphi oper" compulsory (see below). Operating Mode
()
Based on the operational data, the operating mode indicates if the synchronous machine is working as a generator or as a motor and if it is over- or underexcited.
U oper
LD
Amount of voltage in % related to Un, if LF-Type equal "PV" or "SL". The generator will be voltage-regulated.
Uw oper
LMDR
Angle of voltage in degrees, if the LF-Type will be "SL".
PGen
LMDR
Input of active power in MW, if the LF-Type will be "PV", "PQ", or "PC". For generating power the value for P must be given as positive value. For loads the value must be given as negative value. This value will be multiplied by the scaling factor to receive the operational power Poper.
QGen
LMDR
Input of reactive power in Mvar, if the LF-Type will be "PQ". Positive value means generation of capacitive reactive power (overexcited generator); negative value means consumption of capacitive reactive power (under- excited generator). This value will be multiplied by the scaling factor to receive the operational power Qoper.
Effective scaling factor for P
LMDR
Indicates the total scaling factor for the active power of the synchronous machine. It is calculated by the product of the network, of the zone and of the assigned scaling factor for P: fep=fnp*fzp*fap
Effective scaling factor for Q
LMDR
Indicates the total scaling factor for the reactive power of the synchronous machine. It is calculated by the product of the network, of the zone and of the assigned scaling factor for Q: feq=fnq*fzq*faq
Scaled values LMDR
For PV, PQ and PC LF-types, the effective active power P, to be produced or consumed, is indicated. For PQ LF-typ, additionally the effective reactive power Q, to be produced or consumed, is indicated.
NEPLAN User's Guide V5
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Element Data Input and Models
The scaled values Poper and Qoper are calculated with P and Q and the respective scaling factors: Poper= P* fep ; Qoper= Q* feq Remote LDR controlled bus
In case of a voltage regulated generator (LF-Type: PV) the node to be regulated can be entered here. If this input field is empty, the voltage of the generator node will be regulated. The remote control is only working for nodes, which are connected with the generator node through elements. In case of a three-windings transformer remote control is only possible for a generator connected at the secondary node. The tertiary node must have no load and no generation (I3 = 0.0 A)
Static
The static in Hz/MW of the generator can be entered here. The static S is defined as follows: Static: S = -(f0 – f’) / (Poper – P’) Poper: Scaled value for active power P’: Calculated active power for operating frequency f f0: Nominal system frequency in Hz. f’: Operating frequency in Hz.
LDR
The calculated active power at operating frequency f’ is P’ = P0 + (f0 – f’) / S. The operating frequency f’ can be entered in the load flow calculation parameters. Slack portion
LDR
The portion in % of the slack active power, which has to be generated or consumed by this synchronous machine. This value is only considered, if the load flow is calculated with distributed slack or with area interchange control (see load flow calculation parameters). The sum of all slack portions in the network or zone/area may be unequal to 100%. In this case the program internally scales the slack portion proportionally, so that the effective sum is 100%.
Qpv
LDR
The portion of reactive power in %, which has to be generated or consumed by this machine in case of PVnode (with or without remote control) in case of different machines regulating the voltage of the same node (see below). The sum of all Qpv portions for the regulated node may be unequal to 100%. In this case the program internally scales the Qpv portion proportionally, so that the effective sum is 100%.
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Cosphi control (LF type "PC")
Cosphi oper
LDR
Cosphi-value of the generator, used for the following "Cosphi control" options: • Cosphi oper remains constant for the option "Cos(phi) constant". • Cosphi oper is used as initial value for the options "Reactive power" and "Reactive/active power".
Capacitive
LDR
The check box "Capacitive" selects between inductive or capacitive operation.
Cos(phi) constant
LDR
The control input "Cosphi oper" is constant.
Cos(phi) characteristic curve
LDR
"Cosphi oper" changes dependent on the active power according to a characteristic curve (see Cosphi characteristic curve).
Reactive power
LDR
If the corresponding node voltage becomes greater than its maximum value U max, "Cosphi oper" changes so, that the asynchronous machine is lowering the reactive power production, respectively increasing the consumption of inductive reactive power. "Cosphi oper" must not leave the feasible domain defined by "Cosphi min" and "Cosphi max".
Reactive/ active power
LDR
Same behavior as type "Reactive Power". If "Cosphi oper" can't be adjusted further, the active power is reduced so that the node voltage doesn't exceed Umax.
Synchronous Machine – Scaling Factors
Operating Mode
LMDR Indicates if the synchronous machine is working as a generator or motor, depending on the sign of the active power P. For the generator mode, P has to be positive, for motor mode negative.
Scaling factor LMDR Displays the predefined scaling factor of P and Q for of network the network. Depending on the Operating Mode, these are the scaling factors for generation or load. Predefined scaling factors may be changed in “Edit Data - Operational Data“ (see chapter “Menu Options”). Scaling factor LMDR Displays the predefined scaling factors of P and Q for of zone the zone. Depending on the Operating Mode, these are the scaling factors for generation or load. Predefined NEPLAN User's Guide V5
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scaling factors may be changed in "Edit - Data Operational Data" (see chapter “Menu Options”). Assigned scaling factor
LMDR Displays the scaling factors of P and Q, assigned to this synchronous machine. It's a total of the assigned user defined scaling factors (see below).
Effective scaling factor
LMDR Displays the effective scaling factors of P and Q for this synchronous machine. It's the product of all scaling factors: fe=fn*fz*fa
Assign user defined scaling factors
Table
LMDR The user has the possibility to assign one or more user defined scaling factors. Every user defined scaling factor may consist of a constant factor (P-factor, Qfactor) and a time dependent factor (characteristics). If there are various user defined scaling factors in the table, a total factor has to be calculated with help of the portion. The portion may be defined directly in the table and it has to be considered that the total of all portions can’t exceed 100%. That's why it's necessary to lower first a portion before increasing an other one. The total of all assigned user defined scaling factors is displayed in the fields "Assigned scaling factor” and it’s calculated as follows: faP= p1 * Pfactor1 + p2 * Pfactor2 + … faQ= p1 * Qfactor1 + p2 * Qfactor2 + … p = Portion For simulations with the module “Load Flow with Load Profiles” the time dependent scaling factor gets into the equation: faP= p1 * Pfactor1 * Pfactor_t1(t) + p2 * Pfactor2 * Pfactor_t2(t) + … faQ= p1 * Qfactor1 * Qfactor_t1(t) + p2 * Qfactor2 * Qfactor_t2(t) + …
Insert
LMDR Inserts in the table a time dependent scaling factor, which can be chosen from a list of all defined factors.
Remove
LMDR Removes the marked scaling factor from the table.
Define scaling LMDR Enters in the Scaling Factors Editor, where the user factors may define Scaling Factors and the time-dependent characteristic curves (see chapter “User Defined Scaling Factors” on page 4-151). Show characteristic 4-102
LMDR Shows the time dependent characteristic curves of the Scaling Factor Type marked in the table. NEPLAN User's Guide V5
Element Data Input and Models
Synchronous Machine – Dynamic
Name
Name of element.
Ur
SMHPD Rated voltage in kV.
Sr
SMHPD Rated power in MVA.
Model
D
Indicates the model of the synchronous machine for dynamic simulation. Possible models are: - Classical - Transient - Subtransient
Rotor type
D
Indicates the rotor type of the synchronous machine.
H
D
Inertia constant of the generator and turbine.
D
D
Mechanical damping in MW/Hz.
R
D
Stator resistance
Machine reactances
Xd
D
d-axis synchronous reactance in % with respect to Sr and Ur.
Xq
D
q-axis synchronous reactance in % with respect to Sr and Ur.
Xd'
D
d-axis transient reactance (unsaturated) in % with respect to Sr and Ur.
Xq'
D
q-axis transient reactance (unsaturated) in % with respect to Sr and Ur.
Xd"
D
d-axis subtransient reactance (unsaturated) in % with respect to Sr and Ur.
Xq"
D
q-axis subtransient reactance (unsaturated) in % with respect to Sr and Ur.
Xc
D
Characteristic reactance in % with respect to Sr and Ur. This value is used to calculate the field values. If Xc is unknown, set Xc = Xp.
Xl
D
Stator leakage reactance or Potier reactance in % with respect to Sr and Ur.
Time constants
Type
D
NEPLAN User's Guide V5
Indicates, if the time constants are entered for open circuit or short circuit. The corresponding values are calculated.
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Element Data Input and Models
Tdo'
D
d-axis transient open-circuit time constant in s.
Tqo'
D
q-axis transient open-circuit time constant in s.
Tdo"
D
d-axis subtransient open-circuit time constant in s.
Tqo"
D
q-axis subtransient open-circuit time constant in s.
Td'
D
d-axis transient short-circuit time constant in s.
Tq'
D
q-axis transient short-circuit time constant in s.
Td"
D
d-axis subtransient short-circuit time constant in s.
Tq"
D
q-axis subtransient short-circuit time constant in s.
' = 0 must be set. For salient pole machines x'q = xq and/or Tq0 Synchronous Machine – Saturation (D)
Saturation parameters may be inserted for d-axis and q-axis. Saturation
D
Indicates if the saturation is considered for the calculation.
Type
D
Indicates, if the saturation will be described with the field currents Ia, Ib, Ic or the parameters A and B (see below). The value for Ia must always be entered. Possible values are: - Field currents Ia, Ib, Ic - Parameter A, B The corresponding values are calculated.
Ia
D
Exciter current in A on the air gap characteristic at nominal voltage. This value must always be entered, even if the saturation is described by the parameters A and B.
Ib
D
Exciter current in A on the open-circuit characteristic at nominal voltage (see below).
Ic
D
Exciter current in A on the open-circuit characteristic at 120% of nominal voltage (see below).
A, B
D
Parameter values or saturation factors (see below).
The saturation of a synchronous machine is defined by its open-circuit characteristic. The graph will be described with the parameters Ia, Ib and Ic of the air gap and the open-circuit characteristic:
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terminal voltage air gap characteristic 120 %
open-circuit characteristic
100 %
0% Ia
0
Ib
Ic
field current
Fig. 4.30 Air gap and open circuit characteristic
With these currents Ia, Ib and Ic, the saturation factors A and B can be calculated, which are used to reproduce the open-circuit characteristic approximately. I Open −circuit = I Airgap • (1 + A ⋅ e B (u −0.8 ) )
with
(I b − I a )2 A= I a ⋅ (I c − 1.2 ⋅ I a )
I − 1.2 ⋅ I a and B = 5 • ln c 1.2 ⋅ (I b − I a )
Synchronous Machine – Info
The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Synchronous Machine - Reliability
The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Synchronous Machine - User Data
The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3. NEPLAN User's Guide V5
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Synchronous Machine - More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Portions of Reactive Power for PV-Generators
The sum of the Q portions for one PV-node doesn’t need to be 100%. The program calculates proportionally the effective portion factor. PV-Node G
Q pv = 40% ! (40*100/120=33.3%)
G
Q pv = 50% ! (50*100/120=41.7%)
G
Q pv = 30% ! (30*100/120=25%)
PV-Node, Remote control
4-106
G
Q pv = 40% ! (40*100/120=33.3%)
G
Q pv = 50% ! (50*100/120=41.7%)
G
Q pv = 30% ! (30*100/120=25%)
NEPLAN User's Guide V5
Element Data Input and Models
P- and Q-limits of the Machine
The limits must be entered as follows:
Motor
Generator
0
P min
P max
Under excited
0
Over excited
Q max
Q min
Cosphi characteristic curve (SM) Cosphi oper Cosphi max
Cosphi min P P min
P lim
P max
Fig. 4.31 Cosphi characteristic curve
Description of the Model (SC) (SM) R
X
NEPLAN User's Guide V5
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Element Data Input and Models
Fig. 4.32 Model of a synchronous machine for short-circuit calculation
The model parameters of the positive, negative and zero sequence are calculated as follows: Positive sequence
Negative sequence
R = Rf X = xd"·Ur²/(100·Sr)
R = Rf X = x(2)·Ur²/(100·Sr)
Zero sequence
R = Rf + 3·RE X(0) = x(0)·Ur²/(100·Sr) X = X(0) + 3·XE The parameter RG (resistance) is set in function of Ur and Sr according to IEC (RG of the Data Input Dialog is used only for the calculation of iDC and only if RG is unequal to 0): Rf = 0.05·Xd" (for Ur > 1 kV and Sr >= 100 MVA) Rf = 0.07·Xd" (for Ur > 1 kV and Sr < 100 MVA) Rf = 0.15·Xd" (for Ur predefined curves). With these values the program calculates R2 and X2 for each given slip, when the Calculate button has been pressed. For every slip between the given values, the program interpolates linearly R2 and X2, to get a complete model. To compare the calculated curves with the manufacturer’s (predefined) curves, it is possible to display both in the same diagram (button “Calculate”).
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Asynchronous Machine – Info
The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Asynchronous Machine - Reliability
The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Asynchronous Machine - User Data
The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Asynchronous Machine - More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6. Start-up device
Start-up
M**
Indicates, whether the machine will be started up during motor starting calculation or not.
t start
M**
Time in seconds after which the motor will be start-up.
Start-up device
**
M
NEPLAN User's Guide V5
Starting device. Possible values: - Direct: Direct start-up - YD: Wye-Delta start-up - Z stator: Start-up impedance - R rotor: Rotor resistance start-up 4-125
Element Data Input and Models
- Transformer: Start-up with auto-transformer - C: Start-up with compensation M**
There are two options to by-pass the start-up device. It can be switched after reaching a certain time or a certain slip in %. When switching after time, the delay of start-up tstart will be considered. The switching time will be therefore t = tstart + tswitch. If direct starting this value has no meaning.
Ur1, Ur2
M**
Transfomer rated voltage at primary and secondary side in kV. This input is only relevant in case of transformer start-up.
Sr
M**
Transfomer rated power in MVA. This input is only relevant in case of transformer start-up.
uRr, ukr
M**
Transformer copper losses and short circuit voltage in % This input is only relevant in case of transformer start-up.
Rs
M**
Real part of stator start-up impedance in Ohm. This input field is only important if the start-up device will be "Z stator".
Xs
M**
Imaginary part of stator start-up impedance in Ohm. This input field is only important if the start-up device will be "Z stator".
M**
Start-up rotor resistance in Ohm. This input is only relevant in case of rotor resistance start-up.
M**
Reactive power in kvar, which will be compensated at voltage Un. This input is only relevant in case of capacitor start-up. The capacity C, which will be inserted parallel to the motor, is: C = Qc / Un2
M**
The values C, Rr or Zs (Rs, Xs) will be cascade during the start-up, if the start-up type will be "C", "R rotor" or "Z stator". The values will be changed as follows: Ci = C - (i - 1) * C / n Rri = Rr - (i - 1) * Rr / n
t switch, s switch
Transfomer
Z stator
R rotor
Rr C start
Qc
Cascading
n cascade
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Zsi = Zs - (i - 1) * Zs / n The running variable i (cascade i) begins at 1 and is incremented by 1 during the start-up, according to the n time resp. slip areas (see "t switch", "s switch").
Mechanical Load
H J
M** **
Inertia constant.
M
Moment of inertia in kgm².
Given as
M**
The load torque characteristic may be entered by a Table or a Parabola.
Table
M**
The Table can be chosen from a Library.
Load torque
Parabola
M0, M1, M2 M**
Nm
M**
Parameters of quadratic starting characteristic (Parabola) Mload(s)=M0+M1*(1-s)+M2*(1-s)² in Nm (s: slip) or related to the rated torque of the motor (see below). Gives the units of the load torque: Nm (checkbox checked) or related to the rated torque of the motor.
Load Table Entries
s, M load
M**
The load torque may be entered as a table with user defined points.
Remark: The load torque is described by the equation: Ml = M0 + (1 - s) · M1 + (1 - s) 2 · M2 (parabola) or Ml = Ml(s) (characteristic (table entries)) The input of Ml(s) is more significant as the input of M0, M1 and M2.
Voltage drop calculation: All values marked with (M*) are necessary. Motor starting calculation: All values marked with (M*) or (M**) are necessary.
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Cosphi characteristic curve (AM) Cosphi oper Cosphi max
Cosphi min P P min
P lim
P max
Fig. 4.36 Cosphi characteristic curve
Description of the Model (SC) (AM) R
X
Fig. 4.37 Model of asynchronous machine for short-circuit calculation
The model parameters of the positive sequence are calculated as follows: Positive sequence: Z = η·cos(phi)·Ur² / [Prmech·(Ia/Ir)·n]
n: number of ASM
X = Z / √((Rm/Xm)²+1) R = X · (Rm/Xm)
The ratio Rm/Xm will be set according to IEC, if Rm is set to 0: • Rm/Xm = 0.1 for high voltage motors with active power Pr per Pole pair >= 1MW • Rm/Xm = 0.15 for high voltage motors with active power Pr per Pole pair < 1MW 4-128
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•
Rm/Xm = 0.42 for low voltage motors
The impedance Z = R + j·X of zero sequence is set to infinity. Remark:
For a thyristor fed motor (corresponding checkbox must be checked) the following values are assumed: • Ia/Ir = 3 • Rm/Xm = 0.1
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PS-Block This chapter describes the parameters of the Data Input Dialog of a Power Station Block and the corresponding model. PS-Block – Parameters
Name
Name of element.
Type
Applicable only with a "Power Station Block" library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Unit transformer
Ur1, Ur2
SMHP
Rated voltage of the node 1 and 2 in kV.
Sr
SMHP
Rated power of the transformers in MVA.
Vector group SP
Wiring of the windings in node 1 and 2. Default-value: YY.00 .
uRr(1)
SMHP
Positive sequence copper losses in % with respect to Sr (of transformer) and Ur1.
ukr(1)
SMHP
Positive sequence short circuit voltage in % with respect to Sr and Ur1.
uRr(0)
SP
Zero sequence copper losses in the windings 1 and 2 in % with respect to Sr and Ur1.
ukr(0)
SP
Zero sequence short circuit voltage in % with respect to Sr and Ur1.
Earthing
SP
Indicates de type of earthing of the unit transformer.
Re1, Xe1
SP
Real- and imaginary part of earthing impedance in Ohm, on primary side (winding 1).
Unit generator
Sr
SMHP
Rated power of generator in MVA.
xd" sat
SMHP
Saturated subtransient reactance in % with respect to Sr (of generator) and Ur2.
x(2)
SP
Negative sequence reactance x(2)=0.5 (xd"+xq") in % with respect to Sr (of generator) and Ur2.
Cos(phi)
SMHP
Power factor.
xd sat.
SP
Synchronous reactance in % with respect to Sr (of generator) and Ur (saturated value).
Ufmax/Ufr
SP
Ratio of highest possible excitation voltage to rated
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excitation at rated load and power factor. Turbo
SP
Checkbox to indicate the type of the synchronous machine.
Operational data
P oper
LMDR
Input of active power in MW. For generating power the value for P must be given as positive value. For loads the value must be given as negative value.
Q oper
LMDR
Input of reactive power in Mvar. Positive value means generation of capacitive reactive power (overexcited generator); negative value means consumption of capacitive reactive power (under excited generator).
PS Block – Info
The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
PS Block - Reliability
The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
PS Block - User Data
The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
PS Block - More… Frequency dependence…
By pressing this button of the More tab, the Frequency dependence input parameters can be entered. They are only used for harmonic analysis. The description can be found in “Frequency dependence” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-4. Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description NEPLAN User's Guide V5
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can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
Description of the Model (PS Block) 3 · Ze1
Z
R G
T
X
G
t:1 Fig. 4.38 Model of power station block in the positive and negative system
The model parameters of the positive and negative sequence are calculated as follows: Positive sequence
Negative sequence
ZT = ukr(1)·Ur1²/(Sr·100) RT = uRr(1)·Ur1²/(Sr·100) XT = √(ZT²-RT²) ZT = RT + j·XT RG = Rf XG = xd"·Ur²/(100·SrG) ZG = RG + j·XG
ZT = ukr(1)·Ur1²/(Sr·100) RT = uRr(1)·Ur1²/(Sr·100) XT = √(ZT²-RT²) ZT = RT + j·XT RG = Rf XG = x(2)·Ur²/(100· SrG) ZG = RG + j·XG
The model of the power station block in the zero sequence depends on the vector group of the transformer. Because the star point of the transformer is not grounded on generator side, the only transformers with vector groups ZY and YD can lead a zero sequence current.
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3 · Ze
ZT
Fig. 4.39 Model of power station block (vector groups YD or ZY) in the zero sequence
Zero sequence
ZT = ukr(0)·Ur1²/(Sr·100) RT = uRr(0)·Ur1²/(Sr·100) ZT = RT + j·XT Ze1 = Re1 + j·Xe1
XT = √(ZT²-RT²)
The parameter RG (resistance) is set in function of Ur and Sr according to IEC: RG = 0.05·xd" RG = 0.07·xd" RG = 0.15·xd"
(for Ur > 1 kV and Sr >= 100 MVA) (for Ur > 1 kV and Sr < 100 MVA) (for Ur u a1
R( u )
u − u 2 ;0 = MAX 1 − b1 u b1 − u b 2 =1 u − u 2 ;0 = MAX 1 − a1 u a1 − u a 2
For the values
ub1 = 0.9 pu ; ub2 = 0.75 pu ua1 = 1.1 pu ; ua2 = 1.25 pu the behavior of the reduction factor is illustrated below:
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Voltage dependence of the reduction factor R(u)
ua1
ub1
1
0 0.75 ub2
0.9
1.0
1.1
1.25
u [pu]
ua2
Fig. 4.41 Voltage dependence of the reduction factor
The reduction factor is used only in the composite model. R(u) is reducing the constant current and the constant power factors by multiplication:
u u 2 ∆f p = p0 ⋅ R( u ) ⋅ c sp + R( u ) ⋅ cip ⋅ + c zp ⋅ 2 ⋅ 1 + ⋅ Fp u0 u0 f0 u u 2 ∆f q = q0 ⋅ R( u ) ⋅ csq + R( u ) ⋅ ciq ⋅ + c zq ⋅ 2 ⋅ 1 + ⋅ Fq u0 u0 f0 c zp = 1 − R( u ) ⋅ cip − R(u ) ⋅ c sp c zq = 1 − R( u ) ⋅ ciq − R(u ) ⋅ c sq
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DC Load This chapter describes the parameters of the Data Input Dialog of a DC Load and the corresponding model. DC Load – Parameters
Name
Name of element.
Type
Applicable only with a load library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Regulation
()
Type of node for load flow calculation. Possible values: • "P": P-node. Input of the values "Pset" compulsory (see below). • "I": I-node. Input of the values "I set" compulsory (see below). • "R": R-node. Input of the values "R set" compulsory (see below).
P set
()
Consumed DC power at node in MW.
I set
()
Amount of DC load current in kA.
R set
()
Load DC resistance in Ohm.
DC Load – Info
The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
DC Load - Reliability
The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
DC Load - User Data
The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
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DC Load - More… Investment Data…
By pressing this button of the More tab, the Investment Data input parameters can be entered. They are only used for investment analysis. The description can be found in “Investment Analysis” of chapter “Data Input Dialogs of Network Elements”-“Element - More…” on page 4-6.
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Line Load This chapter describes the parameters of the Data Input Dialog of a Line Load and the corresponding model. There are two possibilities to assign a line load to a line. If the user wants the line load to be represented graphically, the line load symbol has to be chosen in the Symbol Window and pasted on the respective line. The Data Input Dialog appears. If a graphical representation of the line load isn’t necessary, it’s possible to enter the line loads in the Data Input Dialog of the respective line by pressing the Line loads button in the More… tab. In this window also the line loads, which have been entered graphically, appear. The Input-Data is shown in tabular form. By double clicking on the number of the respective line load, the Data Input Dialog opens. Also more than one line load may be entered per line.
Line Load – Parameters
Name
Name of element.
Type
Applicable only with a line load library. Pressing the button "…", the type may be chosen and the data can be transferred from the predefined library.
Lf-Type
()
Type of node for load flow calculation. Possible values: • "PQ": P,Q-node. Input of the values "P" and "Q" compulsory (see below). • "PC": P,C-node. Input of the values "P" and "cos(phi)" compulsory (see below). • "IC": I,C-node. Input of the values "I" and "cos(phi)" compulsory (see below). • "PI": P,I-node. Input of the values "P" and "I" compulsory (see below). • "SC": S,C-node. Input of the values "S" and "cos(phi)" compulsory (see below). • "EC": E,C-node. Input of the values "E", "Velander factor 1", "Velander factor 2" and "cos(phi)" compulsory (see below).
Units
()
Indicates if the values P, Q and I are given for low or high voltage. Possible values:
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• •
HV: High voltage LV: Low voltage
The default value can be given in the Edit Options mask (see "Edit Options" in chapter "Menu Insert"). When introducing a new load the default unit will be taken. S
()
Consumed power in MVA or kVA. Dependent on the phase connectivity (see Info tab) the value must be entered as phase value.
P
()
Consumed active power in MW or kW. Dependent on the phase connectivity (see Info tab) the value must be entered as phase value.
Q
()
Consumed reactive power in Mvar or kvar. Dependent on the phase connectivity (see Info tab) the value must be entered as phase value.
I
()
Amount of load current in kA or A. Dependent on the phase connectivity (see Info tab) the value must be entered as phase value.
cos (phi)
()
Power factor of the load. Dependent on the phase connectivity (see Info tab) the value must be entered as phase value.
E
()
Total yearly energy consumption in MWh or kWh. Conversion into P with Velander-Coefficients: E = kvel1 ⋅ E + kvel 2 ⋅ E
Velander factor 1
()
Velander-Coefficient 1
Velander factor 2
()
Velander-Coefficient 2
Distance
()
Distance of the load in m or in % from the starting node of the line.
Domestic units
()
Number of domestic units (see below).
Total scaling factor for P
()
Indicates the total scaling factor for the active power of the line load. It is calculated by the product of the network and the zone scaling factor, the scaling factor of the line load and the calculated scaling factor. P: fep=fnp*fzp*fs*fc
() Total scaling factor for Q
Indicates the total scaling factor for the reactive power of the line load. It is calculated by the product of the network and the zone scaling factor, the scaling factor
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of the line load and the calculated scaling factor. Q: feq=fnq*fzq*fs*fc Scaling factor
()
Scaling factor of the line load for the active and reactive power. This factor will be multiplied by the network and the zone scaling factor as well as with the calculated scaling factor.
Scaled values
()
The scaled values for Poper, Qoper, Soper, Ioper and Cos(phi)oper are calculated with P and Q and the respective scaling factors: Poper= P* fep ; Qoper= Q* feq
Load Balancing
Calculated () scaling factor (P,Q)
Shows the calculated scaling factor after a load flow calculation with load balance if the option "Load balance - Set calculated values" in the Load flow Parameters is active. The factor can be modified manually after a load balancing calculation. It will be multiplied by the network and the zone scaling factor and by the scaling factor of the line load.
Remark: The predefined scaling factors for the network and zones may be modified in “Data - Operational Data” of the menu Edit (see chapter “Menu Options”).
Line Load - Info
The Info tab is described in “Element - Info” of chapter “Data Input Dialogs of Network Elements” on page 4-2.
Line Load - Reliability
The Reliability tab is described in “Element - Reliability” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
Line Load - User Data
The User Data tab is described in “Element - User Data” of chapter “Data Input Dialogs of Network Elements” on page 4-3.
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Mixed Load Power (Line Load)
The consumed power of a load consists of • a general load P and Q (input see above) and • a load due to the number of domestic units nDU. The active power PDU and the Cos(phi), which are assigned to one domestic unit, are entered in the load flow parameter mask. The power, which will be taken by the load flow is correspondingly: Pcal = P + nDU · PDU Qcal = Q + nDU · PDU · Sin(phi) / Cos(phi) The powers Pcal and Qcal are multiplied by the simultaneity factor. When calculating the load flow accordingly to the voltage drop method, an other power will be set for mixed load power (see chapter "Load Flow"). Assignment of the Loads to the Line Load Center
The line loads are assigned to a new node on the line. During load flow calculation this node will be generated automatically by the program in the load center of the line. The load center is calculated as follows:
∑ P ⋅l l
tot
= ∑ (Pl ⋅ ll )
ltot = ∑ (Pl ⋅ ll )
∑P
l
with Pl ll ltot
Active power of the line load Distance of the line load from the line’s starting node Distance of the line load center from the line’s starting node
The new node, which is generated in a distance of ltot from the line’s starting node, gets an arbitrary name. The sum of all loads of the line is assigned to this node. If the load center is closer than 7m from the line’s starting or ending node, no new node will be generated. Then the line loads are assigned to either the starting node or ending node. The position of the line load symbol has nothing to do with the load center. To the line load symbol no results are assigned.
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Description of the Model (Line Load)
See chapter "Load Flow".
Phasing of the line loads
The line loads have the same phasing connectivity as the line itself. A single phase line for example carries only single phase loads.
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User Defined Scaling Factors The user can define constant scaling factors and time-dependent scaling factors for day-times, week-days, moths and years. The factors may be defined only in the project or they can be saved to a library. There exist the following possibilities to enter in the user defined scaling factors editor: To define Scaling Factors and time-dependent characteristics to a library, while the project won’t be modified: • Menu Libraries – Scaling Factors To define Scaling Factors and time-dependent characteristics directly in the project, to export them to a library or to get them from a library: • Menu Edit – Data – Define Scaling Factors • Data Input Dialog of an element – tab Scaling Factors – Define Scaling Factors To calculate the Effective Scaling Factors for a certain element, the User Defined Scaling Factors are multiplied with the Predefined Scaling Factors for the network and zones. Predefined Scaling Factors may be modified in “Edit Data – Operational Data”. For more information about Predefined Scaling Factors see chapter “Menu Options”.
Scaling Factors
A list of all existing Scaling Factor types appears after having selected the tab “Scaling Factors” in the Scaling Factor Editor. For every type the user can define constant scaling factors and time-dependent scaling factors. Scaling Factor types may be added or removed. Types
Shows all existing Scaling Factors types. With “New”, a type can be added; with “Delete” a type may be removed.
Description
Description of the Scaling Factors type.
Constant factor for manual scaling
Constant scaling factor for P and Q.
Time-dependent The time-dependent factor is composed of a "Day by factor Hours" characteristic, a "Week by Days" characteristic, a "Year by Months" characteristic and a "Long Term by Years" characteristic (see below). By pressing the button “Select” the characteristic curves may be selected. NEPLAN User's Guide V5
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The time-dependent scaling factor is used only for the module "Load Flow with Load Profiles" and it is calculated as follows: Pfactor_t(t) = fd(t)*fw(t)*fy(t)*fl(t) Qfactor_t(t) = fd(t)*fw(t)*fy(t)*fl(t)
Day by Hours Characteristics
A list of all existing "Day by Hours" characteristics appears after having selected the respective tab in the Scaling Factor Editor. By clicking on a characteristic type, the corresponding curve will be displayed and its values may be modified. Characteristic types may be added or removed. Types
Shows all existing day characteristics types. With “New”, a type can be added; with “Delete” a type may be removed.
Description
Description of the day characteristic type.
Time-value-table Definition table. The program interpolates linearly between two points. In maximum 1440 time values may be entered; for every seconde a value. Time
Time (hour and minutes), editable directly in the table.
Factors
A P-factor and a Q-factor between 0 and 1 may be entered or edited directly in the table.
Insert 1 item
Inserts one time value after the marked line. If no line is selected, the additional value will be added at the end of the table.
Insert items
Inserts the indicated amount of time values after the marked line. If no line is selected, the additional time values will be added at the end of the table.
Remove
Removes the marked time values.
Same values for If this checkbox is active, the Q factors of the table won’t P and Q scaling be considered. Instead the Q factors will be the same as the P scaling factors.
Week by Days Characteristics
A list of all existing "Week by Days" characteristics appears after having selected the respective tab in the Scaling Factor Editor. By clicking on a characteristic type, the corresponding curve will be displayed and its values may be modified. Characteristic types may be added or removed. 4-152
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Types
Shows all existing week characteristics types. With “New”, a type can be added; with “Delete” a type may be removed.
Description
Description of the week characteristic type.
Day values
For all days, Monday to Sunday, a P and a Q factor between 0 and 1 may be entered. The values will be presented with bars in the graphic of the week characteristics.
Same values for If this checkbox is active, the Q factors of the table won’t P and Q scaling be considered. Instead the Q factors will be the same as the P scaling factors.
Year by Months Characteristics
A list of all existing "Year by Months" characteristics appears after having selected the respective tab in the Scaling Factor Editor. By clicking on a characteristic type, the corresponding curve will be displayed and its values may be modified. Characteristic types may be added or removed. Types
Shows all existing month characteristic types. With “New”, a type can be added; with “Delete” a type may be removed.
Description
Description of the month characteristic type.
Month values
For all months, January to December, a P and a Q factor between 0 and 1 may be entered. The values will be presented with bars in the graphic of the week characteristics.
Same values for If this checkbox is active, the Q factors of the table won’t P and Q scaling be considered. Instead the Q factors will be the same as the P scaling factors.
Long Term by Years Characteristics
A list of all existing "Long Term by Year" characteristics appears after having selected the respective tab in the Scaling Factor Editor. By clicking on a characteristic type, the corresponding curve will be displayed and its values may be modified. Characteristic types may be added or removed.
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Types
Shows all existing year characteristic types. With “New”, a type can be added; with “Delete” a type may be removed.
Description
Description of the year characteristic type.
Year values
For every year a P and a Q factor between 0 and 1 may be entered.
Year
Year (4 digits: e.g. 2004) for which a P and a Q factor should be defined.
P scaling
P-factor for the respective year.
Q-factor
Q-factor for the respective year.
Insert
Inserts a year value.
Remove
Removes a year value.
Same values for If this checkbox is active, the Q factors of the table won’t P and Q scaling be considered. Instead the Q factors will be the same as the P scaling factors.
Library Import / Export
If the user doesn’t modify the Scaling Factors directly in the Library Menu, the Library won’t be modified. In this case it exists the possibility to export or import Scaling Factors and Characteristics to and from the library. Actual project
The list contains all scaling factors and characteristic types defined in the project. They may be selected, unselected or deleted.
Selected library
The list contains all scaling factors and characteristic types defined in the active library. They may be selected, unselected or deleted.
Open Library
An existing library may be opened.
New Library
A new library may be created.
>> u1 :
y1 = K o + K a ⋅ ua + K b ⋅ (ub - ua ) + K c ⋅ (u1 - ub )
Impermissible: |Ka|,|Kb| or |Kc| smaller than 10-8 or larger than 108
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Gain - Tabularly non-linear Functional description:
A tabular function f(u) is used as the transfer function. Data are entered into the table in the TAB data block of the Dynamic Data file. The type of interpolation to be used (linear, cubic or Newtonian) is likewise specified there.
y1
u1
Fig. 4.56 Gain block - Tabularly non-linear
Transfer function
Initial value
y1 = K 0 ⋅ f(u )
u1 ;
Remark
Under the mentioned For strictly monotonously descending condition on the left, or ascending tabular functions, y1 can iterative initialization also be given as the initial value (right- is permissible.
1
to-left initialization).
Impermissible: |K0| smaller than 10-8 or larger than 108
Exponential Functional description: Taking the exponent of the input variable u1.
u1
K
f(u1)
y1
Fig. 4.57 Exponential block
Transfer function y1 = K 0 + K1 ⋅ eK
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2 ⋅u1
Initial value
Remark
u1 or y1 ; If (y1 – K0)/K1 < 10-8 :
Iterative initialization without limits permissible. NEPLAN User's Guide V5
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u1 = ln(108)/K2
Impermissible: |K1| or |K2| smaller than 10-8 For initialization with y1 = 0: K0 and K1 not the same sign Power Functional description: Taking the K’th power of the input variable u1. K
u1
y1
K
U1
Fig. 4.58 Power block
Transfer function
Initial value
Remark
y1 = u1K
u1 or y1
Iterative initialization permissible
Impermissible: |K| smaller than 10-4 or greater than 104
Absolute Functional description: Absolute value of input variable u1
u1
y1
Fig. 4.59 Absolute value block
Transfer function
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Remark
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y1 = u1
u1
Iterative initialization permissible
Limitation Functional description: Limiting the input variable u1 to a maximum or minimum value, which may also depend on another input variable. u2⋅ymax u2
K
u1 u3
y1 1
u3⋅ymin Fig. 4.60 Limitation
Transfer function
Initial value
y1 = Minimum(u1,u2·ymax) u1 or y1 y1 = Maximum(u1,u3·ymin)
Remark
Iterative initialization without limits permissible
Limitation: The limitation is of the "windup" type. If you want to deactivate the limitation function, you must set ymax and ymin to equal 0. u2 and u3 can be used to simulate dependent limit values. If the limit values concerned are constant, then you must specify blanks for u2 and/or u3.
Rate of change limitation Functional description: Limiting the change of input variable u1 to a maximum or minimum value, which may also depend on another input variable.
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Example:
u2⋅y’max u2
K
u1 u3
u1, y1
Input u1 Output y1
y1 1
Decline y’min Increase y’max
u3⋅y’min
t
Fig. 4.61 Rate of change limitation
Transfer function
Initial value
Remark
see the example given above.
u1 or y1
Iterative initialization without limits permissible
Limitation: The limitation is of the "windup" type. If you want to deactivate the limitation function, you must set ymax and ymin to equal 0. u2 and u3 can be used to simulate dependent limit values. If the limit values concerned are constant, then you must specify blanks for u2 and/or u3.
Dead band Functional description: Dead band with gain factor. u1
K
y1
umin umax
Fig. 4.62 Dead band
Transfer function
Initial value
Remark
u1 ≥ u max u min < u1 < u max u1 ≤ u min
u1
Iterative initialization not permissible
y1 = K 0 ⋅ u1 y1 = 0 y1 = K 0 ⋅ u1
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Impermissible: |K0| smaller than 10-8 or larger than 108 HV Gate
Functional description: The larger of the two input signals, u1 and u2, is switched through to the output. HV gate corresponding to [4].
u1
K
y1 f(u1,u2)
u2
Fig. 4.63 HV Gate
Transfer function
Initial value
Remark
if u1 ≥ u2 : if u1 < u2 :
u1 and u2 ⇔ always possible u1 and y ⇔ only if y > u1 u2 and y ⇔ only if y > u2
Iterative initialization not permissible
y1 = u1 y1 = u2
LV Gate
Functional description: The smaller of the two input signals, u1 and u2, is switched through to the output. LV gate corresponding to [4].
u1 u2
K
y1 f(u1,u2)
Fig. 4.64 LV Gate
Transfer function
Initial value
Remark
if u1 ≤ u2 : if u1 > u2 :
u1 and u2 ⇔ always possible u1 and y ⇔ only if y < u1 u2 and y ⇔ only if y < u2
Iterative initialization not permissible
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Coordinate transformation - Polar → Rectangular Functional description: Converting the variable u1 (magnitude) and the variable u2 (angle in [rad]) into a real and an imaginary part of a complex variable, and multiplying it by a complex constant K.
u1
y1
K
f(u1,u2)
u2
y2
Fig. 4.65 Coordinate transformation - Polar → Rectangular
Transfer function
Initial value
Remark
K = K1+j⋅K2 z1 = u1⋅cos(u2) z2 = u1⋅sin(u2) z = z1+j⋅z2 y = y1+j⋅y2 = K⋅z y1 = z1⋅K1-z2⋅K2 y2 = z1⋅K2+z2⋅K1
u1 and u2
Iterative initialization permissible
Coordinate transformation - Rectangular → Polar
Functional description: Multiplying the variable u1 (real part) and the variable u2 (imaginary part) by the complex constant K and converting the complex result into magnitude and angle (in [rad]).
u1 u2
y1
K
f(u1,u2)
y2
Fig. 4.66 Coordinate transformation - Rectangular → Polar NEPLAN User's Guide V5
4-211
Element Data Input and Models
Transfer function
Initial value
Remark
z1 = u1⋅K1-u2⋅K2 z2 = u1⋅K2+u2⋅K1
u1 and u2
Iterative initialization permissible
y1 =
z12 + z22
y 2 = arctan
z2 z1
Excitation - Per Unit Conversion Functional description: No function, kept for compatibility reasons.
u1
K
y1 1
Fig. 4.67 Excitation - Per Unit Conversion
Transfer function
Initial value
Remark
y1 = u1
u1 or y1
Iterative initialization permissible
Excitation - Saturated exciter machine Functional description: Exponential transfer function for simulating the feedback of saturable exciters (KE + SE ) used as per [4] and/or [5].
u1
4-212
K
f(u1)
y1
NEPLAN User's Guide V5
Element Data Input and Models
Fig. 4.68 Excitation - Saturated exciter machine
Transfer function
(
y 1 = K 0 + K 1 ⋅ eK
2
⋅u1
)⋅ u
1
Initial value
Remark
u1
Iterative initialization permissible
Impermissible: |K1| or |K2| smaller than 10-8 Remark: The constants are computed as follows from the parameters stated in [4] and/or [5]:
S4E 0.75 max K1 = 3 S E max
V K 0 = R max − S E max E FD max K2 =
4 E FD max
S ⋅ ln E max S E 0.75 max
Excitation - Static exciter Functional description: Static excitation as per IEC 34-16-1, 1991.
u1
Π
y1
f(x) u2
K0 ⋅ u 2 u1
Fig. 4.69 Excitation - Static exciter
Transfer function
Initial value
See block diagram above. The non- u1 and u2 linear function f(x) corresponds to NEPLAN User's Guide V5
Remark
Iterative initialization not permissible 4-213
Element Data Input and Models
the NLF 2 function block (rectifier regulation characteristic). Remark: The input and output variables correspond to the following electrical variables of static exciter devices: u1 = VE u2 = IFD y = EFD Excitation - Rectifier controller Functional description: Non-linear function corresponding to the "rectifier regulation characteristic" in [4].
u1
K
f(u1)
y1
Fig. 4.70 Excitation - Rectifier controller
Transfer function
Initial value
Remark
u1 ≤ 0 :y1 = 1 if u1 ≤ (√3)/4 : y1 = 1-(1/√3)⋅u1
u1 or y1
Iterative initialization permissible
if (√3)/4< u1 < 3/4 : y1 =
2 3/4 - u1
if u1 ≥ 3/4 : y1 = (√3)⋅(1-u1) if u1 ≥ 1 : y1 = 0
Excitation - Non-continuous controller Functional description: Non-linear function corresponding to Type DC3 in [4].
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Element Data Input and Models
u1 u2
K
y1 f(u1,u2)
Fig. 4.71 Excitation - Non-continuous controller
Transfer function
Initial value
Remark
if u2 > K0 : y1 = YMAX if |u2| ≤ K0 : y1 = u1 if u2 < -K0 : y1 = YMIN
u1 and u2
Iterative initialization not permissible
Static compensators - Firing angle Functional description: Non-linear function for simulating the output of thyristor controls plotted against the firing angle.
u1
K K0
y1
0
1,0
Fig. 4.72 Static compensators - Firing angle
Transfer function
Initial value
Remark
1 y1 = K 0 ⋅ u1 − ⋅ sin (π ⋅ u1 ) π
u1 or y1
Iterative initialization permissible
Impermissible: |K0| smaller than 10-8 or larger than 108
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Element Data Input and Models
Static compensators - Step function Functional description: Step function
u1
K
y1
Fig. 4.73 Static compensators - Step function
Transfer function
Initial value
Remark
u1 < 0 u1 > u max
u1
Iterative initialization not permissible
u1 ≥ (i − s) ⋅
u max n
y1 = 0 y1 = K y1 = K ⋅
i n
Note: n: i: s: 0: 0.5: 1: umax:
Number of intervals of the u-range Ongoing interval i = 1...n Position of step change 0≤s≤1 Step change on the right of the interval Step change in the middle of the interval Step change on the left of the interval Range for u1
Impermissible: umax or ymax smaller than +10-8 or larger than +108 The function is defined only for positive umax or ymax Remarks: For the initialization of u1 from a given y1 the step function is shifted parallel to the y-axis, such that the given y1 value exactly lies on a step.
Integrator Functional description:
Integrator. 4-216
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Element Data Input and Models
u2⋅yma u1
y1,0
u2
f(s)
u3
y1
u3⋅ymin Fig. 4.74 Integrator
Transfer function y1 =
K0 ⋅ u1 s
Initial value
Remark
y1, an initial value can be given Iterative initialization as input. permissible
Limitation: The limitation is of the "non-windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values. Time-delay block 1st-order Functional description: 1st-order time-delay block
u2⋅ymax u2
K
u1 u3
y1 f(s)
u3⋅ymin Fig. 4.75 Time-delay block 1st-order
Transfer function y1 =
K0 ⋅ u1 1 + sT N1
NEPLAN User's Guide V5
Initial value
Remark
u1 or y1
Iterative initialization without limits permissible
4-217
Element Data Input and Models
Limitation: The limitation is of the "non-windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values.
Derivative block 1st-order Functional description: 1st-order derivative block
u2⋅ymax u2
K
u1 u3
y1 f(s)
u3⋅ymin Fig. 4.76 Derivative block 1st-order
Transfer function y1 =
K 0 ⋅ sTD ⋅ u1 1 + sTD
Initial value
Remark
u1
Iterative initialization without limits permissible
Limitation: The limitation is of the "windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values. Remarks: Time constants smaller than 10-5 will automatically be taken as 10-5
PI controller Functional description: PI controller 4-218
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Element Data Input and Models
u2⋅ymax u2
K
u1 u3
y1 f(s)
u3⋅ymin Fig. 4.77 PI controller
Transfer function
y1 = K 0 ⋅
1 + sTZ ⋅ u1 1 + sTN
Initial value
Remark
u1 or y1
Iterative initialization without limits permissible
Limitation: The limitation is of the "non-windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values. Remarks: If the denominator time constant equals 0, then the Transfer function corresponds to the CONSTANT function block with limitation.
PID controller Functional description: PID controller
u2⋅ymax u2
K
u1 u3
y1 f(s)
u3⋅ymin
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Element Data Input and Models
Fig. 4.78 PID controller
Transfer function y1 = K 0 ⋅
Initial value
u1 or y1 (1+ sTZ1 ) ⋅ (1+ sTZ2 ) ⋅ u1 (1+ sTN1 ) ⋅ (1+ sTN2 )
Remark
Iterative initialization without limits permissible
Limitation: The limitation is of the "non-windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values. Remarks: Time constants |TN1|, |TN2|, |TZ1| or |TN1-TN2| smaller than 10-5 will automatically be taken as 10-5.
Rational transfer function 2nd-order Functional description: 2nd-order rational transfer function
u2⋅ymax u2
K
u1 u3
y1 f(s)
u3⋅ymin Fig. 4.79 Rational transfer function 2nd-order
Transfer function
Initial value
u1 or y1 b o + b1 ⋅ s + b 2 ⋅ s 2 y1 = ⋅ u 1 a o + a1 ⋅ s + a 2 ⋅ s 2
Remark
Iterative initialization without limits permissible
Impermissible: 4-220
NEPLAN User's Guide V5
Element Data Input and Models
|a0|, |a2| or |b0| smaller than 10-8. Any value smaller than 10-8 will be taken internally as 10-8. Limitation: The limitation is of the "windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values. Rational transfer function 3rd-order Functional description: 3rd-order rational transfer function
u2⋅ymax u2
K
y1
u1 u3
f(s)
u3⋅ymin Fig. 4.80 Rational transfer function 3rd-order
Transfer function y1 =
Initial value Remark
u1 or y1 b o + b1 ⋅ s + b 2 ⋅ s 2 + b 3 ⋅ s 3 ⋅ u 1 a o + a1 ⋅ s + a 2 ⋅ s 2 + a 3 ⋅ s3
Iterative initialization without limits permissible
Impermissible: |a0|, |a3| or |b0| smaller than 10-8 Any value smaller than 10-8 will be taken internally as 10-8. Limitation: The limitation is of the "windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values.
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Element Data Input and Models
Rational transfer function 4th-order Functional description: 4th-order rational transfer function
u2⋅ymax u2
K
u1 u3
y1 f(s)
u3⋅ymin Fig. 4.81 Rational transfer function 4th-order
Transfer function
Initial value Remark
u1 or y1 b o + b1 ⋅ s + b 2 ⋅ s 2 + b 3 ⋅ s 3 + b 4 ⋅ s 4 y1 = ⋅ u 1 a o + a1 ⋅ s + a 2 ⋅ s 2 + a 3 ⋅ s 3 + a 4 ⋅ s 4
Iterative initialization without limits permissible
Impermissible: |a0|, |a4| or |b0| smaller than 10-8 Any value smaller than 10-8 will be taken internally as 10-8. Limitation: The limitation is of the "windup" type. If you want to deactivate the limitation function, you must set ymax and ymin equal to 0. u2 and u3 can be used to simulate dependent limit values.
Binary - Not Functional description: Negation of a binary variable.
u1
y1
Fig. 4.82 Binary – Not
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Element Data Input and Models
Transfer function
Initial value
Remark
y1 = NOT (u1)
u1 or y1
Iterative initialization not permissible
Remark: A variable or a controller signal is logically TRUE if its numerical value is larger than or equals 0.5.
Binary - And
Functional description: "AND" function of two binary variables.
u1
K
y1 f(u1,u2)
u2
Fig. 4.83 Binary - And
Transfer function
Initial value
if u1 and u2: y1 = TRUE u1 and u2 otherwise: y1 = FALSE
Remark
Iterative initialization not permissible
Remark: A variable or a controller signal is logically TRUE if its numerical value is larger than or equals 0.5. Binary - Or Functional description: "OR" function of two binary variables.
u1 u2
K
y1 f(u1,u2)
Fig. 4.84 Binary - Or NEPLAN User's Guide V5
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Element Data Input and Models
Transfer function
if u1 or u2: otherwise:
Initial value
y1 = TRUE u1 and u2 y1 = FALSE
Remark
Iterative initialization not permissible
Remark: A variable or a controller signal is logically TRUE if its numerical value is larger or equal to 0.5. Binary - Switch Functional description: Depending on the state of u1, the input signal u2 or u3 is switched through to the output.
u2
K
y1
u1 u3 Fig. 4.85 Binary - Switch
Transfer function
Initial value
Remark
u1 = TRUE y1 = u2 u1 = FALSE y1 = u3
u1, u2 and u3
Iterative initialization not permissible
Remark: A variable or a controller signal is logically TRUE if its numerical value is larger or equal to 0.5.
Rational function 2nd-order Functional description: Rational Function of second order.
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Element Data Input and Models
u1
A + B ⋅ u1 + C ⋅ u12 D + E ⋅ u1 + F ⋅ u12
y1
Fig. 4.86 Rational function 2nd-order
Transfer function
Initial value
Remark
A + B ⋅ u1 + C ⋅ u12 y1 = D + E ⋅ u1 + F ⋅ u12
u1, y1
Iterative initialization permissible.
Impermissible: |D| and |E| and |F| < 10-8
Remarks concerning the initialization For a given initial value y1 and |C| or |F| > 10-8 printout of the roots is displayed (see also Error 1). For the calculation of u1 positive root is used.
During initialization following error messages may be recorded: a) Given initial value u1 or iterative initialization: Error 0 : D + E ⋅ u 1 + F ⋅ u 12 < 10 −8
Initialization continues with denominator = 10-8 . b) Given initial value y1, if |C| or |F| ≥ 10-8: Error 1 : ( B − E ⋅ y 1 ) 2 − 4 ⋅ (C − F ⋅ y 1 ) ⋅ ( A − D ⋅ y 1 ) < 0 (Printout of roots) Error 2 : C − F ⋅ y1 < 10 −8
c) Given initial value y1, if |C| and |F| < 10-8: Error 3 : B − E ⋅ y 1 < 10 −8 d) Given initial value y1, if |B| and |C| and |E| and |F| < 10-8: Error 4 : A < 10 −8
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Element Data Input and Models
IF-THEN-ELSE Switch Functional description:
Depending on the value of u1 related to a constant K, u2 or u3 is switched to the output. The operator between u1 and K is selectable. u2 y1
u1 u3
Fig. 4.87 IF-THEN-ELSE Switch
Transfer function
Initial value
u1 If u1 # K is true : y1 = u2 Otherwise : y1 = u3 The operator # can be selected as .
4-226
Remark
Iterative initialization not permissible.
NEPLAN User's Guide V5
Load Flow
Load Flow Calculation Parameters (LF) The calculation parameters are entered with the help of a "Parameters" dialog. It consists of the three tabs, Parameter, References and Area/Zone Control, which are explained here. Parameter Calculation method
The Load flow can be calculated according to one of the following methods (see “Calculation methods and their application” on page 5-14): • Extended Newton-Raphson method • Current iteration method • Newton-Raphson method • Voltage drop (only for radial networks !)
Calculation with Distributed slack
Indicates, whether the load flow should be calculated with distributed slack or not (see "Calculation with Distributed Slack" on page 5-19).
Area control
Indicates, whether the load flow should be calculated with area control or not (see "Area/Zone Control (LF)" on page 520).
Wheeling
Option for Area control. Option deactivated: The power exchange (calculated from the transactions) takes place only over the elements connecting the two network groups (tie elements). Option activated: The power exchange defined for each transaction, can involve other network groups, not participating in the transaction. Wheeling is always allowed when calculating with the Newton Raphson or current iteration method.
Load balance
If checked, the load flow will be calculated with load balance. The loads will be adjusted (see "Calculation with Load Balance" on page 5-19).
NEPLAN User's Guide V5
5-1
Load Flow
Set calculated values
Option for Load balance. If checked, the load will be set after a successful load flow calculation with load balance to the calculated value. This is not valid for Load flow with Load profile.
Transformer phase shifting
Indicates, whether the phase shifting of transformers should be considered or not. The phase shifting is always considered for asymmetrical load flow. This parameter is not yet valid for Extended Newton Raphson Method.
Autom. transformer regulation
If checked, the taps of regulated transformers will be automatically adjusted to obtain a node voltage Uset in %. If not checked no transformers will be regulated.
Set taps to calcu- If checked, the actual transformer taps are set to the calculated values lated taps (Tap act = Tap cal). Asymmetrical network
Indicates, whether the load flow will be calculated with symmetrical or asymmetrical network structure. If calculating symmetrical load flow, the asymmetrical elements are not considered.
Control generator Indicates, whether the limits of synchronous machines are limits controlled during LF calculation. If box is not checked, the node type will not be changed during NR iteration (see "Change of node type with Newton-Raphson method"). MW loss sensitiv- If the checkbox is checked, the change of the network active power losses in respect to a change of active power in the ity: MW generarespective node, will be calculated: dSPn=∆Ploss/∆Pn tion at all nodes MW loss sensitiv- If the checkbox is checked, the change of the network active power losses in respect to a change of reactive power in the ity: MVAR genrespective node, will be calculated: dSQn=∆Ploss/∆Qn eration at all nodes Operational frequency
Operating frequency in Hz. This value is considered, when a load flow at a different frequency than the nominal system frequency must be performed. The static of the generators are taken into account (see "Synchronous Machine Data" in chapter "Element Data Input and Models").
Result file "…"
It’s possible to write a result file (*.rlf) right after the calculation. Select the file destination and the file name. This result file can be read by external programs, such as Excel and the results can be evaluated in an arbitrary way.
Write after calculation
Check this option to write the result file right after the calculation.
Format 4.0
The File can be written in the old Format 4.x (checked) or in
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NEPLAN User's Guide V5
Load Flow
a new Format for V5.x (not checked). Iteration data Convergence mismatch:
Convergence criteria for the iteration (see section "Theory of Load Flow Calculation" on page 5-10). Recommended values: 1.0E-3 .. 1.0E-5.
Max. number of iterations:
Maximum number of iterations. If the load flow does not converge, the iteration will stop when this number is exceeded.
Check convergence
Use of step control, so that the mismatch decreases in every iteration.
Read initialization If this box is checked, a previous created file (extension: *.ilf) file with the node voltages and transformer taps will be read. In this case the load flow will not be started with U=1.0pu (flat start). The name of the file to be read can be entered. Write initialization If this box is checked, a file (extension: *.ilf) with the node file voltages and the calculated transformer taps will be created. The name of the file can be entered. Current iteration / asymmetrical networks Acceleration factor:
Factor for handling the PV-nodes for current iteration method. The larger the factor, the faster the load flow will converge. The load flow may diverge if a too large value is entered. If there are no PV-nodes, this factor is irrelevant. Possible values: 0.05 .. 0.4. This factor is also used for asymmetrical load flow with current iteration method as well as for Newton-Raphson method. If the network structure is symmetrical or nearly symmetrical the factor can be set to a value near 1.0. If the network structure is highly asymmetrical it is recommended to take a value of 0.25. or less.
Reference values for loading check Minimum values Maximum values
The user can select, whether the minimal or the maximum rated values of the lines and transformers has to be taken to calculate the loading of these elements.
Switches, circuit breakers and couplers Reduce
Check this box to reduce switches, circuit breakers and couplers. The calculation will be faster and the possibility of convergence is higher, but no results for these elements will be calculated. If the box is not checked, for calculation, these elements are represented by the impedances entered in the Data Input Dialogs. This option is not available for the calculation method "Extended Newton Rapson". In this case these elements are
NEPLAN User's Guide V5
5-3
Load Flow
modeled without any impedance, so they can't provoke convergence problems. Domestic units P
Active power in kW of one domestic unit. This value is used for loads and line loads.
Cos(phi)
Cos(phi) of domestic unit. This value is used for loads and line loads.
Kn
Interlacing factor for infinite number of domestic units. This value is used for loads and line loads.
References Reference for Elements %:
Maximum loading of element in the system (only relevant for evaluation option). Overloaded elements are presented in the Summary of the load flow results.
Minimum Voltage Minimum value for node voltage with respect to nominal system voltage (only relevant for evaluations). In the table, the reference voltages can be entered individually for each node. Voltages out of limits are presented in the Summary of the load flow results. Maximum Voltage Maximum value for node voltage with respect to nominal system voltage (only relevant for evaluations). In the table, the reference voltages can be entered individually for each node. Voltages out of limits are presented in the Summary of the load flow results. Assign voltages: All
By pressing this button, the default minimum and maximum voltages will be assigned to every node.
Assign voltages: Voltage level
By pressing this button, the voltage level can be chosen, to which the default minimum and maximum voltages will be assigned.
Area/ Zone Control Control type
5-4
The user can chose between the following control types: - Area control - Zone control - Area and zone control
NEPLAN User's Guide V5
Load Flow
Depending on the control type, only the respective power interchanges of the table, will be considered for the calculation. From area To area
For area control, it has to be defined from which to which area the power has to flow. By pressing the "Insert" button, this transaction will be added to the table, where the values may be edited.
From zone To zone
For zone control, it has to be defined from which to which zone the power has to flow. By pressing the "Insert" button, this transaction will be added to the table, where the values may be edited.
Losses taken over by Slack
During Area/Zone Control calculations, losses in the network are taken over by the area or zone which includes the only slack node in the network. As every node is assigned to an area and a zone at the same time, for the control type "Area and zone control", it has to be defined if the area or the zone which includes the slack node, has to take over the network losses.
Table entries Name
Name of the transaction.
Active
Check the box to activate this transaction.
Type
Type of transaction, Area-Area or Zone-Zone.
From
MW-power sending area or zone.
To
MW-power receiving area or zone.
Psch
MW-power to be transmitted.
Tolerance
Only for optimal power flow. Maximum deviation from Psch (Psch –Tolerance = Io L or Ik"(L2) >= Io L or Ik"(L3) >= Io L.
Io S (*Ir):
Total current limit related to the current transformer’s primary current Ir. Value for line-earth faults. Starting condition: (Ik"(L1) + Ik"(L2) + Ik"(L3)) >= Io S.
The entered data are displayed in a U-I diagram.
Under Impedance The data are entered according to fig. 10.1:
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NEPLAN User's Guide V5
Distance Protection
U / Ur
U limit max U limit min Starting area I / Ir I limit
Io1
Fig. 10.1a Phase-independent under impedance starter
U / Ur
U limit min = U limit max Starting area
I / Ir I limit
Io 1
Io 2
Fig. 10.1b Phase-dependent under impedance starter
The input data are: I limit (*Ir):
Phase current limit related to the current transformer’s primary current Ir. Value for line-line and line-earth faults.
Io 1 (*Ir):
1. overcurrent limit in a phase related to the current transformer’s primary current Ir. Value for line-line and line-earth faults.
Io 2 (*Ir):
2. overcurrent limit in a phase related to the current transformer’s primary current Ir. Value for line-line and line-earth faults.
U limit min (*Ur):
Minimum voltage limit between line-earth or line-line (see below) related to the voltage transformer’s primary voltage Ur.
U limit max
Maximum voltage limit between line-earth or line-line (see below)
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Distance Protection
(*Ur):
related to the voltage transformer’s primary voltage Ur.
Phi min, Phi max:
Minimum and maximum phase angle for a phase-dependent starter in degree. In case of a short circuit and if the angle between phase current and phase voltage is between Phi min and Phi max, the current limit Io 2 is considered instead of Io 1.
I sum (*Ir):
Total current limit related to the current transformer’s primary current Ir. Value for line-earth faults. Starting condition: (Ik"(L1) + Ik"(L2) + Ik"(L3)) >= I sum.
UL-L, UL-E Dependent on the activated check box, the program takes the lineline or the line-earth voltage to compare with the limit values "U limit min" and "U limit max". The value "Io 2" should not be entered or set to zero for phase-independent under impedance starters. The input of "Phi min" and "Phi max" is then unimportant. The value "Io 2" must be defined for a phase-dependent under impedance starter. The values "U limit min" and "U limit max" must be set equal.
Starter Characteristic L-L With this option the user can enter • a polygon or • a circle as starter characteristic for line-line faults in the R/X-diagram. The values can be entered with the mouse or in a mask. If the measured impedance is inside the polygon or inside the circle the relay will start. Dependent on the relay type (userdefined or predefined relay) and the input mode (mouse or mask) the following menu options are available: Setting Parameters This menu option is only available when working with predefined relay type. The setting parameters of the predefined relay are shown in section "Tripping" on page 10-10. Limit Current Additionally to the starter characteristic the user can enter a limit current I limit. If a value is entered, the relay starts only when the following conditions are valid • Ik"(L1, L2, L3) >= I limit and • impedance Z inside polygon respectively circle.
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Distance Protection
The value I limit must be entered related to the current transformer’s primary current Ir. Entering the settings with the mouse Input After having selected the option a polygon or a circle (dependent on the activated option in the menu) can be entered. A polygon can be entered with mouse clicks in the R/X-diagram. The input terminates after a double click. The program connects the first and the last entered point to a closed polygon. During the input the mouse position is given: mouse positition:
X / Ohm
Rp = Xp =
Beta Xp
P
Phi = Beta = Phi Rp
R / Ohm Fig. 10.2 Mouse position
In addition to the mouse position (R, X, and Phi) the angle Beta is also given. The angle Beta represents the angle between the last entered section and the section, which would be built with the next entered point. In the mask for dimensions the drawing area (minimum and maximum values in vertical and horizontal direction), the grid, etc. can be defined. The mouse position will also be displayed in the Z/Tand X/T-diagram. A circle will be defined with the input of a center (mouse click). With dragged mouse the radius can be entered. Delete, Undo After having selected this option the characteristic can be deleted. Option Undo undeletes the last deletion.
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Distance Protection
Entering the settings with the mask With menu option "Starter - Characteristic - Mask" the mask for entering the starter-characteristics appears. This mask appears also, when selecting the menu option "Tripping - Characteristic - Mask". The following input is possible: Characteristic for Starter / Tripping Dependent on this input a starter or a tripping characteristic is entered. Displayed Stage The stage, which characteristic is entered or displayed, must be defined. For starter this input is meaningless. Fault Type Gives the fault type the input values are for (L-L: line-line, L-E: line-earth faults). Characteristic Type The user has to define the characteristic type (circle or polygon). Dependent on the activated radio button different input fields are available. A circle is defined by a center and the radius. A polygon is defined by the input of a sequence of x,ypoints. The polygon can be changed with the push buttons "Insert" and "Delete". The polygon points are displayed in a list. The first point must be different than the last point. The polygon will be closed by the program itself.
Earth Faults Detection This starter type is only for earth faults. The input values are: Earth current IE(*Ir)
Earth current related to the current transformer’s primary current Ir. Starting condition: (Ik"(L1) + Ik"(L2) + Ik"(L3)) >= IE.
Earth voltage UE(*Ir)
Earth voltage (displacement voltage) related to the voltage transformer’s primary voltage Ur. Starting condition: (Uf(L1) + Uf(L2) + Uf(L3)) >= UE. Uf: Fault voltage line-earth.
If there is no earth faults detection, no values may be entered here. The earth faults detection works additionally to other starter systems.
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Starter Characteristic L-E With this option the user can enter • a polygon or • a circle as starter characteristic for line-earth faults in the R/X-diagram. The values can be entered with the mouse or in a mask. If the measured impedance will be inside the polygon or inside the circle the relay will start. The menu options are the same as in section "Starter Characteristic L-L" on page 10-6.
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Distance Protection
Tripping This menu option is available, when the option "View - Tripping" is activated. The tripping can be entered for user defined relay • with impedance values (settings) or • as a characteristic (polygon or circle) for line-line or line-earth faults and • for predefined relay directly with its setting parameters The kind of input can be chosen under the menu option "Tripping". Additionally an overcurrent-time function with 2 stages as back-up protection can be defined. The tripping stages can be automatically set by the program. The characteristics can be displayed in the R/X-, Z/T- or X/T-diagram (see "RelaySpecific Parameters" on page 10-26).
Impedance Stages for User Defined Relay The setting values can be entered as primary or secondary values (see "RelaySpecific Parameters" on page 10-26). The transformer ratio and the impedance of the protected line or the impedance to the next relay node are displayed. The input values are: Stage 1, 2, 3, 4:
Threshold impedance or reactance value of 1., 2., 3. and 4. Stage in Ohm per phase. The value can be entered in per cent related to the line impedance or impedance to the next relay node/station. If the relay has only 3 stages, the value for the 4. stage may not be entered.
Transition stage
Threshold impedance or reactance value of the transition stage in Ohm. The value can also be entered in per cent related to the line impedance.
Backward stage
Threshold impedance or reactance value of the backward stage in Ohm. The value can be entered in per cent related to the line impedance. The backward stage shows always in the opposite direction of the 1. stage.
The values are for line-line and line-earth faults. After quitting the mask the settings are shown in the R/X-, Z/T- or X/T-diagram.
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Tripping Characteristic L-L With this option the user can enter • a polygon or • a circle as tripping characteristic for line-line faults in the R/X-diagram. The values can be entered with the mouse or in a mask. The input can be done for 4 stages, 1 transition stage and 1 backward stage in the same way as for the input of the starter characteristics (see "Tripping Characteristic L-E" on page 10-11). The only difference is the deletion of a stage. After having selected "Delete" the characteristic, which has to be deleted, can be clicked. Undo undeletes the last deleted characteristic. In the Z/T and X/T-diagram no characteristics can be entered.
Tripping Characteristic L-E With this option the user can enter • a polygon or • a circle as tripping characteristic for line-earth faults in the R/X-diagram. The values can be entered with the mouse or in a mask. The input can also be done for 4 stages, 1 transition stage and 1 backward stage (see "Tripping Characteristic L-L" on page 10-11).
Setting Parameters for Predefined Relays The following relay types are predefined • ABB REL316 • Siemens 7SA511/7SA513 • AEG PD551/PD531 and SD36 The input mask will appear when selecting "Characteristic L-L faults" or "Characteristic L-E faults" in the "Starter" or "Tripping" menu. The parameters for starting and tripping can be entered in the mask. The documentation and the automatic setting of the relay can be done directly in the mask. For automatic setting the fault type should be set to asymmetrical fault in the global parameter mask. In this case the impedances of the zero sequence are also calculated.
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Distance Protection
If there is a overcurrent or under impedance with U/I-characteristic starter function the input has to be done according to the section above (see "Starter" on page 10-4). The setting parameters are explained in the corresponding manual.
ABB REL316 Starter characteristic: X XA
RLoad
R
RB AngleLoad
RA
-RLoad
XB
Tripping characteristic (only for 1st stage) X X 7°
27°
R
RR
-X / 8 -RR / 2
27°
RRE
-RRE / 2
For each stage the k0-factor has to be entered (amount and angle): k0 = (Zst(0) - Zst(1)) / (3*Zst(1))
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Siemens 7SA511, 7SA513 Starter characteristic: X X+A
RAE
RA1
RA2 RA1
PHIA
R
RA2 RAE
X-A
Tripping characteristic (only for 1st stage) X X1
R1 RE1
R1
NEPLAN User's Guide V5
RE1
R
45°
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Distance Protection
AEG PD531, PD551, SD36 Starter characteristic (only for PD551): X
110°
Xv
Zv
R Beta
Rv L-E Rv L-L
Zr
70°
Tripping characteristic polygon (only for 1st stage) X X
-135°
-RL-E
R
Alpha RL-L
-RL-L
RL-E
-X
Tripping characteristic circle with or without arc compensation (only for 1st stage)
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X Delta
-135°
Arc compensation
Alpha Phi
R
The function to get the arc compensation circle is:
Delta is in the range -45° < phi < alpha: delta = alpha - phi and in the range 135° < phi < (alpha + 180°): delta = alpha - phi + 180° For the overreach stage the factor ku for L-L and L-E faults must be entered.
Back-up Protection The distance protection relay can also be defined as an overcurrent relay. The input values are: 1. stage I (*Ir)
Current setting value of 1. stage related to the current transformer’s primary current Ir.
1. stage t
Tripping time of 1. stage in seconds.
2. stage I (*Ir)
Current setting value of 2. stage related to the current transformer’s primary current Ir.
2. stage t
Tripping time of 2. stage in seconds.
Earth current Ie (*Ir) Current setting value for line-earth faults related to the current transformer’s primary current Ir. Tripping condition (Ik"(L1) + Ik"(L2) + Ik"(L3)) >= Ie. t (earth current)
NEPLAN User's Guide V5
Tripping time for line-earth faults in seconds.
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Distance Protection
When evaluating the relay settings and if the relay has not been started by the distance protection relay, the values of the back-up protection are checked (see Relay evaluation). If there is no overcurrent functionality in the relay no values have to be entered here.
Automatic Impedance Setting The threshold impedance values or the characteristics of the stages 1 to 4 are automatically calculated by the program with the help of the automatic generated tripping schedules. The program generates all possible schedules, that the relay would see in forward and backward direction independent of the network type (unmeshed or meshed). The generated schedules can be changed by the user. Deleting and inserting nodes, he can build up his own schedules (see menu option "Tripping schedule - Edit"). Starting from the correct tripping schedules (network impedances) the program will automatically set the threshold impedance values or the characteristics. The user has to decide by itself, which tripping schedules have to be taken. Not important schedules must changed or deleted! The arbitrary number of schedules are reduced to a single schedule with the smallest impedances. For the setting, only the relay nodes are considered.
Relay location A R R Generated schedules
R
1.
R
2.
3.
Stage Resulting schedule
B
C
D Z / Ohm
Fig. 10.3 Getting the minimum impedance path in meshed networks
With the minimum impedance path the relay in location R will be set. The setting of the stages are made according to the following rules:
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1. stage: RRI = p1 ⋅ RAB 2. stage: RRII = p2 ⋅ (RAB + p1 ⋅ RBC) 3. stage: RRIII = p3 ⋅ (RAB + p2 ⋅ (RBC + p1 ⋅ RCD) 1. stage: XRI = p1 ⋅ XAB 2. stage: XRII = p2 ⋅ (XAB + p1 ⋅ XBC) 3. stage: XRIII = p3 ⋅ (XAB + p2 ⋅ (XBC + p1 ⋅ XCD) with: RAB, XAB RBC, XBC RCD, XCD RR, XR p1, p2, p3
Impedance between station A and B Impedance between station B and C Impedance between station C and D Stages 1 to 3 of the relay R Parameter for setting the stages (p = 0.85 .. 0.9).
The parameters p can be entered in the global calculation parameters. If only 3 stages should be automatically set, the parameter p4 for the 4. stage should not be entered. The same is valid for the overreach stage. The backward stage will not be set. The minimal impedance path can be displayed in the R/X-diagram with menu option "View-Minimum impedance path". In the documentation of a relay these impedance values are also shown (see "Relay Documentation" on page 10-30). Dependent on the activated menu option in "Tripping" the calculated setting values are the threshold impedance values or the characteristics. The characteristics can be polygons or circles. The type of characteristic can be entered in "Tripping - Characteristic". The points of the polygon (rectangle with 1 point in the origin 0;0) are calculated with the help of the line impedance. With ZR as calculated impedance, the polygon points in the R/X-diagram are calculated as follows: P1 = 0.0, 0.0 (R, X) P2 = 0.0, XR P3 = RR, XR P4 = RR, 0.0 The calculated impedance values are corrected with the arc resistance and the resistance for tower footing path. These values can be entered in the relay specific parameters.
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Distance Protection
Correction for line-line faults: RR = RR + RfL-L / 2 Correction for line-earth faults: RR = RR + RfL-E + RM with: RfL-L RfL-E RM
Arc resistance for line - line faults (see "Relay-Specific Parameters" on page 10-26) Arc resistance for line - earth faults (see "Relay-Specific Parameters" on page 10-26) Tower resistance for tower footing earth path (see "Relay-Specific Parameters" on page 10-26)
The calculated setting values are rounded to the snap entered in the mask for dimensions.
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Tripping Time The user can enter the tripping time of each stage.
Input The input values are: Stage 1, 2, 3, 4:
Tripping time of 1., 2., 3., 4. stage in seconds for lineline faults and line-earth faults.
Measuring direction:
Measuring direction of the stages 1 to 4 and of the end times. The check boxes are for: pos: positive measuring direction neg: negative measuring direction block: corresponding stage is blocked If a stage is bi-directional then both checkboxes ("pos" and "neg") must be activated.
Backward stage:
Tripping time of backward stage in seconds.
Directional end time:
Directional end time of relay in seconds.
Bi-directional end time:
Bi-directional end time of relay in seconds. Is only valid, if no value for directional end time is entered.
Automatic Time Setting After having selected this option the tripping times are calculated by the program. The tripping values are taken from the default values given in the global calculation parameters. If a node in the tripping schedule is a distribution pole with at least one out leading branch, which is protected by an overcurrent-time relay or fuse, then the tripping time will be corrected. The tripping time of the overcurrenttime relay (fuse) in the out leading branch can be entered in the node mask, input field "t dp" (see "Node Data" in chapter "Element Data Input and Models"). The fastest tripping time of the distance protection relay is set in order to have a tolerance time between the tripping time of the overcurrent relay (fuse) and the fastest tripping time of the distance protection relay. Nodes without distance protection relay are also considered. The tolerance time can be entered in the global calculation parameters.
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Distance Protection
View With this option the user can decide, if • the starter characteristic • the tripping characteristics • the tripping schedules in forward and/or backward direction or • the network impedances (impedance path) have to be displayed in the relay window. Additionally the dimensions can also be entered.
Starter The overcurrent starting values, the under impedance starting values or the characteristic is shown in the U/I-diagram respectively R/X-diagram.
Tripping The tripping characteristics are displayed in the R/X-, Z/T- or X/T-diagram, dependent on the input in the relay-specific parameters. The input of characteristics can only be done in the R/X-diagram. The calculation of the impedance values from the R/X- to Z/T- or X/T-diagram is done with the help of the complex line impedance. The crossing points of the line impedance and the characteristics (polygon or circle) are taken in the Z/T- or X/T-diagram. The distance of these crossing points to the origin (0,0), represents the impedance, which is shown in the Z/T-diagram:
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X/Ohm Line P2
1. Stage P3 Phi L
P1
P4
R/Ohm
t/s
1. Stage
Z/Ohm
Fig. 10.4 Calculation of the impedance values from the R/X- to the Z/T-diagram
If working with the X/T-diagram, only the reactance will be taken instead of the impedance.
Tripping Schedule After having selected this option a list of tripping schedules is displayed. These are automatically generated by the program. It is advisable to build up the tripping schedules with "Tripping Schedules - Build-up" and to look at these with "Tripping Schedules - Edit". The distance of the nodes from the relay location, which should be considered in the schedules, can be entered in the global parameters, input fields "Fault distance positive direction" and "Fault distance negative direction". A tripping schedule can be selected when double clicking a schedule or pressing "Select" in the list. Clicking the push button "D.backward" the tripping schedules in backward direction (negative impedances) are displayed. It is possible to display one schedule in forward direction and one in negative direction. The schedules must be selected one by one with this option. Pressing "Close" no schedule will be displayed in the corresponding direction. The time step characteristics are always displayed in the Z/T- or X/T-diagram. Additionally to the time step characteristics of the relays in the tripping schedule, the node impedances are displayed (vertical lines). The characteristics of the current relay are in the same color as the node impedances, which are seen by the relay. The vertical lines are dashed. The characteristics of the other relays are drawn in other colors. If a relay see an already drawn node with a different impedNEPLAN User's Guide V5
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Distance Protection
ance, the node (vertical line) will be drawn again with the same color as the relay characteristics. This can happen in meshed networks or when there are one or several feeders in that part of the network, which is represented by the schedule.
Network Impedances (Impedance Path) This option is to display in the R/X-, Z/T- or X/T-diagram all impedances (dependent on the fault distance!), which are seen by the relay, in case of a short circuit in the nodes of the tripping schedules. The voltages and currents seen from the relay are also displayed in the U/I-diagram. The user can select the following options: • Selection impedance path. The user can select an arbitrary impedance path (tripping schedule) • Display impedance path. If checked, the impedance path is displayed. • All impedances. All impedance paths are displayed. • Only relay nodes. If checked, only the impedances of the relay nodes are displayed • Minimal impedance path. If check the minimal impedance path is shown (see "Automatic Impedance Setting" on page 10-16) It is also possible to select only one schedule in positive and/or one in negative direction. In this case only the nodes of the selected schedule are displayed.
Dimensions For the representation of the starter and tripping characteristics the following values can be entered: Xmin:
Minimum value for the x-axis resp. horizontal direction. It could be for a current value I/Ir or an impedance or reactance value in Ohm.
Xmax:
Maximum value for the x-axis resp. horizontal direction. It could be for a current value I/Ir or an impedance or reactance value in Ohm.
Ymin:
Minimum value for y-axis resp. vertical direction. It could be for a voltage value U/Ur, an impedance or reactance value in Ohm or a time value in seconds.
Ymax:
Maximum value for y-axis resp. vertical direction. It could be for a voltage value U/Ur, an impedance or reactance value in Ohm or a time value in seconds.
Scaling: Scaling of x- and y-axis. Grid:
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Mouse grid for the input of characteristics in the R/X-diagram.
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Distance Protection
The quantities to be displayed in the x- and y-axis could be entered in the mask for relay-specific parameters. For the representation of the tripping schedules the following values can be entered: Zmin:
Minimum impedance value in Ohm for x-axis resp. horizontal direction.
Zmax:
Maximum impedance value in Ohm for x-axis resp. horizontal direction.
Tmax:
Maximum time value in seconds for y-axis resp. vertical direction.
Z scaling:
Scaling of x- respectively z-axis.
t scaling:
Scaling of y- respectively t-axis.
Number of char.:
The number of characters for relay, node and element description can be entered. This input is important, when the schedule is dense.
Number of pages: The tripping schedule can be displayed and plotted on different pages. The number of pages can be entered here. Scrolling forward and backward can be done with the menu options "Tripping schedule scroll".
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Distance Protection
Parameter (DP) With this menu option the global and the relay-specific parameters can be defined.
Global Parameter (DP) The mask for global parameters can also be called with "Calculation - Distance Protection - Parameter" in the main menu. The calculation parameters are: Project descr:
The project description is only displayed. It can not be changed. See menu option "Project-Info" in chapter "Menu Options".
Variant:
Description of the variant.
Kind of fault:
Type of fault at faulted nodes. Possible faults are: * 3-phase SC: 3-phase short circuit. * 1-phase GND: 1-phase to ground short circuit. * 2-phase SC: 2-phase short circuit. * 2-phase GND: 2-phase to ground short circuit. This input influence the calculation of the impedances, the relay documentation as well as the relay settings (line-line or line-earth).
Calc.method:
Following calculation methods are possible: * Superpos. w.out LF: The fault current Ik", the impedances and the voltages are calculated according to superposition method without prefault voltages from the Load flow. The EMF are 1.1*Un. * Superpos. with LF: The fault current Ik", the impedances and the voltages are calculated according to superposition method with prefault voltages from the Load flow. A Load flow calculation must have been performed, before setting the DP-relays (Short circuit calculation).
F. distance forw.:
The fault distance is the distance of the nodes, which are considered when generating the tripping schedules, from the relay location in forward direction. The input is also valid for the evaluation of the relay settings.
F. distance backw.: The fault distance is the distance of the nodes, which are considered when generating the tripping schedules, from the relay location in backward direction. The input is also valid for the evaluation of the relay settings.
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Tolerance time:
Tolerance time in seconds is the time between the tripping time of a overcurrent-time relay or fuse (in an out leading branch) and the fastest tripping time of the DP-relay. This input is only for the automatic settings of the tripping times (see "Automatic Time Setting" on page 10-19).
ZfL-L(R,X):
Fault impedance (resistance and reactance) in Ohm for line-line faults. These values are only for the evaluation, not for automatic impedance setting.
ZfL-E(R,X):
Fault impedance (resistance and reactance) in Ohm for line-earth faults. These values are only for the evaluation, not for automatic impedance setting.
Text file:
Name of result text file (*.TXT-file). This file will be needed to list the results of the evaluation (see "Checking the Relay Settings" on page 10-33).
Result file:
Name of ASCII-file (*.RDS-file). This file can be read by external programs such as Excel for evaluation purposes. The generation of this file can be prevented. The description of the fields can be activated with checkbox "Description". They are the same as in section "Checking the relay settings".
Description:
The fields in the result file are described.
Phases:
Gives the phases (L1 or L123 or 120) of the results to be listed in the text file. For symmetrical faults only the results of phase L1 will be given.
Time / Impedance values:
For the automatic relay setting the default values can be entered here. Section Automatic impedance setting shows, how the relay stages are set in dependence on the here entered parameters (percentage values). If a stage should not be set automatically, the corresponding values must not be entered. It is not allowed to leave out one stage, that means e.g. to enter the values for stage 1 and 3 without entering the values for stage 2.
Tripping schedules:
The impedance values in the tripping schedules can be primary or secondary values. The input can be done here.
Header:
The header in the listing can be activated or deactivated.
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Distance Protection
Relay-Specific Parameters The parameters are: Relay type:
Type of relay. The same input can be done in the mask of section "Distance Relay Data" in chapter "Element Data Input and Models".
Description:
Relay description.
RfL-L
Arc resistance in Ohm for line-line faults in order to make an automatic setting of the impedance stages (see "Automatic Impedance Setting" on page 10-16).
RfL-E
Arc resistance in Ohm for line-earth faults in order to make an automatic setting of the impedance stages (see Automatic impedance setting).
Rm
Tower resistance in Ohm for tower footing earth path in order to make an automatic setting of the impedance stages (see "Automatic Impedance Setting" on page 10-16).
Impedance values:
The impedance values can be entered or displayed as primary or secondary values. The network impedances are also displayed according to this input.
Tripping characteristic:
Dependent on this input, the relay settings and the network impedances are displayed in the following diagrams: R/X: x-axis: resistance R in Ohm y-axis: reactance X in Ohm Z/T: x-axis: impedance Z in Ohm y-axis: tripping time in seconds X/T: x-axis: reactance X in Ohm y-axis: tripping time in seconds The input for Z/T and X/T is also valid for the representation of the tripping schedules.
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Tripping Schedules
Build-up This function generates automatically the tripping schedules for the selecting relay in dependence on the fault distance in positive and negative direction. The fault distances are entered in the mask for global parameters. The tripping schedules of all relays, which are in the schedule of the selected relay, are also built. When opening the relay window (clicking "Characteristics" in the DP-relay mask), the program asks, whether the tripping schedules should be rebuilt or not, if the schedules have been built already. The schedules must be rebuilt, when the network data or the topology has been changed.
Edit The tripping schedules of the selected relay can be edit. After having selected this option the generated schedules are listed. All nodes are listed, which are connected with the ending node of the protected line. The relay location is not displayed, because it will always be the first node in the schedules. The available options are: D.backward, D.forward Pressing this option the schedules in forward or backward direction are displayed. Edit With this option the selected tripping schedule can be edit. All nodes of this schedule (incl. relay location and ending node of the protected line) are listed. With the functions Delete the marked node can be deleted from the schedule. The first two nodes can not be deleted. With function Append a new node can be appended in the schedule. The program lists all possible nodes, which can be appended. These are nodes, which are connected through an element with the last node in the schedule. The element is also displayed. In general only the nodes, which are in the predefined fault distance in positive and negative direction from the relay location are listed respectively can be appended. A node (in the predefined distance from the relay) will no more be listed, if this node has been deleted from all schedules. Therefore it is advisable to build-up first the desired schedule and afterwards to delete nodes or whole schedules.
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Distance Protection
Append This option appends a new schedule. With "Edit" the desired schedule can be built-up (see above). Delete A tripping schedule can be deleted with this option.
Scrolling forward/backward This option scrolls the pages of the tripping schedule, if the schedule is displayed in different pages (see number of pages in section "Dimensions" on page 10-22).
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Procedure for Entering a Relay For the input and setting of a relay the following procedure has to be done: • Step: Insert all distance protection relay in the network. This can be done graphic- or list-oriented. Each relay has an identifier. • Step: Insert to each DP-relay current (CTs) and voltage transformers (VTs). The VTs are also assigned to an element and not to a node. If several elements leads to a node, it is sufficient, to insert one VT to one of these elements. • Step: Select a relay (mask and afterwards relay window) and look at the parameters. In the global parameters the input values "fault type" and "fault distances" are important. In the relay-specific parameters the user can choose, whether he likes to work with primary or secondary impedance values. • Step: Let the program generate the tripping schedules. Check the tripping schedules and if necessary change or delete them. It is important that the relay location will not appear twice in a schedule. This can happen in meshed networks. With the delete function the relay location and/or undesired nodes can be eliminated. • Step: With correct tripping schedules, the starter and tripping characteristics can be entered. Especially for the automatic relay setting, a correct tripping schedule is important. When generating the tripping schedule, all nodes, which are reducable, are not considered (see "Node Data" in chapter "Element Data Input and Models"). Remark: A DP-relay, which is located in a node (sleeve) between a disconnect/load switch and a line, will be relocated to the correct bus bar by the program, if the sleeve respectively the switch will be reduced. A
B H1
DP
DP
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Distance Protection
Relay Documentation With the menu option "Relay - Documentation - Present relay" the documentation of the present relay can be done. To get zero sequence impedances set the fault type to asymmetrical fault in the global parameters. The documentation consists of three pages. Relay settings ************** Relay name Description Relay type Relay location Branch Line length /km
: : : : : :
DSR-41 ABB-REL316 ONODE 1 L-002 5.0
Network impedances(primary): ---------------------------1.stage 2.stage X(1)tot /Ohm : 1.088 2.169 R(1)tot /Ohm : 3.202 7.383 Z(1)tot /Ohm : 3.382 7.695 Phi(1) /G : 18.763 16.370
3.stage (see below)
4.stage
----------------- Zero impedances -----------X(0)tot /Ohm : 5.748 20.702 R(0)tot /Ohm : 7.064 24.143 Z(0)tot /Ohm : 9.107 31.804 Phi(0) /G : 39.137 40.612
k0 phi(k0) RE/RL XE/XL
----------------: 0.597 : 31.590 : 0.402 : 1.428
Earth factors ------------1.082 (see below) 31.506 0.757 (see below) 2.849
Parameters: (Input values) ----------Voltage transfor.: Ur1 /V: Ur2 /V: Current transfor.: Ir1 /A: Ir2 /A: Ratio : Ki/Ku : Arc resistance Ph-Ph RfLL Arc resistance Ph-E RfLE Tower earthing resistance RM
20000 100 20000 100 0.25
/Ohm : /Ohm : /Ohm :
Distributed reactance X'(sec)/Ohm/km : (distributed line reactance)
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Relay location 1.
2.
Impedance stage 1
Impedance stage 2
3.
Stage
Z / Ohm
Impedance stage 3
The impedance values of stage 1 represent the line impedance or the impedance to the next relay node. The impedance values are given for the positive and zero system. To get the values of the zero the fault type in the global parameters must be set to an asymmetrical fault. In order to get the line impedance between stage 1 and 2 a subtraction of the impedance values of stage 2 and 1 must be done. The following values for each stage are also given: k0 = (Z(0) - Z(1)) / (3*Z(1)) RE/RL = 1/3*(R(0)/R(1) - 1) XE/XL = 1/3*(X(0)/X(1) - 1) The second page shows the set values for a general relay, that means independent of its type. Set values (relay independent): ------------------------------primary 1.stage X1 /Ohm : 0.925 R1 /Ohm : 2.722 R1+RfLL/2 /Ohm : 2.722 R1+RfLE+RM /Ohm : 2.722 X0 /Ohm : 4.886 R0 /Ohm : 6.004 2.stage X1 R1 R1+RfLL/2 R1+RfLE+RM X0 R0
secondary 0.231 0.680 0.680 0.680 1.222 1.501
0.100
0.100
0.600
0.600
/Ohm /Ohm /Ohm /Ohm /Ohm /Ohm
: : : : : :
2.098 6.195 6.195 6.195 4.886 6.004
0.525 1.549 1.549 1.549 1.222 1.501
Overreach stage X1 /Ohm R1 /Ohm R1+RfLL/2 /Ohm R1+RfLE+RM /Ohm
: : : :
1.305 3.842 3.842 3.842
0.326 0.961 0.961 0.961
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Time(L-L, L-E)
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Distance Protection
X0 R0
/Ohm : /Ohm :
6.898 8.477
1.724 2.119
Direct. final stage /s : 4 Non-dir. final stage /s : Starter -------
(type of starter)
Overcurrent starter
:
IL(*Ir1) IS(*Ir1)
: 2 :
The third page will only be displayed when working with the predefined relay types. The values for the setting parameters are shown, e.g. ABB REL316. Set values (primary): ---------------------
X /Ohm R /Ohm RR /Ohm RRE /Ohm k0 k0Ang Time /s
: : : : : : :
1.stage 0.925 2.722 2.722 2.722 0.597 31.590 0.100
Starter ------XA /Ohm XB /Ohm RA /Ohm RB /Ohm Rload /Ohm AngleLoad /G
: : : : : :
2.stage 2.098 6.195 6.195 6.195 1.017 33.065 0.600
3.stage
Ov.stage 1.305 3.842 3.842 3.842
Bw.stage
9 -8 8 -6 5 45.0
Remarks: -------............................................................ ............................................................ ............................................................
............................................................
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Checking the Relay Settings After having set all relays, the settings can be checked. Several variants (different fault locations, faults on lines, arbitrary fault types) can be calculated now and the program calculates the tripping times of the relays. The evaluation can be done according to: • fault location • relay location. The above described options can be selected from "Calculation - Distance Protection" in the main menu.
Fault Locations The input of fault locations is described in chapter "Short Circuit".
Line Faults See chapter "Short Circuit".
Evaluation According to Fault Locations After having selected this option short circuits are calculated in all faulted nodes. All relay in the predefined fault distances from the faulted node are checked. The results are listed in a text file, which name has to be entered in the mask for global parameters. The list is node-oriented and is shown below:
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Distance Protection
+-----------------------------------------------------------------------+ | | | Fault location: AU_BB12 | | | |-----------------------------------------------------------------------| |DP-Relay (prim.)|Di| I/kA | AI/D | U/kV | AU/D | Z/Ohm | AZ/D | t/s | | | |L1,2,3 | |L1,2,3 | | 120 | 120 | | |-----------------------------------------------------------------------| |DSR-5 | 1| 0.247| 75.3| 4.205| 110.6| 5.08| 18.7|0.600| | | | 0.022| -69.6| 37.680| 198.9| 5.08| 18.7| | | | | 0.026| 233.4| 43.799| 143.1| 19.93| 43.7| | | | |- 120 -|------|- 120 -|------| X/Ohm | R/Ohm|-----| | | | 0.096| 76.6| 22.433| -3.1| 1.62| 4.81| | | | | 0.083| 74.6| 0.874| -78.9| 1.62| 4.81| | | | | 0.068| 74.4| 24.792| 165.9| 13.78| 14.40| | |-----------------------------------------------------------------------| |DSR-41 | 2| 0.158| 77.6| 5.647| 109.8| 11.07| 17.1|1.200| | | | 0.045| -71.3| 37.783| 198.4| 11.07| 17.1| | | | | 0.051| 237.0| 44.241| 143.1| 40.91| 40.3| | | | |- 120 -|------|- 120 -|------| X/Ohm | R/Ohm|-----| | | | 0.079| 80.2| 22.348| -2.0| 3.26| 10.58| | | | | 0.055| 75.7| 0.554| -75.2| 3.26| 10.58| | | | | 0.024| 73.6| 25.281| 164.8| 26.45| 31.21| | |-----------------------------------------------------------------------| |DSR-42 | 2| 0.086| 74.1| 5.647| 109.8| 21.69| 21.7|3.000| | | | 0.024| -69.5| 37.783| 198.4| 21.69| 21.7| | | | | 0.029| 226.3| 44.241| 143.1| 71.96| 44.1| | | | |- 120 -|------|- 120 -|------| X/Ohm | R/Ohm|-----| | | | 0.044| 76.7| 22.348| -2.0| 8.01| 20.16| | | | | 0.028| 70.7| 0.554| -75.2| 8.01| 20.16| | | | | 0.014| 73.3| 25.281| 164.8| 50.06| 51.70| | |-----------------------------------------------------------------------|
Fig. 10.5 Evaluation according to fault location
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Distance Protection
The abbreviations are: Fault location:
Name of fault location
DP-Relay:
Name of relay, whose results are listed.
Di:
Distance of the relay location from the fault location.
I:
Current (phase and symmetrical component values) in kA, which flows through the relay when short circuit occurs in the fault location.
AI:
Angle of current in degree, which flows through the relay when short circuit occurs in the fault location.
U:
Voltage (phase and symmetrical component values) in kV at relay location when short circuit occurs in the fault location.
AU:
Angle of voltage in degree at relay location when short circuit occurs in the fault location.
Z:
Impedance (symmetrical component value) in Ohm, which is seen from the relay when short circuit occurs in the fault location.
AZ:
Angle of impedance in degree, which is seen from the relay when short circuit occurs in the fault location.
R:
Resistance (symmetrical component value) in Ohm, which is seen from the relay when short circuit occurs in the fault location.
X:
Reactance (symmetrical component value) in Ohm, which is seen from the relay when short circuit occurs in the fault location.
t
Tripping time of the relay.
All values are given as primary values.
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Distance Protection
Evaluation According to Relay Location The same is to say as in the previous section. The list is relay-oriented and is shown above: +-----------------------------------------------------------------------+ | | | Relay : DSR-41 | | Relay location : ONODE 1 | | To node : ONODE 2 | | Branch : L-002 | | | |-----------------------------------------------------------------------| |Fault location |Di| I/kA | AI/D | U/kV | AU/D | Z/Ohm | AZ/D | t/s | | | |L1,2,3 | |L1,2,3 | | 120 | 120 | | |-----------------------------------------------------------------------| |ONODE 1 | 0| 0.230| 86.3| 0.000| 0.0| 0.00| 0.0|0.100| | | | 0.040| -61.1| 38.391| 207.1| 0.00| 0.0| | | | | 0.042| 236.9| 39.723| 148.1| 0.00| 0.0| | | | |- 120 -|------|- 120 -|------| X/Ohm | R/Ohm|-----| | | | 0.100| 86.9| 22.428| -1.8| 0.00| 0.00| | | | | 0.076| 85.7| 0.506| -63.7| 0.00| 0.00| | | | | 0.053| 86.0| 22.671| 177.0| 0.00| 0.00| | |-----------------------------------------------------------------------| |ONODE 2 | 1| 0.149| 85.4| 1.344| 115.9| 3.38| 18.8|0.100| | | | 0.045| -64.9| 38.320| 205.0| 3.38| 18.8| | | | | 0.047| 241.0| 40.852| 147.0| 9.11| 39.1| | | | |- 120 -|------|- 120 -|------| X/Ohm | R/Ohm|-----| | | | 0.076| 86.6| 22.412| -1.9| 1.09| 3.20| | | | | 0.051| 84.7| 0.515| -66.2| 1.09| 3.20| | | | | 0.022| 82.9| 23.319| 174.1| 5.75| 7.06| | |-----------------------------------------------------------------------| |AU_BB12 | 2| 0.158| 77.6| 5.647| 109.8| 11.07| 17.1|1.200| | | | 0.045| -71.3| 37.783| 198.4| 11.07| 17.1| | | | | 0.051| 237.0| 44.241| 143.1| 40.91| 40.3| | | | |- 120 -|------|- 120 -|------| X/Ohm | R/Ohm|-----| | | | 0.079| 80.2| 22.348| -2.0| 3.26| 10.58| | | | | 0.055| 75.7| 0.554| -75.2| 3.26| 10.58| | | | | 0.024| 73.6| 25.281| 164.8| 26.45| 31.21| | |-----------------------------------------------------------------------|
Fig. 10.6 Evaluation according to relay location
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NEPLAN User's Guide V5
Distance Protection
The abbreviations are: Relay:
Name of relay, whose results are listed.
Fault location: Name of fault location Di:
Distance of the relay location from the fault location.
I:
Current (phase and symmetrical component values) in kA, which flows through the relay when short circuit occurs in the fault location.
AI:
Angle of current in degree, which flows through the relay when short circuit occurs in the fault location.
U:
Voltage (phase and symmetrical component values) in kV at relay location when short circuit occurs in the fault location.
AU:
Angle of voltage in degree at relay location when short circuit occurs in the fault location.
Z:
Impedance (phase and symmetrical component values) in Ohm, which is seen from the relay when short circuit occurs in the fault location.
AZ:
Angle of impedance in degree, which is seen from the relay when short circuit occurs in the fault location.
R:
Resistance (phase and symmetrical component values) in Ohm, which is seen from the relay when short circuit occurs in the fault location.
X:
Reactance (phase and symmetrical component values) in Ohm, which is seen from the relay when short circuit occurs in the fault location.
T
Tripping time of the relay.
All values are given as primary values. Additionally the relay location, the protected element and its ending node are listed. The branch impedance in Ohm is also given. The factor k0 (amount, angle) gives the complex ratio between the branch impedances of the zero sequence and the positive sequence system.
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Distance Protection
10-38
NEPLAN User's Guide V5
Harmonic Analysis
Harmonic Analysis Calculation Parameters (HA) The calculation parameters are entered with the help of a "Parameters" dialog. It consists of the three tabs Frequency Scanning, Harmonic Level Calculation and Options, which are explained here. Frequency scanning Frequency scanning Frequency scanning
Indicates, if Frequency scanning will be done when selecting the calculation.
Frequency start
Starting frequency for the calculation in Hz.
Frequency end
Ending frequency for the calculation in Hz.
Frequency step
Frequency step for the calculation in Hz (see "Theory of Harmonic and Audio Frequency Analysis" on page 11-3).
Variable step length control
If active, the frequency step will be adjusted automatically during impedance calculation if large impedance changes occur. If not active, the impedances are calculated with given and constant step.
Scanning according to
Frequency scanning can be done according to • Z: Scanning a node impedance • I: Scanning a current of one harmonic current source (only one must be present and active in the network) • U: Scanning a voltage of one harmonic voltage source (only one must be present and active in the network).
Harmonic Load flow Harmonic load flow calculation
Indicates, if a Harmonic Load flow will be done when selecting the calculation.
Harmonic for Harmonic load flow
The harmonic for which the load flow must be calculated.
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11-1
Harmonic Analysis
Harmonic Level Calculation Harmonic Level calculation
Indicates, if Harmonic level calculation will be done when selecting the calculation.
Harmonic limit All harmonics in the harmonic current and voltage sources are considered up to the given limit. S for THDi calculation
Apparent power in MVA for calculating the nominal current of the elements. The nominal current of the elements are used for calculation the distortion factor THDi.
Sum of harmonic values Vectorial
If there are several harmonic sources in the network the sum of harmonics will be calculated vectorial (see below).
Geometric
If there are several harmonic sources in the network the sum of harmonics will be calculated geometrically (see below).
IEC 1000-2-6
If there are several harmonic sources in the network the sum of harmonics will be calculated according to IEC 1000-2-6 (see below).
Arithmetic
If there are several harmonic sources in the network the sum of harmonics will be calculated arithmetically (see below).
Options Reduction of switches circuit breakers and couplers Reduce
If this option is checked, all switches, circuit breakers and busbar couplers are reduced.
Result file File
File name, which can be selected.
Write after calculation
If checked, the result file will be created after the calculation.
Format 4.x
If checked, the result file will be created as in program version 4.x.
Select
To select the nodes and elements, whose variable should be stored and displayed.
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NEPLAN User's Guide V5
Harmonic Analysis
Theory of Harmonic and Audio Frequency Analysis The operating behavior of the networks at frequencies above 50/60 Hz has to be simulated in order to examine the harmonics as well as the level of AF ripple control signals in power networks. The following models are required: • Network elements (lines, filters, loads, synchronous machines..) • Harmonic sources (converter, AF ripple control transmitters...) Network elements The network elements are represented by their equivalent circuit elements: resistance (R), inductance (L) and capacitance (C). A balanced three-phase system is assumed, so that a single-phase representation of the network in the positive sequence system will be examined. In general the resistances and inductances of the network elements are frequency-dependent (see “Frequency dependence” in chapter “Element Data Input and Models”), for example by current displacement (skin effect). In general the resistances are increasing with higher frequencies and the inductances are decreasing. The capacitances are practically frequency-independent. The frequency-dependency of the elements can be entered in three different manners. For all frequencies the resistance and the inductance of the equivalent circuit have to be recalculated. Sources There is a difference between current and voltage sources. Current sources inject the source current into the network. Voltage sources engrave a source voltage on the network node. The sources are need to reproduce the • equipment with non-linear current-voltage-characteristic • AF ripple control transmitters. Sources with non-linear current/voltage characteristics are for example converter and arc furnaces. As a rule these equipments are represented by a current source for harmonics. The harmonic currents with their frequencies, amplitudes and phase angles depend on the construction and operation of these equipments. In case of an arc furnace these are statistic values depending on the particular furnace. In ideal case the harmonic currents of converters can be calculated as following: Ik =
1 ⋅I k 1
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11-3
Harmonic Analysis
with: k = n ⋅ p ±1;
n = 1,2,3,....
It means: Ik: I1: p:
k-th harmonic current first harmonic current pulse number of converter
For details there are more information in the literature. AF ripple control transmitters inject a voltage or current with a well-known frequency in the network. There are two possibilities in coupling the parallel injection and the series injection. Calculation Algorithm For a harmonic calculation the following steps for each interesting frequency will be made: • Determination of the equivalent-circuit elements R (f), L(f) (frequency dependent) and C. • Creating of the admittance matrix for the network • Solution of the linear equation system I(f)=Y(f) · U(f) It means: I(f): Y(f): U(f):
vector of node currents at frequency f Y-matrix at frequency f vector of node voltages at frequency f
For harmonic or AF ripple control calculation the harmonic generators or the AF ripple control transmitters are represented by their equivalent circuits (current or voltages sources). For impedance calculation the program will take a fictious current source (1.0 pu) for the interesting node. A constant amplitude, a constant phase angle and a frequency range will be related to the source. For all frequencies in this range the program calculates the voltage at the interesting nodes. With the ratio of voltage and current for all frequencies the program calculates the impedances (amount and angle). The impedance calculation is made with the following frequencies, which will be calculated with the calculation parameters.
f k = fanf + k ⋅ fdelta ≤ fend It means:
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NEPLAN User's Guide V5
Harmonic Analysis
fk:
k-th harmonic, k = 0, 1, 2, ...
If the corresponding check box in the calculation parameter mask is checked, the program will examine the amount and the angle of the impedance for large differences between two successive frequency steps. If large differences occur the frequency step will be automatically adjusted according to following formulas:
K1 = 5 ⋅ log
Zalt Zneu
K 2 = 0.05 ⋅ ϕ alt − ϕ neu If it is valid K1 > 2, that means Zold / Znew > 2,5 or Zold / Znew < 0,4 or K2 > 2, that means ϕ alt − ϕ neu > 40° , the automatic frequency adjustment occurs. K will be set to the larger value of K1 and K2: K = Maximum (K1, K2). With this value the new frequency step will be calculated
fdelta =
fdelta K
As soon as the condition K>2 is no more fulfilled, the frequency step will be calculated according to the user’s input with fstep. It means: Zold: Znew: Phiold: Phinew:
impedance value (amount) at old frequency impedance value (amount) at new frequency angle of impedance at old frequency angle of impedance at new frequency.
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11-5
Harmonic Analysis
Addition of harmonics from different sources In reality harmonics add always vectorial to each other. So, the sum of two harmonic sources (voltage or current) with equal amplitude can vary considerably: between 0% and 200%. The problem is that in practice the harmonic angles in the sources are unknown. Therefore there are four different ways to make the addition of harmonics, which come from different sources: - vectorial - geometrically - according to IEC 1000-2-6 - arithmetically For each harmonic source and each harmonic the network equation I ( f ) = Y ( f ) • U ( f ) will be solved. The angle given in the harmonic sources are not considered for all calculations, except for vectorial sum calculation. After having calculated all voltages for each source and harmonic the sum can be built: Vectorial The sum is built up vectorial: U h = U h1 + U h 2 + U h3 + ... Geometrically The sum is built up geometrically: U h = U h1 2 + U h 2 2 + U h 3 2 + ... IEC 1000-2-6 The sum is built up according to IEC-1000-2-6: U h = k1 ⋅ U h1 + k 2 ⋅ U h 2 + k 3 ⋅ U h3 + ... Arithmetically The sum is built up arithmetically: U h = U h1 + U h 2 + U h 3 + ... The abbreviations are: Uh: Node voltage for harmonic h Uh1: Node voltage for harmonic h caused by harmonic source 1 Uh2: Node voltage for harmonic h caused by harmonic source 2 Uh3: Node voltage for harmonic h caused by harmonic source 3 k1: Diversity factor for harmonic h and harmonic source 1 k2: Diversity factor for harmonic h and harmonic source 2 k3: Diversity factor for harmonic h and harmonic source 3
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NEPLAN User's Guide V5
Harmonic Analysis
The size of ki is dependent on the harmonic order h and the ratio between the node voltage Uhi caused by the single harmonic source i and the arithmetically calculated node voltage Uh. For further information please refer to IEC 1000-2-6. The vectorial sum is mathematically the correct one, but because of unknown angles of the harmonics maybe in practice very incorrect. The geometrical sum gives the smallest value, the arithmetical sum the highest value. If the node voltage for the h-th harmonic is known the harmonic currents for all branches can be calculated. Characteristics The following characteristics are important for harmonic analysis: • percentage harmonic voltage uk of the h-th harmonic uh =
Uh Un 3
It means: Uk: Un:
r.m.s.-value of the k-th harmonic voltage (phase-to-earth) nominal system voltage
• r.m.s-value of power frequency voltage (geometrical sum): U = U 1 + U 2 + U 3 + ... 2
2
2
• r.m.s-value of power frequency current (geometrical sum): I = I1 + I 2 + I 3 + ... 2
2
2
• r.m.s-value of harmonic voltage (geometrical sum): U = U 2 + U 3 + U 4 + ... 2
2
2
• r.m.s-value of harmonic current (geometrical sum): I = I 2 + I 3 + I 4 + ... 2
2
2
• Voltage Distortion Factor in %:
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Harmonic Analysis
U 2 + U 3 + .... THD = ⋅ 100% U1 2
2
with U1 = Un
• Current Distortion Factor in %: I 2 + I 3 + .... 2
THDi =
2
I1
⋅ 100%
with I 1 =
Un ⋅Un STHDi
• TIF: TIF =
∑ (I
⋅ Wh )
2
h
I1
with I 1 =
Un ⋅Un and Wh=5⋅Ph⋅h⋅fn STHDi
• IT: IT =
∑ (I
⋅ Wh )
2
h
It means: U1: U2: U3: I1: I2: I3: STHDi: Wh: fn: h: Ph:
amount of voltage of first (fundamental) harmonic amount of voltage of second harmonic amount of voltage of third harmonic amount of current of first (fundamental) harmonic amount of current of second harmonic amount of current of third harmonic input value (see calculation parameters) single frequency TIF weighting factor at frequency f = h⋅fn according to IEEE 519 nominal system frequency harmonic C message weigthing factor at frequency f = h⋅fn according to IEEE 519
Filter characteristics Three types of filters can be defined (see description of filter dialog): - normal filter - HP-filter - C-filter. The following values are calculated for filters: IL(FH) 11-8
fundamental harmonic (nominal system frequency fn) current value NEPLAN User's Guide V5
Harmonic Analysis
of the inductance L +IL(RMS): rms current value of the inductance L. +IL(ari): total current value (calculated arithmetically) of the inductance L. IC(FH): fundamental harmonic (nominal system frequency fn) current value of the main capacitance C +IC(RMS): rms current value of the main capacitance C. +IC(ari): total current value (calculated arithmetically) of the main capacitance C. Ird(FH): fundamental harmonic (nominal system frequency fn) current value of the damping resistance Rd. Ird(RMS): rms current value of the damping resistance Rd. PRd(FH): fundamental harmonic (nominal system frequency fn) resistive losses in kW in the damping resistance Rd. PRd(tot): total resistive losses in kW in the damping resistance Rd caused by Ird(RMS), PRd(tot) = 3·Rd·Ird(RMS)2 PL(tot): total resistive losses in kW in the reactor caused by caused by IL(RMS), PL = 3·Rv·IL(RMS)2 UCsu: Arithemic sum of fundamental harmonic voltage and r.m.s-value of harmonic voltage at auxiliary capacitance Cs (only for C-filters).
∑UCs
UCsu = UCs1 +
UCsi:
ICs 1.3 ⋅ 2 ⋅ π ⋅ f n ⋅ Cs
Voltage at nominal system frequency fn, which causes the same reactive power at the auxiliary capacitance Cs, as the arithmetic sum of all reactive powers caused by the nominal system frequency and the harmonic frequencies (only for C-filters). UCsq =
UCu:
∑h⋅ f
0
⋅ UCs h
2
for h=1, 2, 3,…
Arithemic sum of fundamental harmonic voltage and r.m.s-value of harmonic voltage at main capacitance C. UCu = UC1 +
UCi:
for h = 2, 3, …
Minimum rated capacitance voltage at which ICs can be transmitted (IEC 871). ICs is 1.3 times the current at nominal system frequency fn, which is calculated if UCsi is applied at the auxiliary capacitance Cs (only for C-filters). UCsi =
UCsq:
2 h
∑UC
2 h
for h = 2, 3,…
Minimum rated capacitance voltage at which IC can be transmitted (IEC 871). IC is 1.3 times the current at nominal system frequency fn, which is calculated if Uci is applied at the main capacitance C.
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Harmonic Analysis
UCi =
UCq:
Voltage at nominal system frequency fn, which causes the same reactive power at the main capacitance C, as the arithmetic sum of all reactive powers caused by the nominal system frequency and the harmonic frequencies. UCq =
11-10
IC 1 .3 ⋅ 2 ⋅ π ⋅ f n ⋅ C
∑h⋅ f
0
⋅ UC h
2
for h=1, 2, 3,…
NEPLAN User's Guide V5
Harmonic Analysis
Results (HA)
Select Results The nodes and elements to be presented in the result table, may be selected here. The values displayed at the diagram can be selected in the Harmonic Analysis tab of the “Edit – Diagram Properties” dialog.
Results Table The results can be represented in different tables, each with its specifique information. Node impedances The node impedances are shown for the pre-selected nodes. This is a result getting from a frequency scanning Zimpedance. Node results
The results of the nodes will be displayed. This is a result of either a frequency scanning U/I or a level calculation or or a harmonic load flow.
Element results
General results of elements will be displayed. This is a result of either a frequency scanning U/I or a level calculation or a harmonic load flow.
Filter results
All results of the filters will be displayed. This is a result of a level calculation.
Result files
It’s possible to export results to a *.ros file by selecting the file and pressing the respective button. These result files can be read by external programs, such as Excel and the results can be evaluated in an arbitrary way. The File can be written in the old Format 4.x or in a new Format for V5.x.
Below you find a description of the output variables in the result tables: Node impedances: f
Frequency in Hz.
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Harmonic Analysis
Z
Impedance in Ohm.
Z ang
Angle of impedance in °.
Node results: ID
Identification number (ID) of the node.
Name
Node name.
THD
Distortion factor in %.
f
Frequency in Hz.
U
Node voltage in V (line-line value)
u [%]
Node voltage in % in respect to nominal node voltage.
U ang
Voltage angle in °.
Description
Description of the node.
Zone
Zone, the node belongs to.
Area
Area, the node belongs to.
Partial network
Number of the partial network, the node belongs to.
Element results: ID
Identification number (ID) of the element.
From
Name of starting node of element (From node)
To
Name of ending node of element (To node)
Element name
Name of the element.
Type
Type of element.
THDi
Current distortion factor in %.
TIF
TIF factor.
IT
IT factor.
F
Frequency in Hz.
I1, I2, I3
Current at “From node”, “To node”, “Tertiary node” in A.
I1ang, I2ang, I3ang
Current angle at “From node”, “To node”, “Tertiary node” in °.
U12, U31, U23
Voltage (line-line values) between “From node” and “To node” and “Tertiary node” in V.
U12ang, U31ang, Angle of voltages between “From node” and “To node” and U23ang “Tertiary node” in °. Description
11-12
Description of the element.
NEPLAN User's Guide V5
Harmonic Analysis
Zone
Zone, the element belongs to.
Area
Area, the element belongs to.
Partial Network
Number of the partial network, the element belongs to.
Filter results: Please see section “Filter characteristics”.
Graphical Results To open the graphical result window choose "Analysis – Harmonic Analysis Graphical Results...". Subchart settings: Chart name
Name of chart.
Add, Edit Delete curve
Push buttons to add, edit and delete curves in the diagram.
Harmonic Analysis Results Curve name
Name of curve
Variant
Name of Variant or Rootnet.
Variable name
The variable name can be selected. Three options are available: - Nodes variable - Elements variable - Level limit curve.
Element name, ID
Name of element, whose results are displayed.
Variable
Variable to be displayed.
File path
File name and path for limit curve.
Limit curve
Limit curve to be displayed. In the file several curves can be stored. To display all curves in the file, please add new curve.
Axis properties Select axis
Select axis whose settings have to be displayed / changed.
Title
Axis title. Only enabled if the corresponding check box “Automatic” is not checked.
Resolution
Specifies the resolution of the steps in between labels. Only enabled if the corresponding check box “Automatic” is
NEPLAN User's Guide V5
11-13
Harmonic Analysis
not checked. No of digits
Number of label digits. Only enabled if the corresponding check box “Automatic” is not checked.
Min
Sets the axis minimum value. Only enabled if the corresponding check box “Automatic” is not checked.
Max
Sets the axis maximum value. Only enabled if the corresponding check box “Automatic” is not checked.
Grid
If checked grid lines are displayed.
Legend Show legend
If checked, legend will be displayed
Height
Height of legend in % of sub chart size
The format of the current limit file is given in the appendix.
11-14
NEPLAN User's Guide V5
Motor Starting
Motor Starting Calculation Parameters (MS) The calculation parameters are entered with the help of a "Parameters" dialog, which is explained here. Time simulation End time
End time for the simulation in s.
Time interval
Time interval for the simulation in s.
Reduction factor for time interval
Factor for reducing the time interval. During the simulation, the time interval will be reduced by this factor, when the motor slip s will be less than 0.2. After reaching the steady state point the time interval will be reset to entered value.
Transformer regulation considered after time
Time delay for regulating transformers in s. After the given time the automatic regulation of the transformers will be activated. This value is only important, if the parameter "Automatic transformer regulation” is checked in the load flow parameters.
Result storage Points to be saved per variable
The user can enter the number of points to be saved for the marked elements during the simulation. In this way the graphical output will be influenced (layout and speed).
Result display Result display
Output units. For low voltage in "V, A, kVA" or high voltage in "kV, kA, MVA".
Only the results of the pre-selected nodes and elements are stored and can be displayed. The selection can be done with the menu option “Analysis – Motor Starting – Select results” or the push button “Select results”. The motor starting is dependent on the parameters set in the load flow. To change load flow parameters press push button “LF-parameters”.
NEPLAN User's Guide V5
12-1
Motor Starting
Theory of Motor Starting Calculation The motor starting simulation is a sequence of load flow calculations. In every calculation resp. time step (load flow) the impedance of the asynchronous machine will be changed in function of the increasing speed and resistance (eddycurrent losses) as well as the leakage reactance (decreasing of the saturation). The theory of the load flow calculation is explained section "Theory of Load Flow Calculation" in chapter "Load Flow". The equivalent circuit of an asynchronous machine is given below: R1
X1
X2(s)
Xh
R2(s)/s
Fig. 12.1 Asynchronous machine equivalent circuit
For more information about this model see “Asynchronous Machine – Model” of the chapter “Element Data Input and Models”.
To consider the voltage drop at the terminal of an infeed element (generator, feeder, power system unit) the following model will be used:
Netw. node
Xd
Dummy node
Fig. 12.2 Equivalent circuit of an infeed element
For every infeed element a dummy node will be created. Between the real network node and the dummy node the reactance Xd = 1.5 * Xd" (Xd":
12-2
NEPLAN User's Guide V5
Motor Starting
subtransient reactance) will be inserted. The reactance Xd" can be calculated from the input values. The dummy nodes are named by the program. Their names start with the character "@". The type of the network node (SL, PQ or PV) will be automatically assigned to the dummy node and the network node will become a normal PQ-node. The voltage of the network node is free adjustable and will be calculated by the program. The start-up of a motor will be described by the motion equation: Me - Ml = - 2 · Pi · J · n0 / p · ds/dt with Me: Ml: J: n0: p: s:
Electromagnetic torque load torque moment of inertia synchronous speed numbers of pole pairs Slip
The electromagnetic torque is described by the equation: Me = p / (2 · Pi · n0) · R2 · I22 / s with I 2:
rotor current in circuit (R2, X2)
The load torque is described by the equation: Ml = M0 + (1 - s) · M1 + (1 - s) 2 · M2
(parabola)
or Ml = Ml(s)
(characteristic)
with M0, M1, M2: Ml(s):
input values (see "Theory of Motor Starting Calculation" on page 12-2) starting load characteristic, input values as well (see "Theory of Motor Starting Calculation" on page 12-2)
If a motor will not be started-up, the steady state point will be • calculated with the help of the operating load and the electromagnetic torque ("LF-Type" must be set to "Mload")
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Motor Starting
• set as constant power load P and Q ("LF-Type" must be set to "PQoper"). The calculation of the steady state point with the help of the load characteristic consists also of a sequence of load flow calculations. The steady state point that means the crossing of the torque curves will be calculated with the NewtonRaphson algorithm.
Voltage Drop Selecting the corresponding menu option the voltage drop at time t=0.0 due to starting motors is calculated. The calculation will be done as explained in section "Theory of Motor Starting Calculation" on page 12-2. The difference is, that less data have to be entered for the motors. For example the moment of inertia J, all time data, load characteristics can be dropped.
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Motor Starting
Results (MS)
Select Results The nodes and elements to be presented in the result table, may be selected here.
Results tables The results are represented in a table. ID
Identification number (ID) of the node.
Name
Name of node or element.
t
Simulation time in s.
U
Node voltage in kV at time t.
I
Current in kA of the element at time t.
P
Active power in MW of the element at time t.
Q
Reactive power in Mvar of the element at time t.
Me
Electrical machine torque in Nm at time t.
Ml
Load torque in Nm at time t.
s
Machine slip at time t.
n/nr
Ratio between rotor speed at time t and nominal speed.
Graphical Results To open the graphical result window choose "Analysis – Motor Starting Graphical Results...".
Subchart settings: Chart name
Name of chart.
Add, Edit Delete curve
Push buttons to add, edit and delete curves in the diagram.
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Motor Starting
Motor Starting Results Curve name
Name of curve
Variant
Name of Variant or Rootnet.
X-Axis variable Time
If checked, the x-axis is always the time axis. If not checked, all selection as for Y-axis are possible.
Y-Axis variable Element type
Type of Element. Three options are available: - Asynchronous machine - Element - Node
Element name, ID
Name of element, whose results are displayed. Only the pre-selected nodes or elements are displayed.
Variable
Variable to be displayed.
Axis properties Select axis
Select axis whose settings have to be displayed / changed.
Title
Axis title. Only enabled if the corresponding check box “Automatic” is not checked.
Resolution
Specifies the resolution of the steps in between labels. Only enabled if the corresponding check box “Automatic” is not checked.
No of digits
Number of label digits. Only enabled if the corresponding check box “Automatic” is not checked.
Min
Sets the axis minimum value. Only enabled if the corresponding check box “Automatic” is not checked.
Max
Sets the axis maximum value. Only enabled if the corresponding check box “Automatic” is not checked.
Grid
If checked grid lines are displayed.
Legend Show legend
If checked, legend will be displayed
Height
Height of legend in % of sub chart size
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NEPLAN User's Guide V5
Network Reduction
Network Reduction Introduction This program module allows to reduce any network to any number of boundary nodes, thus the behavior of the reduced network will be the same as the original one. This is for short circuit and load flow calculation. The reduced network will be represented with the help of series (see "Series Equivalents Data" in chapter "Element Data Input and Models") and shunt (see "Shunt Equivalents Data" in chapter "Element Data Input and Models") equivalents as well as equivalent infeeds. Depending on the type of network reduction there are equivalents for short circuit and for load flow. The same equivalent can't be valid for load flow and short circuit.
Selection of the Network to be Reduced The selection of the network to be reduced, respectively the nodes is independent of the type of network reduction (load flow or short circuit). The node to be reduced can be selected after having chosen the menu option "Analysis - Network reduction - Network selection (LF)" (for load flow) or "Analysis - Network reduction - Network selection (SC)" (for short circuit). All nodes, which are selected in the list will be reduced for the corresponding calculation. When quitting the dialog box, the boundary nodes are set automatically.
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Network Reduction
Network Reduction for Load Flow A network will be reduced after having selected "Analysis - Network reduction Load flow". All nodes to be reduced will be erased from the project and the seriesand shunt equivalents as well as the equivalent infeeds or loads are generated. The generated equivalents can be listed in the variant manager. The graphical representation of these equivalents can be done as usual. The reduced network has the same behavior with respect to the load flow as the original network. If the original network should not be overwritten, the reduced network must be stored with an other file name.
Important remarks: 1. Boundary nodes are represented as PQ-nodes without voltage control. The node type and/or the voltage control become active if there is a synchronous machine connected to the boundary node. 2. Reduced automatically regulated tap changing transformers have no influence on changes in the reduced network. If the influence should be considered the initial and ending node of these transformers should not be reduced.
Network Reduction for Short Circuit A network will be reduced after having selected "Analysis - Network reduction Short circuit". All nodes to be reduced will be erased from the project and the series- and shunt equivalents as well as the equivalent infeeds or loads are generated. The generated equivalents can be listed in the variant manager. The graphical representation of these equivalents can be done as usual. The reduced network has the same behavior with respect to the short circuit as the original network. The network can be reduced dependent on the short circuit parameters for different short circuit faults and short circuit methods (see "Short Circuit Parameter" in chapter "Short Circuit"): Short circuit type: 3-phase short circuit Only the matrix of the positive system will be built up and reduced. In the reduced network only 3-phase short circuit can be calculated. 13-2
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Network Reduction
Asymmetrical short circuit The matrices of the positive, negative and zero system will be built up and reduced. In the reduced network any kind of short circuit can be calculated. Short circuit methods: IEC909 The nodal admittance matrix will be built up and reduced according to IEC909. In the reduced network only short circuits according to the mentioned method should be calculated (see "Theory of Short Circuit Calculation" in chapter "Short Circuit"). Superposition method The nodal admittance matrix will be built up and reduced according to superposition method. In the reduced network only short circuits according to the mentioned method should be calculated (see "Theory of Short Circuit Calculation" in chapter "Short Circuit"). ANSI/IEEE The nodal admittance matrix will be built up and reduced according to ANSI/IEEE method. In the reduced network only short circuits according to the mentioned method should be calculated (see "Theory of Short Circuit Calculation" in chapter "Short Circuit"). If the original network should not be overwritten, the reduced network must be stored with an other file name.
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13-3
Voltage Stability
Voltage Stability Calculation Parameters To change the voltage stability calculation options, select "Analysis - Voltage Stability - Parameters..." from the menu.
Sensitivity Analysis / Modal Analysis Enable U-Q sensitivity analysis
S
Enable Q-U modal analysis M
Enable U-Q sensitivity analysis for voltage stability calculation Enable Q-U modal analysis for voltage stability calculation
Options Buses without load elements
M
Q=0, constant: reactive power variation of buses without connected load elements is zero. Q variable: reactive power of buses without connected load elements is variable.
Maximum number of eigenvalues
M
Maximum number of stored eigenvalues
Limits for sensitivities / participation factors
S, M
Values smaller than …% of the maximum value aren’t stored.
Mutual bus sensitivities
S
Not only the bus self sensitivities ∂U i / ∂Qi , but also the mutual bus sensitivities ∂U k / ∂Qi are stored.
Bus participation factors
M
Bus participation factors are stored.
Results
Branch participation factors M
Branch participation factors are stored.
Generator participation factors
M
Generator participation factors are stored.
Eigenvectors
M
Eigenvectors are stored.
S: used by sensitivity analysis M: used by modal analysis
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Voltage Stability
U-Q Curves Enable computation of U-Q curves
Enable computation of U-Q curves for voltage stability analysis
Voltage interval Lower limit
First point of U-Q curves
Upper limit
Last point of U-Q curves
Increment
Distance between 2 points
Sign convention for reactive Determines if reactive power injection or reactive power power consumption is positive Select nodes
Select nodes whose U-Q curves have to be computed.
P-U Curves Enable computation of P-U curves
Enable computation of P-U curves for voltage stability analysis
Load scaling factor Lower limit
First point of P-U curves
Upper limit
Last point of P-U curves. Set to a high value (e.g. 106) if the voltage collapse point has to be the last point.
Initial increment
Maximum distance between 2 points, increment at the beginning of the simulation
Final increment
Minimum distance between 2 points, increment at the voltage collapse point. The increment is automatically adjusted from “Initial increment” to “Final increment”
P-U computations
List of defined P-U computations
Identifier
Name of computation
Loads
Number of selected loads to be scaled
Generators
Number of selected generators to be scaled
Buses
Number of bus voltages to be recorded
New
Insert a new item into the computation list
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Voltage Stability
Delete
Delete the selected item from the list
Select All
Enable all items
Select None
Disable all items
Elements…
Determine for the selected item the loads and the generators to be scaled and the bus voltages to be recorded.
The voltage stability analysis can be started selecting "Analysis - Voltage Stability - Calculation" from the menu. To perform voltage stability analysis for a partial network choose "Analysis - Voltage Stability - Partial Network...".
Result Files File name
File name or full file path name
…
Select full path name
Build after calculation
File is automatically built after calculations
Build export file
File is built.
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Voltage Stability
Results
Graphical Results To open the graphical result window choose "Analysis - Voltage Stability Graphical Results...". Subchart settings: Subchart type
Select results to be displayed
Add curves manually
If checked, curves have to be added using the tab “Curves”. If not checked, tab “Curves” isn’t visible and curves of the actual variant are automatically added according to the following 4 subchart settings.
Select eigenvalue
Eigenvalue selection (for participation charts)
Select bus
Bus selection (for mutual bus sensitivity chart)
Select U-Q curves
Select U-Q curves to be displayed (for U-Q curve chart)
Select P-U curves
Select P-U curves to be displayed (for P-U curve chart)
Axis properties Select axis
Select axis whose settings have to be displayed / changed.
Title
Axis title. Only enabled if the corresponding check box “Automatic” is not checked.
Resolution
Specifies the resolution of the steps in between labels. Only enabled if the corresponding check box “Automatic” is not checked.
No of digits
Number of label digits. Only enabled if the corresponding check box “Automatic” is not checked.
Min
Sets the axis minimum value. Only enabled if the corresponding check box “Automatic” is not checked.
Max
Sets the axis maximum value. Only enabled if the corresponding check box “Automatic” is not checked.
Grid
If checked grid lines are displayed.
Legend Show legend
If checked, legend will be displayed
Height
Height of legend in % of subchart size
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Voltage Stability
The tab “Curves” is visible only if “Add curves manually” is checked. Press the “Add Curve” button to add a new curve to the subchart. Press the “Edit Curve” button to change the settings of the selected curve. Curve settings: Curve name
Curve name used for the legend. This field is enabled only if “Create name automatically” is not checked.
Create name automatically
Create curve name automatically
Variant
Select variant
P-U computation
Select P-U computation. Enabled only for P-U curve charts.
Node name, ID
Select node. Enabled only for mutual bus sensitivity charts, U-Q curve charts and P-U curve charts.
Eigenvalue
Select eigenvalue. Enabled only for participation charts.
Result Tables To open the result tables choose "Analysis - Voltage Stability – Result Tables". The result tables display all calculated and stored numerical results.
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Voltage Stability
Theory
Introduction The analysis of voltage stability can be done using two different methods, time simulations and static methods. Time simulations capture the events and their chronology leading to instability. The computer tries to solve the differential equations describing the power system. Time simulations are useful for detailed study of specific voltage collapse situations and coordination of protection and controls. The Dynamic Analysis module can be used for such time domain simulations. Many aspects of voltage stability problems can be effectively analyzed by using static methods, which examine the viability of the equilibrium point represented by a specified operating condition of the power system. The static analysis techniques allow examination of a wide range of system conditions, can provide much insight into the nature of the problem and can identify the key contributing factors. The Voltage Stability module contains 4 static methods: U-Q Sensitivity Analysis, Q-U Modal Analysis, U-Q Curves and P-U Curves. Static voltage stability analysis is based on the conventional load flow model.
U-Q Sensitivity Analysis U-Q sensitivity analysis calculates the relation between voltage change and reactive power change. ∆U = J R−1 ⋅ ∆Q ∆U
∆Q
JR
incremental change in bus voltage magnitude (vector) incremental change in bus reactive power injection (vector) reduced Jacobian matrix
The elements of the inverse of the reduced Jacobian matrix J R are the U-Q sensitivities. The diagonal components are the self sensitivities ∂U i / ∂Qi and the nondiagonal elements are the mutual sensitivities ∂U k / ∂Qi . The sensitivities of voltage controlled buses are equal to zero. Positive sensitivities: Stable operation; the smaller the sensitivity, the more stable the system. As stability decreases, the magnitude of the sensitivity increases, becoming infinite at the stability limit (maximum loadability).
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Voltage Stability
Negative sensitivities: Unstable operation. The system is not controllable, because all reactive power control devices are designed to operate satisfactorily when an increase in Q is accompanied by an increase in U.
Q-U Modal Analysis The modal analysis approach has the added advantage that it provides information regarding the mechanism of instability. Voltage stability characteristics of the system can be identified by computing the eigenvalues and eigenvectors of the reduced Jacobian matrix J R . JR = ξ ⋅ Λ ⋅ η Λ ξ
diagonal eigenvalue matrix right eigenvector matrix
η
left eigenvector matrix
ξi
ith right eigenvector, ith column of right eigenvector matrix
ηi
ith left eigenvector, ith row of left eigenvector matrix
Using modal analysis techniques the original problem (see chapter “U-Q Sensitivity Analysis”) ∆U = J R−1 ⋅ ∆Q
is transformed into u = Λ −1 ⋅ q u = η ⋅ ∆U
vector of modal voltage variations
q = η ⋅ ∆Q
vector of modal reactive power variations
The difference between these two equations is that Λ −1 is a diagonal matrix whereas the reduced Jacobian matrix in general is nondiagonal. The inverse transformation is given by ∆U = ξ ⋅ u ∆Q = ξ ⋅ q
Positive eigenvalue: The system is voltage stable. The smaller the magnitude, the closer the ith modal voltage is to being unstable. The magnitude of the eigenvalues can provide a relative measure of the proximity to instability. Zero eigenvalue: The ith modal voltage collapses because any change in that modal reactive power causes infinite change in the modal voltage. Negative eigenvalue: The system is voltage unstable.
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Voltage Stability
Eigenvalues and eigenvectors of the reduced Jacobian matrix for all practical purposes are real. If for “Buses without load elements” the option “Q=0, constant” is selected, ∆Q = 0 is introduced for buses without any active bus elements. In this case the variable ∆U of these buses is dependent only on other bus voltage magnitudes and is eliminated. Bus participation factors: The relative participation of a bus in a certain mode is given by the bus participation factor. Bus participation factors determine the areas with each mode. Thus, voltage weak areas or unstable (not controllable) areas are identified. The sum of all the bus participations for each mode is equal to unity. The size of bus participation in a given mode indicates the effectiveness of remedial actions applied at that bus in stabilizing that mode. Branch participation factors: The relative participation of branch j in a certain mode is given by the participation factor Pj =
∆Qloss j
[
max ∆Qloss j j
]
Branch participation factors indicate, for each mode, which branches consume the most reactive power in response to an incremental change in reactive load. Branches with high participations are either weak links or are heavily loaded. Branch participations are useful for identifying remedial measures to alleviate voltage stability problems and for contingency selection. Generator participation factors: The relative participation of machine m in a certain mode is given by the generator participation factor Pm =
∆Qm max[∆Qm ] m
Generator participation factors indicate, for each mode, which generators supply the most reactive power in response to an incremental change in system reactive loading. Generator participations provide important information regarding proper distribution of reactive reserves among all the machines in order to maintain an adequate voltage stability margin.
U-Q Curves The U-Q curves are produced by running a series of load flow cases. U-Q curves show the necessary amount of reactive power Q to achieve a specified voltage level U. The minimum point of a U-Q curve (reactive power injection positive) is the critical point, i.e. all points of the curve to the left of the minima are assumed to be unstable. The points to the right of the minima are assumed to be stable. If the minimum point of the U-Q curve is above the horizontal axis, the system is reactive power deficient. Additional infeed of reactive power is required to prevent
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Voltage Stability
voltage collapse. If the critical point is below the horizontal axis, the system has some VAR margin. Additional infeed of reactive power is required if a greater margin is desired. Voltage collapse starts at the weakest bus and then spreads out to other weak buses. Therefore the weakest bus is the most important in the voltage collapse analysis using U-Q curve techniques. The weakest bus is one that would exhibit one of the following conditions: a) has the highest voltage collapse point, b) has the lowest reactive power margin, c) has the greatest reactive power deficiency, or d) has the highest percentage change in voltage. Q
U
∆Q
Fig. 14.1 U-Q curve with VAR margin ∆Q
P-U Curves The P-U curves are produced by running a series of load flow cases. P-U curves relate bus voltages to load within a specified region. The benefits of this methodology are that it provides an indication of proximity to voltage collapse throughout a range of load levels. The nature of voltage collapse is that as power transfers into well-bounded region are increased, the voltage profile of that region will become lower and lower until a point of collapse is reached. The voltages at specific buses in the region can vary significantly, and some specific bus voltage could appear acceptable. The pointof-collapse at all buses in the study region, however, will occur at the same power import level, regardless of the specific bus voltages. U
P
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Voltage Stability
Fig. 14.2 P-U curve
Before the calculation can be run, the following has to be defined: • A set of loads to be scaled • A set of generators to be scaled • A set of bus voltages to be recorded • The load level at the beginning of the simulation • The load increment • The load level at the end of the simulation if the simulation should stop before the point-of-collapse occurs
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NEPLAN User's Guide V5
Small Signal Stability
Small Signal Stability Calculation Parameters To set the calculation options, select "Calculation - Small Signal Stability Parameters..." from the menu.
Calculation Eigenvectors
Enable calculation of eigenvectors
Participation factors
Enable calculation of participation factors
Limit for participation factors
Percentage of the maximum participation factor: participation factors greater than this value are stored. Set this value to 0 if all participation factors have to be stored.
Eigenvalue sort order
Determines the order how eigenvalues are listed in table and file outputs.
Eigenvalue interval
Eigenvalues located in this range are stored
Result Files File name
File name or full file path name
…
Select full path name
Build after calculation
File is automatically built after calculations
Build export file
File is built.
The small signal stability analysis can be started selecting "Calculation - Small Signal Stability - Calculation" from the menu. To perform small signal stability analysis for a partial network choose "Calculation - Small Signal Stability - Partial Network...".
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Small Signal Stability
Results
Graphical Results To open the graphical result window choose "Analysis – Small Signal Stability Graphical Results...". Subchart settings: Subchart type
Select results to be displayed
Axis properties Select axis
Select axis whose settings have to be displayed / changed.
Title
Axis title. Only enabled if the corresponding check box “Automatic” is not checked.
Resolution
Specifies the resolution of the steps in between labels. Only enabled if the corresponding check box “Automatic” is not checked.
No of digits
Number of label digits. Only enabled if the corresponding check box “Automatic” is not checked.
Min
Sets the axis minimum value. Only enabled if the corresponding check box “Automatic” is not checked.
Max
Sets the axis maximum value. Only enabled if the corresponding check box “Automatic” is not checked.
Grid
If checked grid lines are displayed.
Legend Show legend
If checked, legend will be displayed
Height
Height of legend in % of subchart size
Choose the tab “Curves” in order to add or edit curves. Press the “Add Curve” button to add a new curve to the subchart. Press the “Edit Curve” button to change the settings of the selected curve. Curve settings: Curve name
Curve name used for the subchart legend. This field is enabled only if “Create name automatically” is not checked.
Create name
If checked, curve name is automatically created
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Small Signal Stability
automatically Variant
Select variant
Eigenvalue
Select eigenvalue. Enabled only for mode shape charts and eigenvalue participation factor charts.
State variable
Select state variable. Enabled only for state variable participation factor charts
Result Tables To open the result tables choose "Analysis – Small Signal Stability – Result Tables". The result tables display all calculated and stored numerical results.
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15-3
Small Signal Stability
Theory
Introduction Small signal stability is the ability of a power system to maintain synchronism when subjected to small disturbances. Disturbances are said to be small if the equations that describe the resulting response of the system may be linearized for the purpose of analysis. The linear equations are derived from the corresponding nonlinear equations. That is done trough linearization at a specified operating point. An operating point corresponds to a steady-state load flow condition. Eigenvalue analysis (modal analysis) is a valuable tool in analysis of power system small signal stability. It provides information about the inherent dynamic characteristic of the power system and assists in its design. It is typically used in studies of interarea oscillations. Eigenvalue Theory The linearized state space equations of a nonlinear system are ∆x& = A ⋅ ∆x + B ⋅ ∆u ∆y = C ⋅ ∆x + D ⋅ ∆u
The stability in the small is given by the eigenvalues λi of the state matrix A . For any eigenvalue λi , there exists at least one nonzero column vector ri which satisfies A ⋅ ri = λi ⋅ ri
The vector ri is called a right eigenvector of its eigenvalue λi . A vector li which satisfies AT ⋅ li = λi ⋅ l i
is called a left eigenvector of its eigenvalue λi . The stability of a power system is determined by the eigenvalues as follows: A real eigenvalue corresponds to a non-oscillatory mode. A negative real eigenvalue represents a decaying mode. The larger its magnitude, the faster the decay. A positive real eigenvalue represents aperiodic instability.
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Small Signal Stability
Complex eigenvalues occur in conjugate pairs (since the state matrix is real), and each pair correspond to an oscillatory mode. The real component of the eigenvalues gives the damping, and the imaginary component gives the frequency of oscillation. A negative real part represents a damped oscillation whereas a positive real part represents oscillation of increasing amplitude. For a complex pair of eigenvalues λ = σ ± jω the frequency of oscillation in Hz is given by f =
ω 2π
The damping ratio is given by ζ =
−σ
σ 2 +ω2
Mode shape A right eigenvector gives the mode shape, i.e., the relative activity of the state variables when a particular mode is excited. For example, the degree of activity of the state variable xk in the ith mode is given by the element k of the right eigenvector ri . The magnitudes of the elements of ri give the extents of the activities of the state variables in the ith mode, and the angles of the elements give phase displacements of the state variables with regard to the mode. Because different system variables have different units, it is inconvenient to compare elements of an eigenvector for different types of variables. Generally, only variables of a same type (e.g rotor speed) are compared. Participation factor For the kth state variable and the ith eigenvalue, the associated participation factor is calculated by pki = lki ⋅ rki
where lki and rki are the kth entries in left eigenvector li and right eigenvector ri respectively. A participation factor is a measure of the relative participation of the kth state variable in the ith mode, and vice versa. Since rki measures the activity of the state variable k in the ith mode and lki weighs the contribution of this activity to the mode, the product measures the net participation.The effect of multiplying the elements of the left and right eigenvectors is also to make the participation factor dimensionless (i.e. independent of the choice of units).
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Small Signal Stability
In view of the eigenvector normalization, the sum of the participation factors associated with any eigenvalue or with any state variable is equal to 1.0 + j 0.0: n
∑ pki = 1 + j0 k =1 n
∑ pki = 1 + j0 i =1
Participation factors are complex values. However, their magnitudes provide enough information for dynamic system analysis. Algorithm The NEPLAN small signal stability calculation procedure contains the following main steps: 1. 2. 3. 4. 5.
Load flow calculation Linearization of the state space equations of all power system elements (e.g. generators, loads, etc.) Build system state matrix A . Calculation of eigenvalues and eigenvectors using an LR-QR algorithm Calculation of participation factors, etc.
Results are only available if no error occurred.
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Transient Stability
Transient Stability General Remarks Transient Stability module is a simulation program for computing electromechanical transient phenomena in electricity networks. For calculating the electricity network's behavior, all network elements are simulated by mathematical models. Synchronous machines and their control circuits are described (in terms of their behavior in non-steady-state operation) by their system equations, which contain algebraic equations and differential equations. In conjunction with the algebraic equations of the network, we thus obtain an equation system representing a mathematical model of the entire network. In addition to the depiction of the primary elements, the Transient Stability module also provides an option for simulating secondary elements (protective equipment). During the simulation process, the measured values of the protective relays are determined and the trip conditions are continuously monitored. Trips, and the associated switching operations, are performed automatically by the program. Adjustment and monitoring routines for complex protective systems are thus significantly facilitated. The starting point for each simulation is a steady-state operating condition, which is determined by a load flow calculation beforehand.
Simulation method The simulation method's job in calculating electro-mechanical transient phenomena is to simultaneously solve the algebraic equations of the network and the system equations of the dynamic elements at any one point in time. The algebraic equations of the network are the model equations of the quasisteady-state elements in the electricity network. These elements are: lines, transformers, constant compensators, and loads with constant impedance. The model equations are formed from complex admittances and/or admittance matrices. The model equations for the individual quasi-steady-state elements are put together to form the network admittance matrix YN so as to reflect the network topology. The network admittance matrix is a square matrix with complex matrix elements, with the order of the matrix corresponding to the number of nodes in the network. The matrix equation of the electricity network is thus obtained as −1
u = YN ⋅ i
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Transient Stability
If the node currents i are known, then the unknown node voltages u can be calculated. During simulation, the network admittance matrix is constant for as long as there are no changes to the topology. The network admittance matrix is altered only by switching operations in response to network disturbances, or in the event of tripping of faults. The inverse of YN is determined by factorizing, and to minimize the computation work the sequence of the nodes is specified by dynamic ordering. The incoming node currents i are the output variables for the system equations of the dynamic elements and are mostly voltage-dependent. Node currents are also caused by loads which do not represent an impedance pure and simple. These node currents, too, are voltage-dependent. The matrix equation of the electricity network is thus non-linear and has to be solved iteratively. System equations are used for all pieces of equipment which are simulated by algebraic and differential equations. The system equations generally read in the state form
dx = A ⋅ x + B ⋅u dt y = C ⋅ x + D ⋅u
As exemplified by the model of the synchronous machine, the input variables u are the d and q axis components of the terminal voltage, the excitation voltage and the turbine's torque. The output variables y are the terminal currents. The current feeding into the inverted network admittance matrix can be determined by transformation from the fixed-rotor coordinate system into the complex coordinate system of the network equations. The state variables x depend on the model selected, and do not have to correspond to physical variables. Laplace transformation of the differential equations of the system equations will produce the following: X(s) = (sI - A)-1·x0 + (sI - A)-1·B·U(s) A and B are given, x0 is the starting point of the state variables. If the input variables U(s) were also known, then re-transformation into the time domain would produce an accurate solution of the state equations. If the input variables are approximated between two integration points by means of a first-order polynomial (straight line), the following integration formulas are obtained (see [1])
xn+1 = P·xn + W1·un + W2·un+1 ... Variables at the beginning of the integration interval xn,un 22-2
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Transient Stability
xn+1,un+1 ...
Variables at the end of the integration interval
The integration method is an implicit single-step method, and is stable for all integration step sizes, irrespective of the sizes of the time constants involved. The integration formula contains one part, which depends only on the variables at the beginning of the interval. This part must be calculated only once per interval, and is then constant during the iterative solution process. The input variables u at the end of the integration interval are estimated at the beginning of the iteration and then continuously improved as iteration proceeds. The coefficient matrices P, W1 and W2 are constant for as long as the integration interval remains unchanged. The coefficient matrices are determined analytically, or by series development, in dependence on the size and the structure of system matrix A. To avoid excessive computation work, the system equations are divided into subsystems, with an order of up to three or four. The subsystems are then solved consecutively, block by block, thus arriving at a solution to the entirety of all system equations within the iterative solution process. The iterative solution process looks like this: a) Start with initial load flow or with the result of the last integration step, estimate the input variables for the end of the interval. b) Solve the system equations for the dynamic elements and for loads not representing a constant impedance. Determine the incoming currents I. c) Solve the network equations and calculate the new node voltages d) Check the convergence by comparing the node voltages prior to and after iteration. When convergence has been reached, iteration will be aborted and the next integration interval started. Otherwise continue with iteration at b). This iterative solution of the network equations and system equations will supply a simultaneous solution for the entire system without any interface error. A control function for the integration's step size is superimposed onto the iteration process described above. The step size is changed in dependence on the deviation between the estimated and the actually computed variables for rotor angle and electric active power of synchronous machines. A logic function increases or decreases the step size between specified values. Thanks to this step-width control, the computation work required for a long simulation period can be significantly reduced.
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Transient Stability
Terms and Definitions, Per-Unit System
Terms and Definitions Function block A function block is the smallest function unit of a control circuit. Each function block is described by a transfer function, which forms the output signal(s) from the input signals. A transfer function can be independent of time (algebraic equations only) or dependent on time (algebraic and differential equations). Variable An variable is the analog or binary output variable of a network element which varies in time. A variable can be selected for outputting and display, or can serve as input variable for a control circuit or a protective device. The user can change a variable's value by forming absolute values, by negation and/or inversion. Controller signal A controller signal is an analog or binary output of a function block of a control circuit. A controller signal is available as a variable both within the control circuit concerned and outside it as well. Switching operation A switching operation is a change in the state of a network element. There is more than one type of switching operation for each type of element. A switching operation is triggered at a preset point in time by the user or automatically by the trigger function of a protective device.
Per-Unit System Internally, the Transient Stability module calculates with referenced variables, with per-unit variables. The nominal values of the network elements are converted into "per-unit" with the reference power SB and with the reference voltage UB which is specified for each node. Reference power and reference voltages are read in using the LoadFlowFile. Referenced powers Nominal values:
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S[ MVA ] = P[MW] + j ⋅ Q[ MVAr ] Per-unit:
s = p + j⋅ q
⇔
S P Q = + j⋅ SB SB SB
Referenced voltages Nominal values:
U[ kV ] = U re [kV] + j ⋅ U im [kV] Per-unit:
u = u re + j ⋅ u im
⇔
U U re U = + j ⋅ im UB UB UB
Referenced currents Nominal values:
Reference current:
I[ A ] = I re [A] + j ⋅ I im [ A ]
IB =
SB 3 ⋅ UB
Per-unit:
i = i re + j ⋅ i im
⇔
Referenced impedances Nominal values:
Z[Ω ] = R[Ω] + j ⋅ X[Ω]
I I I = re + j ⋅ im IB IB IB
Reference impedance:
ZB
U 2B = SB
Per-unit:
z = r + j⋅ x
NEPLAN User's Guide V5
⇔
Z R X = + j⋅ ZB ZB ZB
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Transient Stability
Referenced exciter voltages The voltages of the synchronous-machine models are referenced variables with the reference network voltage UB of the machine terminal's node as the reference variable. In order to simulate exciter devices, the exciter voltage and the input variables of the voltage controller model must be converted from network-per-unit into exciter-per-unit. In accordance with IEEE [4], the reference variable UE for exciter voltages is that exciter voltage which in no-load mode produces rated voltage at the machine terminals on the synchronous machine. Network-per-unit and exciter-per-unit are different only if the saturation of the synchronous machine is simulated or if the synchronous machine's rated voltage UN is not equal to the reference voltage UB. Network-per-unit:
Conversion factor:
ufB
UB UB = UE U N ⋅ 1 + A ⋅ e 0,2⋅B
(
)
A,B ... saturation factors (see synchronous machines)
Exciter-per-unit: ufE
22-6
⇔
u fE = u fB ⋅
(
UB
U N ⋅ 1 + A ⋅ e 0,2⋅B
)
NEPLAN User's Guide V5
Transient Stability
Network Elements
Controlled Admittance Controlled admittances are the most general form of a simulation model in the Transient Stability module. Controlled admittances in combination with controller models of any desired structure give users complete freedom to choose the nature and complexity of the mathematical model to be simulated. Basically, a controlled admittance is a constant admittance ycad, which has been permanently incorporated in the network admittance matrix. The constant admittance's value is entered through Dynamic Data file, and is independent of the value of the admittance in the initial load flow. The effective admittance is generated by an injected current into the admittance matrix. The effective admittance (in [Ohm-1]) can be controlled by any desired controller model. Active and reactive components of the admittance can be controlled independently of each other. A controlled admittance is primarily intended for modeling static reactive power compensators. In these cases, it is only the reactive component that is controlled, the active component (if it does not equal 0) remains unchanged. The controlled admittance corresponds to the "Interface" block of Fig. 11.67 in [7]. However, controlled admittances can also be used to model (above and beyond static compensators) dynamic load models, special synchronous-machine models and the like. The use of controlled admittances requires a good knowledge of the effect of the admittance concerned and of the supply current on the solution of the network equations. Since plausibility checks are not run, divergence or numerical instability can easily be achieved! Block diagram of the simulation model G
SB
ycad
2
UB
uk Iterations
B
SB 2
UB
uk j
y
Π
ik
icad ycad
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Transient Stability
Variables All variables of a controlled admittance are analog variables. A… Voltage magnitude [pu] B… Voltage angle [degree] C… Current magnitude [A] D… Current angle [degree] E… Active power [MW] F… Reactive power [MVAr] G… Magnitude of the effective admittance [Ohm-1] H… Angle of the effective admittance [degree] I… Active component of the effective admittance [Ohm-1] J… Reactive component of the effective admittance [Ohm-1] Switching operations none Function Generators A function generator is a fictitious network element, serving to test control equipment or as a disturbance function for network simulation. A function generator is switched on and off by means of a switching operation. More than one function generator can be switched on simultaneously. The following types of function generators are available:
A .... Step If the generator is switched off, the output signal is 0. If the generator is switched on at the time t0, the output signal equals the constant value K. B .... Ramp If the generator is switched off, the output signal is 0. If the generator is switched on at the time t0, the output signal is computed, using the function . 22-8
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K y = Min K , ⋅ ( t − t 0 ) T If |T| < 0.0001, the ramp function corresponds to a jump function of the size K.
C .... Sine If the generator is switched off, the output signal is 0. If the generator is switched on at the time t0, the output signal is computed, using the function
2π y = K ⋅ sin ⋅ t − t 0 + Tϕ . T
(
)
If |T| < 0.0001, the sine function corresponds to a jump function of the size K. Variables A .... Output of the function generator [pu] Switching operations A .... Generator ON Parameters: none The function generator is switched on. B .... Generator OFF Parameters: none The function generator is switched off.
Simulation The simulation sequence can be controlled in dependence on the computed results using a fictitious network element called "Simulation". Variables None Switching operations A Abort simulation Parameter: none NEPLAN User's Guide V5
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Transient Stability
The switching operation aborts the simulation immediately. B Set debug flag Parameter: P1 Number of debug flag[#] Debug flag Number P1 is set, and the debug information concerned is output. The debug flag remains set until it is reset again. If the debug flag had not been set, the switching operation has no function. C Reset debug flag Parameter: P1 Number of debug flag [#] Debug flag Number P1 is reset. If the debug flag had not been set, the switching operation has no function.
Maximum-minimum relays Maximum-minimum relays monitor a measured variable for over or under violation of a preset measured value. If the measured variable of a maximum relay exceeds the threshold value (Starting), a time counter is started, which defines a time interval. If the measured variable concerned remains above the threshold value during this time interval, then a trip command will be output at the end of the interval. If the measured variable falls back below the threshold value, the time counter will be reset, and no trip command will be output. If a trip command is given, the associated trip function will be executed on expiry of a breaker opening time. Examples of maximum-minimum relays are - overcurrent relays - overvoltage relays - undervoltage relays - power relays - impedance relays (central impedance circuit) - frequency relays The concept of a monitored measured variable is not restricted to the measured variables listed above. Any variable can be used as monitored measured variable. Up to four relay stages can be operated by one measured variable. Any desired switching operation can be triggered as a trip function assigned to a relay stage. More than one trip function can be assigned to one relay stage. Starting or trip signals can be utilized as signal connections for other relays. The monitoring of specific variables can advantageously be utilized for controlling the simulation run. To determine the stability limits, for example, the rotor angle
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Transient Stability
can be monitored. If a defined value is exceeded, then the simulation will be aborted as the "switching operation" of the relay. The generator will then already have fallen out of synchronism, and the computation can be aborted. Variables All variables of max/min relays are binary variables. A Trip, Stage 1 B Trip, Stage 2 C Trip, Stage 3 D Trip, Stage 4 Switching operations None
Distance protection The simulation model for distance protection equipment processes analog and binary input signals, and sends out binary output signals. The signal flow plan is shown on Page 15.
x
r
The analog input signals are current and voltage of the branch element assigned. Additionally, and independent of all subsequent functions, the current is monitored for over violation of a minimum value and the voltage for under violation of a maximum value. If there is no over or under violation, none of the subsequent time counters will be started. In the "direction" block, the direction of the fault is determined from current and voltage. If the measured impedance in the r/x diagram is in the hatched area (see picture on right), then the decision will be for forward direction. Otherwise, it is a case of backward direction. The effect of the direction can be set as positive, negative or inoperative both for starting and for the measuring stages. This means NEPLAN User's Guide V5
22-11
Transient Stability
characteristics can be simulated as forward-directional, backward-directional or non-directional. In the "Starting" and "Measurement" blocks, tripping of the distance relay or the start of a time counter for a measuring stage is derived by means of impedance characteristics, which can be used for the following functions: - Starting - Stage 1 - Stage 1 extended - Stage 2 - Stage 3 - Trip and triggering of an external auto-reclosure Each of these functions can be associated with the following impedance characteristics. More than one characteristic of the same type or different types can be associated with one function. Overcurrent starting The use of overcurrent starting is predominantly intended for the "Starting" function. The overcurrent starting function evaluates only the current of the branch element, and is voltage-independent. It is thus an "impedance characteristic" only in a very general sense. If the current of the branch element exceeds the minimum-current value, the time counter of the function assigned will be started. Circular characteristic The circular characteristic in the r/x diagram is shown in the adjacent picture. If the impedance point measured is located inside the circle, then the associated time counter will be started. The circle has a diameter of Z, and is offset from the coordinate center by (R,X).
Polygonal characteristic The polygonal characteristic in the r/x diagram is shown in the adjacent picture. If the impedance (R2,X2) point measured is located inside the polygon, then the associated time counter will be started.
x Z R
x
X
r
(R3,X3)
r
The polygon is defined by four corner points. If the fourth corner point is not specified, the poly(R4,X4) (R1,X1) 22-12
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Transient Stability
gon will be interpreted as a triangle. Polygons with more than 4 corner points can be created by combining several 4-cornered polygons. Binary signals Binary signals can be used to influence the behavior of the distance protection model by external events. The binary input signals can be binary output signals from other distance relays or from other types of relays as well. These signals can be altered both at the signal source and at the input of the distance relay. For controlling the time dependent signal flow, binary signals can be provided at the source with a pick-up delay TAS and/or with a drop-out delay TAF. For the time of signal transmission between the signal source and the destination, the signal can be assigned a transmission time TL.
Signal source TAS
Pick-up delay TAF TL
Drop-out delay Transmission time
The illustration above shows the basic manner in which the signal is influenced. When the signal arrives at the distance relay, it can be altered as follows: 0 1 2 3
Signal is not altered Signal is inverted Signal is always 1 Signal is always 0
Note that a binary signal can have the following functions in the distance protection model (see illustration at the end of this chapter): Blocking A trip command to the circuit-breaker will be given only when this signal is not being received. Enable The time counter of Stage 1 will not be started until the external signal is being received. The start of Stage 1 time counter will, however, be blocked only until the time, TFG, has elapsed. On expiry of
NEPLAN User's Guide V5
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Transient Stability
TFG, Stage 1 time counter will be started even if no enable signal is being received. Intertripping If a signal is being received, a trip command will be sent provided that the directional starting has been activated. Range extension When an external signal is being received, the Stage 1 extended is activated. External starting Starting function begins when an external signal is being received. Auto-reclosure blocking The time counter for a trip using the characteristic for auto-reclosure will be started only when no external signal is being received. Variables All variables of the distance relay are binary variables. B General starting C Directional starting D General tripping E Tripping, Stage 1 F Tripping, Stage 1 extended G Tripping, Stage 2 H Tripping, Stage 3 I Tripping, directional starting J Tripping, non-directional starting K OFF command (signal to circuit breaker) L Forward direction M Auto-reclosure Switching operations None
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Transient Stability
Signal flow plan for distance protection External starting
1
≥1
I> & U<
TAU
&
9
& 2
&
TAG
&
8
1
1
T3
&
Starting
7
6
T2
T1E
≥1
3
≥1
&
&
10
TLS
Circuit-breaker opened
5
&
11 Direction
T1
4
& &
Auto-reclosure blocking TWE
WE
Current
12
&
&
3 Messung
Voltage
2 Internal Signals: 1E
1
&
TFG
Range extension Enable Intertripping Blocking
&
≥1
1 .....General starting 2 .....Directional starting 3 .....General tripping 4 .....Tripping Stage 1 5 .....Tripping Stage 1 extended 6 .....Tripping Stage 2 7 .....Tripping Stage 3 8 .....Tripping directional starting 9 .....Tripping non-directional starting 10 ....OFF command 11 ....Forward direction 12 ....Auto-reclosure
Pole slip protection Pole slip is a dynamic, asynchronous operation of two or more synchronous generators, in which the air-gap voltages of the generators run at least once through phase opposition.
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Transient Stability
x ZA ZC α
ϕ
r
ZB
In the event of a short-circuit in the network, a generator is relieved of active power and accelerated, because the turbine torque does not change immediately. If the short-circuit is of short duration, the generator will indeed exhibit power swing in relation to the network, but the oscillation will decay under damping. If the short-circuit duration exceeds a certain value, which will depend on generator capacity utilization, the type of fault concerned, and how far away it is, the generator will pull out of synchronism, exhibiting slip against the network. Pulling out of synchronism is accompanied by major oscillations in current and power, and constitutes a severe stress case for the generator involved. In order to avoid mechanical and thermal damage, a slip must be detected as soon as possible, and the generator disconnected from the network. In a network with more than one generator, the slip can be acquired using the movement of the impedance pointer, viewed from the generator terminals, in the r/x plane. The characteristic of the pole slip current in the Transient Stability module consists of a lens-shaped area divided into two lens halves by a straight line in the lens axis. A straight line which is aligned perpendicular to the lens axis will divide the r/x plane into areas close to and remote from the generator terminals. The coordinate center designates the generator terminals. The position of the lens is defined by the angle phi of the lens axis, and the shape of the lens by the angle alpha. The criterion for a slip is the movement of the impedance pointer through the lens. The impedance pointer must enter into the lens area on one side, and exit from the lens again on the other side. The impedance pointer must dwell for at least 25 ms in each half of the lens. If the impedance pointer passes through the lens above the straight line, this means the slip concerned is remote from the generator terminals, and in Stage 2, otherwise it is close to the generator terminals, and in Stage 1. The maximum acquirable slip frequency is specified by selecting the lens size and the lens shape. The wider the lens is, the higher the slip frequencies are which can be detected. The width of the lens, together with the lens size, also determines the range in the r-direction, which must exhibit a sufficiently large distance from the minimum operating impedance.
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The relay's trip function can be specified separately for Stage 1 and Stage 2. More than one trip function can be defined for each level. Any switching operation can be assigned as the trip function. For a description of the trip functions, see under "Maximum-minimum relays". Variables All variables of the pole slip relay are binary variables. A Trip, Stage 1 B Trip, Stage 2 Switching operations None
Overcurrent protection Functional description In electricity networks, an overcurrent protection feature monitors a measured current, and sends a trip command to a circuit-breaker when the current meets defined starting and trip conditions. Simulation of an overcurrent protection feature in the Transient Stability module is accordingly divided up into • measured variable • starting condition • trip condition • trip function An overcurrent protection feature possesses a measured variable, a starting condition and a trip function. An overcurrent protection feature can, however, have more than one trip condition (e.g. independently time-delayed high-current level, dependently time-delayed overcurrent level). Measured variable The measured variable can be a current magnitude from any network element. Other variables are not permissible (error message). Starting condition The starting condition is the over violation of a starting current IA, which is the multiple KA of the set current IE. After starting, the trip time begins to run (trip condi-
NEPLAN User's Guide V5
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Transient Stability
tion). If the current drops below a reset current IR (which is the multiple KR of the set current IE), before the trip time has elapsed, the trip time will be reset and no trip will be executed.
IA = K A ⋅ IE IR = K R ⋅ IE Trip condition Different characteristics can be selected for the trip time, as the trip condition. An overcurrent protection feature can be associated with more than one trip characteristic. 1) Independent trip time The trip time tA is constant, and independent of the current measured:
t A = TE 2) Analytically dependent trip time The trip time tA is variable, and depends non-linearly on the measured current I. The non-linear correlation is analytically given as,
tA K1 = TE I K − 1 IE 2
By means of K1 and K2, the trip characteristics can, for example, be formed in accordance with IEC 255: Normally dependent (Type A) : Heavily dependent (Type B) : Extremely dependent (Type C) :
K1 = 0.14 K1 = 13,5 K1 = 80
K2 = 0.02 K2 = 1 K2 = 2
If the current is more than the multiple KB of the set current IE, the trip time will not be reduced any
I = K B ). KB is, for example, equal to 20. I E
further; ( max
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3) Tabularly dependent trip time The trip time tA is variable, and is non-linearly dependent on the current I. The non-linear correlation is given as a tabular function:
tA = f I TE I E
A tabular function can, for example, be used to simulate fuse characteristics. Trip function If the measured current remains above the reset current IR longer than the trip time after the starting current IA has been exceeded, the trip function will be initiated. In the Transient Stability module, the trip function is any desired switching operation. More than one switching operation, can also be assigned to a single trip function. On expiry of a breaker opening time which can be set for each switching operation, the switching operations will be executed. Variables The variables of an overcurrent relay are analog or binary variables. A Measured current I [A] B Effective trip time tA [s] C Starting condition fulfilled [binary] D Trip condition fulfilled [binary] Switching operations No switching operations can be performed at an overcurrent protection feature. This must NOT be confused with switching operations which are caused by an overcurrent protection feature. Pickup Conditions Subroutine REGS gives as currents the square of per unit currents: I i = IB
2
2
IB
current base of network element
SB 3 ⋅ UB
Pickup condition in nominal values is I > IA
⇒ I2 > I2A
⇒ i2 ⋅ IB2 > (K A ⋅ IE )
2
Results as programmed pickup condition:
NEPLAN User's Guide V5
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Transient Stability
K ⋅I i2 > A E IB
2
⇒ i2 > pcka
where 2
K ⋅I ⋅U K ⋅I pcka = A E = 3 ⋅ A E B SB IB
2
Analytical Dependent Time Delay Characteristics Subroutine REGS gives as currents the square of per-unit currents (see above). The characteristic requires 1
2 2 I i ⋅ IB 2 IB = = i ⋅ IE IE IE
The analytical characteristic results as
tA = TE
K1 K2 2 2
I i2 ⋅ B IE
= −1
(i
tck1 2
⋅ pcie
)
tck 2
−1
where 2
I 1 SB pcie = B = ⋅ 3 IE ⋅ UB IE
2
tck1 = K1
tck2 =
22-20
K2 2
NEPLAN User's Guide V5
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Program control
Simulation run and table output Initial integration step length The simulation is started with the initial step length, and altered automatically by the program. If the step length control has been switched off, then the entire simulation will be executed with the integration step length, XDT0. Default value: 0.001 s (when XDT0 < 0.0001 s) Simulation duration Default value: XDT0 (when TEND < XTD0) Automatic step length control 0 switched off 1 switched on Default value: 1 (when NVIS ≠ 0) Name of a synchronous machine for reference rotor angle The rotor angle of the synchronous machine with this name is the reference variable for outputting the rotor angles of all other synchronous machines. All rotor angles are output as the difference from the rotor angle of the reference synchronous machine. Controlling program run stop 0 No stop 1 Stop after reading in load flow 2 Stop after reading in and initializing the dynamic data 3 Stop after reading in and initializing the protective data 4 Stop after reading in all data Default value: 0 (when NST < 0 or > 4) Control of list outputs of variables 0 Lists are not printed 1 Lists are printed Default value: 1 (when KLIS ≠ 0)
NEPLAN User's Guide V5
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Transient Stability
Control of output of variables on file 0 Variables are not output 1 Variables are output Default value: 1 (when KMON ≠ 0) Number of points per variable on file It states only the approximate number of points per variable. Due to switching operations and step length control, the actual number may deviate from that specified. Default value: 150 (when NVF < 1)
Simulation parameters Number of sub-intervals for control circuits The system equations for the control circuits are solved NSI times within one integration step. Minimum value is 2. Default value: 5 (when NSI < 2 or > 100) Maximum number of iterations for the implicit solution Default value: 100 (when NITAMX < 1 or > 1000) Convergence tolerance for active power of synchronous machines Default value: 0.001 per unit (when EPSP < 10-8 or > 0.1) Convergence tolerance for real and imaginary components of node voltages Default value: 0.001 per unit (when EPSV < 10-8 or > 0.1) Limitation of the table for multiplication of the initial step length The integration step length is altered in multiples of the initial step length. Multiplication proceeds in accordance with the table given below. The maximum step length can be specified by limiting the table. 1 1 5 15 9 35 13 55 17 75 2 2 6 20 10 40 14 60 18 80 3 5 7 25 11 45 15 65 19 85 4 10 8 30 12 50 16 70 20 90 Default value: 20 (when NVIMMX < 1 or > 20) Maximum number of iterations for the implicit solution after which the step length to be reduced 22-22
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Default value: 7 (when NVIIMX < 1 or > 20) Number of steps to further increase the step length after the last increase of the step length Default value: 3 (when NVIINC < 1 or > 20) Number of steps to increase the step length after the last decrease of the step length Default value: 10 (when NVIDEC < 1 or > 20) Maximum active-power mismatch to increase the step length Default value: 0.001 per unit (when DEPEMX 0.1) Maximum frequency mismatch to increase the step length Default value: 0.001 rad/s (when DERSMX < 10-6 or > 0.1)
NEPLAN User's Guide V5
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Symbol Library
Symbol Library Overview With the NEPLAN Symbol Library you can • modify the existing element and protection device symbols, • add new element and protection device symbols, using existing symbols as a template, • draw your own graphic symbols.
Basic Concepts The symbols can be categorized to the following groups: 1. Symbols of network elements with one or more connecting points to nodes (loads, transformers, etc.), 2. Symbols of protection devices and switches (relays, earthing switches, etc.) 3. Symbols for "General Elements" 4. Disconnection Symbol and Flow Indicator 5. Drawing Symbols In the main application you can select the network and the protection device symbols with "Input - Symbol Selection". To draw a "drawing symbol" you have to select "Draw - Symbol...". Select the symbols for the disconnection symbol and flow indicator with "Options Symbols".
Symbols of Network Elements Symbols of network elements are drawn between their connecting points (Fig. 17.1). To each graphic object of the symbol, you can assign a connection side. This side will be considered, if you color the network according to the voltage levels. For switchable symbols you get two diagrams, one for the "ON" state and the other for the "OFF" state.
NEPLAN User's Guide V5
17-1
Symbol Library
Connecting Point
Fig. 17.1 Symbols of network elements
Symbols of Protection Devices and Switches Protection devices are positioned at the logical switches of an element and are connected to the corresponding node. The connecting point of a protection device determines the distance from the node (Fig. 17.2).
Fig. 17.2 Protection Devices and Switches
Symbols for "General Elements" The general element type, can be used for documentation and information purposes. These elements will not be used for the calculation. New general element types can be defined with the Symbol Library. For each element type it is possible to assign a SQL database table (requires the optional SQL database driver module). The fields of this SQL table can be defined by the user.
Disconnection Symbol and Flow Indicator You can define your own symbols for the disconnection symbol and flow indicator. The connecting point of the disconnection symbol determines the distance from 17-2
NEPLAN User's Guide V5
Symbol Library
the node. The disconnection symbol will be shown, if the display of the "logical switches" is not selected (see "Drawing parameters").
Drawing Symbols The drawing symbols are not connected to any other element. They can be scaled in the main application.
Mouse Buttons
Select Mode Pressing the left mouse button selects and deselects the graphic objects. Holding down the "Shift-key" allows multiple selection. Press the left mouse button while moving the mouse to move selected objects.
Drawing Mode To enter new objects press the left mouse button while moving the mouse.
Double-Click A double-click on an objects brings up the property dialog box.
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Symbol Library
Graphical Elements
Line Width (Symbol Library) The line widths of the different symbols are considered as follows: Network elements, Protection Devices
If the line width is set to 0.0 mm, the setting for the corresponding element of the main application are taken into consideration for the line width. Line widths > 0.0 mm will be taken into consideration by the main application.
"General Element", Disconnection symbol, Flow indicator, Drawing symbols
If the line width is set to 0.0 mm, the main application sets the line width to 1 pixel (∼0.25 mm). Line widths > 0.0 mm will be taken into consideration by the main application.
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References
References Additional References
/1/
L. Busarello Über die Entwicklung eines Programmsystems zur Analyse und Planung elektrischer Energieversorgungsnetze für Arbeitsplatzcomputer Dissertation Nr. 8319, Eidgenössische Technische Hochschule Zürich, 1987
/2/
VDE0102 Teil 100 Berechnung von Kurzschlussströmen in Drehstromnetzen Entwurf April 1985, VDE-Verlag, D-Berlin 12
/3/
H. Happolt, D. Oeding Elektrische Kraftwerke und Netze Springer-Verlag
/4/
O. I. Elgerd Electric Energy System Theory. An Introduction McGraw-Hill, 1971
/5/
Elektrische Energietechnik, Bände 1-3 Springer-Verlag, 29. Auflage, 1988
/6/
L. Busarello, G. Balzer, K. Reichert Die Kurzschlussstromberechnung nach IEC 909 SEV-Bulletin, Heft 9, 1989
/7 /
Xiao-Ping Zhang Fast three phase load flow method IEEE Transaction on Power Systems, Vol. 11, No. 3. August 1996
/8 /
Funk, Hantel Frequenzabhängigkeit der Betriebsmittel von Drehstromnetzen ETZ-Archiv Band 9 (1987), Heft 11, Seiten 349-356
/9/
W. Tenschert Simulation elektromechanischer Ausgleichsvorgänge in elektrischen Energienetzen mit Nachbildung von Schutzeinrichtungen. Dissertation Technische Universität Wien, 1988
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References
/ 10 /
I.M. Canay Determination of model parameters of synchronous machines. IEE Proc., Vol.130, Pt.B., 1983, H.2, S.86-94
/ 11 /
Polschlupfschutz GZX 104 - Technische Beschreibung. BBC, CH-ES 31-58 D
/ 12 /
Excitation System Models for power system stability studies. IEEE Committee Report IEEE Transactions, Vol. PAS-100, 1981, S.494-509
/ 13 /
P.M. Anderson, A.A. Fouad Power System Control and Stability The Iowa State University Press, 1977
/ 14 /
S. Ertem, Y. Baghzouz Simulation of Induction Machinery for Power System Studies IEEE Transactions on Energy Conversion, Vol.4, 1989, S.88-94
/ 15 /
P. Kundur Power System Stability and Control EPRI Power System Engineering Series McGraw-Hill, Inc.
/ 16 /
G. Hosemann (Hrsg.) Hütte - Taschenbücher der Technik; Band3: Netze Springer Verlag, Berlin, 1987 ISBN 3-540-15359-4
/ 17 /
H.-J. Haubrich (Hrsg.) Zuverlässigkeitsberechnung von Verteilungsnetzen. 1. Auflage, Aachen, Verlag der Augustinus-Buchhandlung1996 (Aachener Beiträge zur Energieversorgung, Bd. 36) ISBN 3-86073-492-X
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Appendix The Structure of the Import-/Export-Files
EDT-File With the help of the EDT-file, topological and electrical data can be imported and exported. This File can be generated and read by MS-Excel (see "Interfaces to NEPLAN - Import/Export" in chapter "Tutorial" and "File - Import/Export" in chapter "Menu Options"). When exporting the file, the user will be asked about the field seperator to use in the EDT-file. The structure and the description of the file are found below:
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---------------------------------------------------------------------------| Data field| Elements | |--------------------------------------------------------------------------| |Name |Type | Line |Coupling|Reactor |2-w.Tran|3-w.Tran|Shunt |Net.feed| |--------------------------------------------------------------------------| | id | N2 | [1] | [2] | [3] | [4] | [5] | [50] | [51] | | l1 | L |Switch 1|Switch 1|Switch 1|Switch 1|Switch 1|Switch 1|Switch 1| | l2 | L |Switch 2| |Switch 2|Switch 2|Switch 2| regul ?| | | l3 | L | | | |regulate|Switch 3| | | | l4 | L |Cable ? | | |Unit Tr.| | | | | c1 | C8 |No.nam 1|No.nam 1|No.nam 1|No.nam 1|No.nam 1|No.nam 1|No.nam 1| | c2 | C8 |No.nam 2|No.nam 2|No.nam 2|No.nam 2|No.nam 2| | | | c3 | C8 | | | | |No.nam 3| | | | c4 | C8 |Elem.nam|Elem.nam|Elem.nam|Elem.nam|Elem.nam|Elem.nam|Elem.nam| | c5 | C10 | | | |Vectorgr|Vectorgr| | | | c6 | C24 | Type | | | Type | | | | | c7 | C8 |Freq.dep| |Freq.dep|Freq.dep|Freq.dep|Freq.dep|Freq.dep| | r1 | N8 | Un | Un | Un | Un1 | Un1 | Un | Un | | r2 | N8 | B1(1) | | | Un2 | Un2 | | | | r3 | N8 | B1(0) | | | Delta U| Un3 | | | | r4 | N8 | G1(1) | | Ur | Ur1 | Ur1 | | | | r5 | N8 | G1(0) | | | Ur2 | Ur2 | | | | r6 | N8 | | | | Beta | Ur3 | | | | r7 | N8 | Ir max | | | Sr | Sr12 | P(1) | Sk"max | | r8 | N8 | X(1) | X(1) | ukr(1) | ukr(1) |ukr(1)12| | Sk"min | | r9 | N8 | X(0) | X(0) | | ukr(0) |ukr(1)23| | | | r10 | N8 |Per.temp| | |reg.side|ukr(1)13| | | | r11 | N8 | R(1) | R(1) | uRr(1) | uRr(1) |uRr(1)12| | | | r12 | N8 | R(0) | R(0) | | uRr(0) |uRr(1)23| | | | r13 | N8 | Y(0) | Y(0) | | Tap act|uRr(1)13| | | | r14 | N8 | Y(1) | Y(1) | | XE1 | XE1 | | | | r15 | N8 | Number | Ir | | XE2 | XE2 | | | | r16 | N8 | ir min | Ipmax | | RE1 | RE1 | | Ik"max | | r17 | N8 | red.fac| | | RE2 | RE2 | | Ik"min | | r18 | N8 | C(1) | | Ir | I0 |ukr(0)12| P(0) | R1/X1 | | r19 | N8 | C(0) | | | Tap min|ukr(0)23| Q(1) | Z0/Z1 | | r20 | N8 | Length | | | Tap max|ukr(0)13| Q(0) | C | | r21 | N8 | B2(1) | | | P Fe | Sr23 | Umin | | | r22 | N8 | B2(0) | | | Tap mit| Sr13 | Umax | | | r23 | N8 | Q | | | Preg | RE3 | Qmin | | | r24 | N8 | Units | | | | XE3 | Qmax | | | r25 | N8 | G2(1) | | | |reg.side| Imax | | | r26 | N8 | G2(0) | | | | Delta U| | | | r27 | N8 | | | | |Tap min | | | | r28 | N8 | | | | |Tap max | | | | r29 | N8 | Ltg_sec| | | |Tap mit | | | | r30 | N8 | Num_sec| | | |Tap akt | | | | c8 | C31 |Descr.N1|Descr.N1|Descr.N1|Descr.N1|Descr.N1|Descr.N1|Descr.N1| | c9 | C31 |Descr.N2|Descr.N2|Descr.N2|Descr.N2|Descr.N2| | | | c10 | C31 | | | | |Descr.N3| | | | c11 | C31 |Descr.El|Descr.El|Descr.El|Descr.El|Descr.El|Descr.El|Descr.El| ----------------------------------------------------------------------------
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Table (continue): ---------------------------------------------------------------------------| Data field| Elements | |--------------------------------------------------------------------------| |Name |Type |Synchron|Asynchro|PS-Unit | Series |Filter |Parallel| Series | |--------------------------------------------------------------------------| | id | N2 | [52] | [53] | [54] | [6] | [55] | [7] | [56] | | l1 | L |Switch 1|Switch 1|Switch 1|Switch 1|Switch 1|Switch 1|Switch 1| | l2 | L |Unit Gen|Conv dri|Turbo ? |Switch 2| |Switch 2| | | l3 | L | | | | | | | | | l4 | L | | | | | | | | | c1 | C8 |No.nam 1|No.nam 1|No.nam 1|No.nam 1|No.nam 1|No.nam 1|No.nam 1| | c2 | C8 |Turbo |Ml(s) | |No.nam 2| |No.nam 2| | | c3 | C8 | |Me(s) | | | | | | | c4 | C8 |Elem.nam|Elem.nam|Elem.nam|Elem.nam|Elem.nam|Elem.nam|Elem.nam| | c5 | C10 | |I(s) |Vectorgr| | | | | | c6 | C24 | Type | Type | | | | | | | c7 | C8 |Freq.dep|Freq.dep|Freq.dep|Freq.dep|Freq.dep|Freq.dep|Freq.dep| | r1 | N8 | Un | Un | Un1 | Un | Un | Un | Un | | r2 | N8 | |Start.de| Un2 | | | | | | r3 | N8 | |P oper. | xd" | | | | | | r4 | N8 | Ur | Ur | Ur1 | Ur | Ur | Ur | Ur | | r5 | N8 |Ufmx/Ufr| Mk/Mr | Ur2 | | | | | | r6 | N8 | | M0 | x(2) | | | | | | r7 | N8 | Sr | Pr | SrT | | Qr | Sr | | | r8 | N8 | mue | Number | ukr(1) | L1 | L1 | L1 | L1 | | r9 | N8 | RE | Ir | ukr(0) | | | | | | r10 | N8 | XE | M1 | xdsat. | | | p | | | r11 | N8 | | M2 | uRr(1) | R1 | R1 | R1 | R1 | | r12 | N8 | |Q oper. | uRr(0) | | | | | | r13 | N8 | | |Cos(phi)| | | | | | r14 | N8 | X(0) | J | XE1 | | | | | | r15 | N8 | RG | sr | RE1 | | f0 | f0 | | | r16 | N8 | Ikk | ETA | | | G | G | | | r17 | N8 |cos(phi)|Polepair| | | | | | | r18 | N8 | xd" |Cos(Phi)| SrG | C1 | C1 | C1 | C1 | | r19 | N8 | x(2) | Ia/Ir |Ufmx/Ufr| | | | | | r20 | N8 | xdges. | Ma/Mr | | | | | | | r21 | N8 | Pmin |t switch| | | | | | | r22 | N8 | Pmax |cos sta.| | | | | | | r23 | N8 | Qmin | RM | | | | | | | r24 | N8 | Qmax | | | | | | | | r25 | N8 | | | | | | | | | r26 | N8 | | | | | | | | | r27 | N8 | | | | | | | | | r28 | N8 | | | | | | | | | r29 | N8 | | | | | | | | | r30 | N8 | | | | | | | | | c8 | C31 |Descr.N1|Descr.N1|Descr.N1|Descr.N1|Descr.N1|Descr.N1|Descr.N1| | c9 | C31 | | | |Descr.N2| |Descr.N2| | | c10 | C31 | | | | | | | | | c11 | C31 |Descr.El|Descr.El|Descr.El|Descr.El|Descr.El|Descr.El|Descr.El| ----------------------------------------------------------------------------
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Table (continue): ------------------------------| Data field| Elements | |-----------------------------| |Name |Type |Serie Eq|Shunt Eq| |-----------------------------| | id | N2 | [11] | [12] | | l1 | L |Switch 1|Switch 1| | l2 | L | | | | l3 | L |Eq.Type |Eq.Type | Eq.Type: 1: Loadflow | l4 | L | | | | c1 | C8 |No.nam 1|No.nam 1| | c2 | C8 |No.nam 2| | | c3 | C8 | | | | c4 | C8 |Elem.nam|Elem.nam| | c5 | C10 | | | | c6 | C24 | | | | c7 | C8 | | | | r1 | N8 | Un1 | Un | | r2 | N8 | Un2 | | | r3 | N8 | | | | r4 | N8 | | | | r5 | N8 | | | | r6 | N8 | | | | r7 | N8 | R12(1) | R(1) | | r8 | N8 | X12(1) | X(1) | | r9 | N8 | R21(1) | R(2) | | r10 | N8 | X21(1) | X(2) | | r11 | N8 | R12(2) | R(0) | | r12 | N8 | X12(2) | X(0) | | r13 | N8 | R21(2) | P gen | | r14 | N8 | X21(2) | Q gen | | r15 | N8 | R12(0) | P loa | | r16 | N8 | X12(0) | Q loa | | r17 | N8 | R21(0) | | | r18 | N8 | X21(0) | | | r19 | N8 | | | | r20 | N8 | | | | r21 | N8 | | | | r22 | N8 | | | | r23 | N8 | | | | r24 | N8 | | | | r25 | N8 | | | | r26 | N8 | | | | r27 | N8 | | | | r28 | N8 | | | | r29 | N8 | | | | r30 | N8 | | | | c8 | C31 |Descr.N1|Descr.N1| | c9 | C31 |Descr.N2| | | c10 | C31 | | | | c11 | C31 |Descr.El|Descr.El| -------------------------------
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As seen above a record consists of 42 data fields. Each data field is described by its name and its type. The following types exist: N2:
Numerical field (integer value)
L:
Logical field (T=True, F=False)
C8:
Character field
C10:
Character field
C24:
Character field
C31:
Character field
N8:
Numerical field (float value)
The first data field "id" gives the type of element. For example with [1] a line will be described. The file is an ASCII-file. The description of the data fields are given in chapter "Element Data Input and Models". The logical switches are saved in L1, L2 and if necessary in L3: L:
"T" merans:
Switch closed (element connected at node 1, 2 or 3)
L:
"F" means:
Switch open
The load and disconnect switches are also exported/imported. Their identifications are: • id = 8: disconnect switch (node-node) • id = 9: load switch (node-node) • id = 10: circuit breaker (node-node) For these elements the logical switches "L3" and "L4" indicate, if the node 1 (starting node) or/and node 2 (ending node) should be reduced during the calculation. "T" means reduce, "F" means not reduce (see "Disconnect Switch" in chapter "Element Data Input and Models"). The data fields are the same as for couplings. The units information for exporting/importing the lines are: • units = 1: Line parameters in OHM/km, µF/km, µS/km and the length in km • units = 2: Line parameters in OHM/miles, µF/miles, µS/miles and the length in miles • units = 3: Line parameters in OHM/1000feet, µF/1000feet, µS/1000feet and the length in 1000feet
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The data of network equivalents are only exported, if the module network reduction is available. Line Sections: Line sections are also included in the EDT-file. The data field "Ltg_sec" gives the information if the record is for a line or a line section: • 0: normal line • 1: line section. For a line consisting of several sections the data field "Num_sec" must contain the number of sections. For example, if a line consists of 3 sections the data field "Num_sec" must contain the number 3. The following data fields are not important for line sections: "l1" to "l3" and "c1" to "c5" and "c7" as well as "r1", "r21" and "r22". The program will calculate the total length and the parameters of the lines, which consist of several sections, when reading the EDT-file (import).
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NDT-File In the NDT-file the node data (load data) are imported or exported. The File can be generated and read by MS-Excel. When exporting the file, the user will be asked about the field seperator to use in the EDT-file. The structure and the description of the record fields are: -----------------------| Data field| | -----------------------|Name |Type | Node | -----------------------| c1 | C8 |Node name | | c2 | C2 | LF-Type | | p | L | HV/LV | | r1 | N8 | Poper inp| | r2 | N8 | Qoper inp| | r3 | N8 | Umin | | r4 | N8 | Umax | | r5 | N8 | U | | r6 | N8 | WU | | c3 | N8 | El.Name | | r8 | N8 | Si.factor| | r9 | N8 | Poper cal| | r10 | N8 | Qoper cal| | c4 | C24 | Type | | p2 | L | Lineload | | r11 | N8 | Distance | | r12 | N8 | DU | | r13 | N8 | xp | | r14 | N8 | xq | | r15 | N8 | P0 | | r16 | N8 | Q0 | | r17 | N8 | Ureg | | r18 | L | Switch | | c5 | C31 | Descr.El.| | r19 | L | No.Info | ------------------------
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Regulated or nominal node voltage Indicates, if the Load is connected (T) or not (F) Indicates, if only the nominal node voltage (T) is read in
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The same is valid as in the ELD file. The fields c1 and c3 can be 8 or 17 characters long. The field p indicates, if the numerical values are given for low (kVA, A, V) or high (MVA, kA, kV) voltage: • p1: "T" means: Input for high voltage. • p1: "F" means: Input for low voltage. The field c2 "LF-Type" gives the node type: Type: "SL" means slack node Type: "PQ" means PQ node Type: "PV" means PQ node more types: "PI", "IC", "PC", "SC". The load type is saved in the field "Type". "Line load" indicates, whether it is a line load or not: • p2: "T" means: line load. • p2: "F" means: load/generator/feeder/motor. The distance of the line load in meter from the line starting node is saved into "Distance". The number of domestic units for the loads and line loads are saved in "DU".
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Measurement Data / Load Factor Files Only text files, whose fields are separated by tabulators, can be read. The fields may have different lengths. A file can contain any number of records. A record can be a behaviour of measurement data or a behaviour of a load factor. A record consists of a header row and of a certain number of data rows. The number of data rows is fixed for week and month factors (7 and 12). It mustn't be greater than a maximum value for the other records. The header row must have the following tabulator-separated entries: Name
Name of profile or name of element to which the measurement data should be assigned
Type
DF = Day factor, WF = Week factor, MF = Month factor, YF = Year factor, LO = Measurement data of a load, MD = behaviour of a measurement device
Unit
A, kA, kW, MW, %
Number of data rows description Day by Hours Characteristic (Day factor) Maximum number of data rows: 96, unit of values: % A data row consists of 3 tabulator-separated fields. Hour
0, 1, 2, ... , 23
Minute
0, 1, 2, ... , 59
Value
>= 0
Week by Days Characteristic (Week factor) Number of data rows: 7, unit of values: % A data row consists of 1 field. Value
>= 0
Year by Months Characteristic (Month factor) Number of data rows: 12, unit of values: % A data row consists of 1 field. Value
>= 0
Long Term by Years Characteristic (Year factor) Maximum number of data rows: 10, unit of values: %
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The first data row consists of only 1 field (year). It is not counted. The following data rows (maximum 10) consist of 2 tabulator-separated fields. Year
Year (4 digits: e.g. 2003)
Value
>= 0
Measurement Data (day profile) Maximum number of data rows: 96, unit of values: %, A, kA, kW or MW A data row consists of 3 tabulator-separated fields: Hour
0, 1, 2, ... , 23
Minute
0, 1, 2, ... , 59
Value Example File with 2 records (1 year factor, 1 day factor): YF_LOW_INCREASE 1984 1989 1 1995 -0.5 1996 0 2000 0.2 2010 0.24 DF_INDUSTRY DF 0 0 50 1 0 48 3 0 49 6 0 54 8 0 92 9 0 96 11 0 100 12 0 98 15 0 92 16 0 92 18 0 83 19 0 80 21 0 70
YF
%
5
Yearfactor: Low increase
%
13
Dayfact.: Industry
Harmonic limit file Limits for harmonic can be entered and stored by Excel. The file name has an extension *.gre. The file consists of 5 rows, which are separated by semicolon: Title of the curve
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1. sub title 2. sub title h
Harmonic
value
Current or voltage value in %.
Example File with 2 curve: VDEW; odd harmonics; not divisible by 3; h; val; ; ; ;5; 6; ; ; ;7; 5; ; ; ;11; 3.5; ; ; ;13; 3; ; ; ;17; 2; ; ; ;19; 1.5; ; ; ;25; 1.5; VDEW; odd harmonics; divisible by 3; h; val; ; ; ;3; 5; ; ; ;9; 1.5; ; ; ;15; 0.3; ; ; ;21; 0.2; ; ; ;51; 0.2;
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