PCS-931 X Instruction Manual En

PCS-931 Line Differential Relay Instruction Manual

NR Electric Co., Ltd.

Preface

Preface Introduction This guide and the relevant operating or service manual documentation for the equipment provide full information on safe handling, commissioning and testing of this equipment. Documentation for equipment ordered from NR is dispatched separately from manufactured goods and may not be received at the same time. Therefore, this guide is provided to ensure that printed information normally present on equipment is fully understood by the recipient. Before carrying out any work on the equipment, the user should be familiar with the contents of this manual, and read relevant chapter carefully. This chapter describes the safety precautions recommended when using the equipment. Before installing and using the equipment, this chapter must be thoroughly read and understood.

Health and Safety The information in this chapter of the equipment documentation is intended to ensure that equipment is properly installed and handled in order to maintain it in a safe condition. When electrical equipment is in operation, dangerous voltages will be present in certain parts of the equipment. Failure to observe warning notices, incorrect use, or improper use may endanger personnel and equipment and cause personal injury or physical damage. Before working in the terminal strip area, the equipment must be isolated. Proper and safe operation of the equipment depends on appropriate shipping and handling, proper storage, installation and commissioning, and on careful operation, maintenance and servicing. For this reason, only qualified personnel may work on or operate the equipment. Qualified personnel are individuals who: 

Are familiar with the installation, commissioning, and operation of the equipment and of the system to which it is being connected;



Are able to safely perform switching operations in accordance with accepted safety engineering practices and are authorized to energize and de-energize equipment and to isolate, ground, and label it;



Are trained in the care and use of safety apparatus in accordance with safety engineering practices;



Are trained in emergency procedures (first aid).

Instructions and Warnings The following indicators and standard definitions are used: PCS-931 Line Differential Relay

i Date: 2014-02-24

Preface

DANGER! It means that death, severe personal injury, or considerable equipment damage will occur if safety precautions are disregarded. WARNING! It means that death, severe personal, or considerable equipment damage could occur if safety precautions are disregarded. CAUTION! It means that light personal injury or equipment damage may occur if safety precautions are disregarded. This particularly applies to damage to the device and to resulting damage of the protected equipment. WARNING! The firmware may be upgraded to add new features or enhance/modify existing features, please make sure that the version of this manual is compatible with the product in your hand. WARNING! During operation of electrical equipment, certain parts of these devices are under high voltage. Severe personal injury or significant equipment damage could result from improper behavior. Only qualified personnel should work on this equipment or in the vicinity of this equipment. These personnel must be familiar with all warnings and service procedures described in this manual, as well as safety regulations. In particular, the general facility and safety regulations for work with high-voltage equipment must be observed. Noncompliance may result in death, injury, or significant equipment damage. DANGER! Never allow the current transformer (CT) secondary circuit connected to this equipment to be opened while the primary system is live. Opening the CT circuit will produce a dangerously high voltage. WARNING! 

Exposed terminals

Do not touch the exposed terminals of this equipment while the power is on, as the high voltage generated is dangerous

ii

PCS-931 Line Differential Relay Date: 2014-02-24

Preface



Residual voltage

Hazardous voltage can be present in the DC circuit just after switching off the DC power supply. It takes a few seconds for the voltage to discharge. CAUTION! 

Earth

The earthing terminal of the equipment must be securely earthed 

Operating environment

The equipment must only be used within the range of ambient environment detailed in the specification and in an environment free of abnormal vibration. 

Ratings

Before applying AC voltage and current or the DC power supply to the equipment, check that they conform to the equipment ratings. 

Printed circuit board

Do not attach and remove printed circuit boards when DC power to the equipment is on, as this may cause the equipment to malfunction. 

External circuit

When connecting the output contacts of the equipment to an external circuit, carefully check the supply voltage used in order to prevent the connected circuit from overheating. 

Connection cable

Carefully handle the connection cable without applying excessive force.

Copyright © 2014 NR. All rights reserved. We reserve all rights to this document and to the information contained herein. Improper use in particular reproduction and dissemination to third parties is strictly forbidden except where expressly authorized. The information in this manual is carefully checked periodically, and necessary corrections will be included in future editio ns. If nevertheless any errors are detected, suggestions for correction or improvement are greatly appreciated. We reserve the rights to make technical improvements without notice.

NR ELECTRIC CO., LTD.

Tel: +86-25-87178888,

Fax: +86-25-87178999

69 Suyuan Avenue. Jiangning, Nanjing 211102, China

Website: www.nrelect.com, www.nari-relays.com

Version: R1.07

PCS-931 Line Differential Relay

iii Date: 2014-02-24

Preface

Documentation Structure The manual provides a functional and technical description of this relay and a comprehensive set of instructions for the relay’s use and application. All contents provided by this manual are summarized as below:

1 Introduction Briefly introduce the application, functions and features about this relay.

2 Technical Data Introduce the technical data about this relay, such as electrical specifications, mechanical specifications, ambient temperature and humidity range, communication port parameters, type tests, setting ranges and accuracy limits and the certifications that our products have passed.

3 Operation Theory Introduce a comprehensive and detailed functional description of all protective elements.

4 Supervision Introduce the automatic self-supervision function of this relay.

5 Management Introduce the management function (measurement, recording and remote control) of this relay.

6 Hardware Introduce the main function carried out by each plug-in module of this relay and providing the definition of pins of each plug-in module.

7 Settings List settings including system settings, communication settings, label settings, logic links and etc., and some notes about the setting application.

8 Human Machine Interface Introduce the hardware of the human machine interface (HMI) module and a detailed guide for the user how to use this relay through HMI. It also lists all the information which can be view through HMI, such as settings, measurements, all kinds of reports etc.

9 Configurable Function Introduce configurable function of the device and all configurable signals are listed.

10 Communication Introduce the communication port and protocol which this relay can support, IEC60970-5-103, IEC61850 and DNP3.0 protocols are introduced in details.

11 Installation iv

PCS-931 Line Differential Relay Date: 2014-02-24

Preface

Introduce the recommendations on unpacking, handling, inspection and storage of this relay. A guide to the mechanical and electrical installation of this relay is also provided, incorporating earthing recommendations. A typical wiring connection to this relay is indicated.

12 Commissioning Introduce how to commission this relay, comprising checks on the calibration and functionality of this relay.

13 Maintenance A general maintenance policy for this relay is outlined.

14 Decommissioning and Disposal A general decommissioning and disposal policy for this relay is outlined.

15 Manual Version History List the instruction manual version and the modification history records.

Typographic and Graphical Conventions Deviations may be permitted in drawings and tables when the type of designator can be obviously derived from the illustration. The following symbols are used in drawings:

&

AND gate ≥1

OR gate

Comparator BI

SET

EN

Binary signal via opto-coupler I>

Input signal from comparator with setting

Input signal of logic setting for function enabling

PCS-931 Line Differential Relay

v Date: 2014-02-24

Preface SIG

Input of binary signal except those signals via opto-coupler

XXX

Output signal

Timer t t

Timer (optional definite-time or inverse-time characteristic) 10ms

0ms

Timer [delay pickup (10ms), delay dropoff (0ms), non-settable] [XXX]

0ms

Timer (delay pickup, settable) 0ms

[XXX]

Timer (delay dropoff, settable) [XXX]

[XXX]

Timer (delay pickup, delay dropoff, settable) IDMT

Timer (inverse-time characteristic)

---xxx is the symbol

Symbol Corresponding Relationship Basic

Example

A, B, C

L1, L2, L3

Ia, Ib, Ic, I0

IL1, IL2, IL3, IN

AN, BN, CN

L1N, L2N, L3N

Ua, Ub, Uc

VL1, VL2, VL3

ABC

L123

Uab, Ubc, Uca

VL12, VL23, VL31

U (voltage)

V

U0, U1, U2

VN, V1, V2

vi

PCS-931 Line Differential Relay Date: 2014-02-24

1 Introduction

1 Introduction Table of Contents 1 Introduction ....................................................................................... 1-a 1.1 Application....................................................................................................... 1-1 1.2 Function ........................................................................................................... 1-3 1.3 Features ........................................................................................................... 1-6

List of Figures Figure 1.1-1 Typical application of PCS-931 ............................................................................. 1-1 Figure 1.1-2 Functional diagram of PCS-931............................................................................ 1-2

PCS-931 Line Differential Relay

1-a Date: 2013-12-27

1 Introduction

PCS-931 Line Differential Relay

1-b Date: 2013-12-27

1 Introduction

1.1 Application PCS-931 is a digital line differential protection with the main and back-up protection functions, which is designed for overhead line or cables and hybrid transmission lines of various voltage levels.

52

52

PCS-931

Optical fibre channel

PCS-931

Communication channel via direct dedicated fibre or MUX

Figure 1.1-1 Typical application of PCS-931

Main protection of PCS-931 comprises current differential protection which can clear any internal fault instantaneously for the whole line. DPFC distance protection can perform extremely high speed operation for close-up faults. There is direct transfer trip (DTT) feature incorporated in the relay. PCS-931 also includes distance protection (3 forward zones and 1 reverse zone distance protection with selectable mho or quadrilateral characteristic), 4 stages directional earth fault protection, 4 stages directional phase overcurrent protection, 2 stages voltage protection (under/over voltage protection), 4 stages frequency protection (under/over frequency protection), broken conductor protection, reverse power protection, pole discrepancy protection, breaker failure protection, thermal overload protection, and dead zone protection etc. Morever, a backup overcurrent and earth fault protection will be automatically enabled when VT circuit fails. In addition, stub overcurrent protection is provided for one and a half breakers arrangement when transmission line is put into maintenance. PCS-931 has selectable mode of single-phase tripping or three-phase tripping and configurable auto-reclosing mode for 1-pole, 3-poles and 1/3-pole operation. PCS-931 with appropriate selection of integrated protection functions can be applied for various voltage levels and primary equipment such as cables, overhead lines, interconnectors and transformer feeder, etc. It also supports configurable binary inputs, binary outputs, LEDs and IEC 61850 protocol.

PCS-931 Line Differential Relay

1-1 Date: 2013-12-27

1 Introduction BUS

52

81 87

21D

21

67G

67P

50G

50P

51G

51P

50GVT

50PVT

50BF

49

46BC

32R

62PD

FR 59 FL

Data Transmitt/Receive

50DZ

27

50STB (Only for one and a half breakers arrangement) SOTF

25

79

LINE

Figure 1.1-2 Functional diagram of PCS-931 No.

Function

ANSI

1

Current differential protection

87

2

DPFC distance protection

21D

3

Distance protection

21

4

Earth fault protection

67G

5

Definite-time earth-fault protection

50G

6

Inverse-time earth-fault protection

51G

8

Phase overcurrent protection

67P

9

Definite-time phase overcurrent protection

50P

10

Inverse-time phase overcurrent protection

51P

11

Overvoltage protection

59

12

Undervoltage protection

27

13

Frequency protection

81

14

Broken conductor protection

46BC

15

Reverse power protection

32R

16

Breaker failure protection

50BF

17

Thermal overload protection

49

18

Stub overcurrent protection

50STB

19

Dead zone protection

50DZ

20

Pole discrepancy protection

62PD

21

Switch onto fault

SOTF

22

Phase overcurrent protection when VT circuit failure

50PVT

23

Earth fault protection when VT circuit failure

50GVT

24

Synchronism check

25

25

Automatic reclosure

79

PCS-931 Line Differential Relay

1-2 Date: 2013-12-27

1 Introduction 26

Fault recorder

FR

27

Fault location

FL

1.2 Function 1.

Protection Function



Current differential protection (87)





Deviation of Power Frequency Component (DPFC) current differential element



Steady-state current differential element



Neutral current differential element

Distance protection 

Three zones forward phase-to-ground distance elements (mho or quadrilateral characteristic)



One zone reverse phase-to-ground distance element (mho or quadrilateral characteristic)



Three zones forward phase-to-phase distance elements (mho or quadrilateral characteristic)



One zone reverse phase-to-phase distance element (mho or quadrilateral characteristic)



Load encroachment for mho and quadrilateral characteristic distance element



Power swing blocking releasing, selectable for each of above mentioned zones



Deviation of Power Frequency Component (DPFC) distance protection



Current protection





Four stages phase overcurrent protection, selectable time characteristic (definite-time or inverse-time) and directionality (forward direction, reverse direction or non-directional)



Four stages directional earth fault protection, selectable time characteristic (definite-time or inverse-time) and directionality (forward direction, reverse direction or non-directional)

Breaker failure protection 

Optional instantaneously re-tripping



One stage with two delay timers



Thermal overload protection



Stub overcurrent protection



Dead zone protection



Pole discrepancy protection



Broken conductor protection

PCS-931 Line Differential Relay

1-3 Date: 2013-12-27

1 Introduction 

Reverse power protection



Switch onto fault (SOTF)













Via distance measurement elements



Via dedicated earth fault element

Backup protection when VT circuit failure 

Phase overcurrent protection when VT circuit failure



Earth fault protection when VT circuit failure

Voltage protection 

Two stages overvoltage protection



Two stages undervoltage protection

Frequency protection 

Four stages overfrequency protection



Four stages underfrequency protection



f/dt block criterion for underfrequency protection

Control function 

Synchro-checking



Automatic reclosure (single shot or multi-shot (max. 4) for 1-pole AR and 3-pole AR)

Communication scheme of current differential protection 

Direct optical link



Connection to a communication network, support G.703 and C37.94 protocol



Dual-channels redundancy

2.

Measurement and control function



Remote control (open and closing)



Synchronism check for remote and manual closing (only for one circuit breaker)



Energy metering (active and reactive energy are calculated in import respectively export direction)

3.

Logic



User programmable logic

4.

Additional function



Fault location

PCS-931 Line Differential Relay

1-4 Date: 2013-12-27

1 Introduction 

Fault phase selection



Parallel line compensation for fault location



VT circuit supervision



CT circuit supervision



Self diagnostic



DC power supply supervision



Event Recorder including 1024 disturbance records, 1024 binary events, 1024 supervision events, 256 control logs and 1024 device logs.



Disturbance recorder including 32 disturbance records with waveforms (The file format of disturbance recorder is compatible with international COMTRADE file.)



Four kinds of clock synchronization methods 







Conventional 

PPS (RS-485): Pulse per second (PPS) via RS-485 differential level



IRIG-B (RS-485): IRIG-B via RS-485 differential level



PPM (DIN): Pulse per minute (PPM) via the optical coupler



PPS (DIN): Pulse per second (PPS) via the optical coupler

SAS 

SNTP (PTP): Unicast (point-to-point) SNTP mode via Ethernet network



SNTP (BC): Broadcast SNTP mode via Ethernet network



Message (IEC103): Clock messages through IEC103 protocol

Advanced 

IEEE1588: Clock message via IEEE1588



IRIG-B (Fiber): IRIG-B via optical-fibre interface



PPS (Fiber) PPS: Pulse per second (PPS) via optical-fibre interface

NoTimeSync

5.

Monitoring



Number of circuit breaker operation (single-phase tripping, three-phase tripping and reclosing)



Channel status



Frequency

6.

Communication

PCS-931 Line Differential Relay

1-5 Date: 2013-12-27

1 Introduction 

Optional 2 RS-485 communication rear ports conform to IEC 60870-5-103 protocol



1 RS-485 communication rear ports for clock synchronization



Optional 2 or 4 Ethernet ports (depend on the chosen type of MON plug-in module) conform to IEC 61850 protocol, DNP3.0 protocol or IEC 60870-5-103 protocol over TCP/IP



Optional 2 Ethernet ports via optic fiber (ST interface) conform to IEC 61850 protocol, DNP3.0 protocol or IEC 60870-5-103 protocol over TCP/IP



GOOSE and SV communication function (optional NET-DSP plug-in module)

7.

User Interface



Friendly HMI interface with LCD and 9-button keypad on the front panel.



1 front multiplex RJ45 port for testing and setting



1 RS-232 or RS-485 rear ports for printer



Language switchover—English+ selected language



Auxiliary software—PCS-Explorer

1.3 Features 

The intelligent device integrated with protection, control and monitor provides powerful protection function, flexible protection configuration, user programmable logic and configurable binary input and binary output, which can meet with various application requirements.



High-performance hardware platform and modularized design, MCU (management control unit)＋DSP (digital signal processor). MCU manages general fault detector element and DSP manages protection and metering. Their data acquisition system is completely independent in electronic circuit. DC power supply of output relay is controlled by the operation of fault detector element operates, this prevents maloperation due to error from ADC or damage of any apparatus.



Fast fault clearance for faults within the protected line, the operating time is less than 10 ms for close-up faults, less than 15ms for faults in the middle of protected line and less than 25ms for remote end faults.



The unique DPFC distance element integrated in the protective device provides extremely high speed operation and insensitive to power swing.



Self-adaptive floating threshold which only reflects deviation of power frequency component improves the protection sensitivity and stability under the condition of load fluctuation and system disturbance.



Advanced and reliable power swing blocking releasing feature which ensure distance protection operate correctly for internal fault during power swing and prevent distance protection from maloperation during power swing PCS-931 Line Differential Relay

1-6 Date: 2013-12-27

1 Introduction 

Flexible automatic reclosure supports various initiation modes and check modes



Multiple setting groups with password protection and setting value saved permanently before modification



Powerful PC tool software can fulfill protection function configuration, modify setting and waveform analysis.

PCS-931 Line Differential Relay

1-7 Date: 2013-12-27

1 Introduction

PCS-931 Line Differential Relay

1-8 Date: 2013-12-27

2 Technical Data

2 Technical Data Table of Contents 2 Technical Data ................................................................................... 2-a 2.1 Electrical Specifications ................................................................................. 2-1 2.1.1 AC Current Input .................................................................................................................. 2-1 2.1.2 AC Voltage Input .................................................................................................................. 2-1 2.1.3 Power Supply ....................................................................................................................... 2-1 2.1.4 Binary Input .......................................................................................................................... 2-1 2.1.5 Binary Output ....................................................................................................................... 2-2

2.2 Mechanical Specifications.............................................................................. 2-2 2.3 Ambient Temperature and Humidity Range .................................................. 2-3 2.4 Communication Port ....................................................................................... 2-3 2.4.1 EIA-485 Port ........................................................................................................................ 2-3 2.4.2 Ethernet Port ........................................................................................................................ 2-3 2.4.3 Optical Fibre Port ................................................................................................................. 2-3 2.4.4 Print Port .............................................................................................................................. 2-4 2.4.5 Clock Synchronization Port ................................................................................................. 2-4

2.5 Type Tests ........................................................................................................ 2-5 2.5.1 Environmental Tests............................................................................................................. 2-5 2.5.2 Mechanical Tests ................................................................................................................. 2-5 2.5.3 Electrical Tests ..................................................................................................................... 2-5 2.5.4 Electromagnetic Compatibility ............................................................................................. 2-5

2.6 Certifications ................................................................................................... 2-6 2.7 Terminals ......................................................................................................... 2-6 2.8 Measurement Scope and Accuracy ............................................................... 2-6 2.9 Management Function .................................................................................... 2-7 2.9.1 Control Performance............................................................................................................ 2-7

PCS-931 Line Differential Relay

2-a Date: 2014-02-24

2 Technical Data

2.9.2 Clock Performance .............................................................................................................. 2-7 2.9.3 Fault and Disturbance Recording ........................................................................................ 2-7 2.9.4 Binary Input Signal............................................................................................................... 2-7

2.10 Protective Functions..................................................................................... 2-7 2.10.1 Fault Detector .................................................................................................................... 2-7 2.10.2 Current Differential Protection ........................................................................................... 2-8 2.10.3 Distance Protection ............................................................................................................ 2-8 2.10.4 Phase Overcurrent Protection ........................................................................................... 2-8 2.10.5 Earth Fault Protection ........................................................................................................ 2-8 2.10.6 Overvoltage Protection ...................................................................................................... 2-8 2.10.7 Undervoltage Protection .................................................................................................... 2-9 2.10.8 Overfrequency Protection .................................................................................................. 2-9 2.10.9 Underfrequency Protection ................................................................................................ 2-9 2.10.10 Breaker Failure Protection ............................................................................................... 2-9 2.10.11 Thermal Overload Protection ........................................................................................... 2-9 2.10.12 Stub Overcurrent Protection .......................................................................................... 2-10 2.10.13 Dead Zone Protection .................................................................................................... 2-10 2.10.14 Pole Discrepancy Protection ......................................................................................... 2-10 2.10.15 Broken Conductor Protection ........................................................................................ 2-10 2.10.16 Reverse Power Protection ............................................................................................. 2-10 2.10.17 Auto-reclosing .................................................................................................................2-11 2.10.18 Transient Overreach .......................................................................................................2-11 2.10.19 Fault Locator ...................................................................................................................2-11

PCS-931 Line Differential Relay

2-b Date: 2014-02-24

2 Technical Data

2.1 Electrical Specifications 2.1.1 AC Current Input Phase rotation

ABC

Nominal frequency (fn)

50Hz, 60Hz

Rated current (In)

1A

Linear to

5A

0.05In~40In (It should measure current without beyond full scale against 20 times of related current and value of DC offset by 100%.)

Thermal withstand -continuously

4In

-for 10s

30In

-for 1s

100In

-for half a cycle

250In

Burden

< 0.15VA/phase @In

Number

Up to 7 current input according to various applications

< 0.25VA/phase @In

2.1.2 AC Voltage Input Phase rotation

ABC

Nominal frequency (fn)

50Hz, 60Hz

Rated voltage (Un)

100V~130V

Linear to

1V~170V

Thermal withstand -continuously

200V

-10s

260V

-1s

300V

Burden at rated

< 0.20VA/phase @Un

Number

Up to 6 voltage input according to various applications

2.1.3 Power Supply Standard

IEC 60255-11:2008

Rated voltage

110Vdc/125Vdc/220Vdc/250Vdc

Permissible voltage range

88~300Vdc

Permissible AC ripple voltage

≤15% of the nominal auxiliary voltage

Burden Quiescent condition

[AuxE.ROC3.3I0_Set] Where: 3I0: The calculated residual current 3.

Phase current auxiliary element AuxE.OC

3-10

PCS-931 Line Differential Relay Date: 2014-03-05

3 Operation Theory

There are 3 stages for phase current auxiliary element (AuxE.OC1, AuxE.OC2 and AuxE.OC3). Each phase current auxiliary element will operate instantly if phase current amplitude is larger than corresponding current setting. The criteria are: AuxE.OC1: IΦMAX>[AuxE.OC1.I_Set] AuxE.OC2: IΦMAX>[AuxE.OC2.I_Set] AuxE.OC3: IΦMAX>[AuxE.OC3.I_Set] Where: IΦMAX: The maximum phase current among three phases 4.

Voltage change auxiliary element AuxE.UVD

AuxE.UVD is based on phase-to-ground voltage change measured in all three phases. The criterion is: ΔUΦMAX>[AuxE.UVD.U_Set] Where: ΔUΦMAX: The maximum phase-to-ground voltage change among three phases 5.

Phase under voltage auxiliary element AuxE.UVG

AuxE.UVG will operate instantly if any phase-to-ground voltage is lower than corresponding voltage setting. The criterion is: UΦMIN[AuxE.ROC1.3I0_Set]

AuxE.ROC1.En

& AuxE.ROC1.St

& SIG

AuxE.ROC1.Blk

En

AuxE.ROC1.En

SIG

AuxE.ROC2.En

AuxE.ROC1.On 3I0>[AuxE.ROC2.3I0_Set]

& AuxE.ROC2.St

& SIG

AuxE.ROC2.Blk

En

AuxE.ROC2.En

SIG

AuxE.ROC3.En

AuxE.ROC2.On 3I0>[AuxE.ROC3.3I0_Set]

SIG

AuxE.ROC3.Blk

En

AuxE.ROC3.En

& AuxE.ROC3.St

&

AuxE.ROC3.On

3-16

PCS-931 Line Differential Relay Date: 2014-03-05

3 Operation Theory SIG

Ia

Ia>[AuxE.OC1.I_Set]

& AuxE.OC1.StA

SIG

Ib

Ib>[AuxE.OC1.I_Set]

& AuxE.OC1.StB

SIG

Ic

Ic>[AuxE.OC1.I_Set]

& AuxE.OC1.StC

>=1 SIG

&

AuxE.OC1.En

AuxE.OC1.St

& SIG

AuxE.OC1.Blk

En

AuxE.OC1.En

SIG

Ia

AuxE.OC1.On Ia>[AuxE.OC2.I_Set]

& AuxE.OC2.StA

SIG

Ib

Ib>[AuxE.OC2.I_Set]

& AuxE.OC2.StB

SIG

Ic

Ic>[AuxE.OC2.I_Set]

& AuxE.OC2.StC

>=1 SIG

&

AuxE.OC2.En

AuxE.OC2.St

& SIG

AuxE.OC2.Blk

En

AuxE.OC2.En

SIG

Ia

AuxE.OC2.On Ia>[AuxE.OC3.I_Set]

& AuxE.OC3.StA

SIG

Ib

Ib>[AuxE.OC3.I_Set]

& AuxE.OC3.StB

SIG

Ic

Ic>[AuxE.OC3.I_Set]

& AuxE.OC3.StC

>=1 SIG

&

AuxE.OC3.En

AuxE.OC3.St

& SIG

AuxE.OC3.Blk

En

AuxE.OC4.En

AuxE.OC3.On

3-17

PCS-931 Line Differential Relay Date: 2014-03-05

3 Operation Theory SIG

Ua

SIG

Ub

SIG

Uc

ΔUa>[AuxE.UVD.U_Set]

Calculate DPFC phase voltage △Ua=△(Ua-Ufa) △Ub=△(Ub-Ufb) △Uc=△(Uc-Ufc)

>=1 ΔUb>[AuxE.UVD.U_Set]

& AuxE.UVD.St

ΔUc>[AuxE.UVD.U_Set] 0s

SIG

[AuxE.UVD.t_Ext]

AuxE.UVD.En

AuxE.UVD.St_Ext

& SIG

AuxE.UVD.Blk

En

AuxE.UVD.En

SET

AuxE.UVD.On

UA=1 SIG

AuxE.OC2.St

SIG

AuxE.OC3.St

SIG

AuxE.UVD.St_Ext

SIG

AuxE.UVG.St

SIG

AuxE.UVS.St

SIG

AuxE.ROV.St

>=1 >=1

>=1

Figure 3.5-1 Logic diagram of auxiliary element

3.5.6 Settings Table 3.5-2 Settings of auxiliary element No. 1

Name AuxE.OCD.t_DDO

Range 0.000~10.000

Step 0.001

Unit s

Remark Drop-off time delay of current change auxiliary element Enabling/disabling current change

2

AuxE.OCD.En

auxiliary element

0 or 1

0: disable 1: enable

3

AuxE.ROC1.3I0_Set

(0.050~30.000)×In

0.001

A

Current setting of stage 1 residual current auxiliary element Enabling/disabling stage 1 residual

4

AuxE.ROC1.En

current auxiliary element

0 or 1

0: disable 1: enable

5

AuxE.ROC2.3I0_Set

(0.050~30.000)×In

0.001

A

Current setting of stage 2 residual current auxiliary element Enabling/disabling stage 2 residual

6

AuxE.ROC2.En

current auxiliary element

0 or 1

0: disable 1: enable

7

AuxE.ROC3.3I0_Set

(0.050~30.000)×In

0.001

A

Current setting of stage 3 residual current auxiliary element Enabling/disabling stage 3 residual

8

AuxE.ROC3.En

current auxiliary element

0 or 1

0: disable 1: enable

9

AuxE.OC1.I_Set

(0.050~30.000)×In

Current setting of stage 1 phase current 3-19

PCS-931 Line Differential Relay Date: 2014-03-05

3 Operation Theory auxiliary element Enabling/disabling stage 1 phase 10

AuxE.OC1.En

current auxiliary element

0 or 1

0: disable 1: enable

11

AuxE.OC2.I_Set

Current setting of stage 2 phase current

(0.050~30.000)×In

auxiliary element Enabling/disabling stage 2 phase

12

AuxE.OC2.En

current auxiliary element

0 or 1

0: disable 1: enable

13

AuxE.OC3.I_Set

Current setting of stage 3 phase current

(0.050~30.000)×In

auxiliary element Enabling/disabling stage 3 phase

14

AuxE.OC3.En

current auxiliary element

0 or 1

0: disable 1: enable

15

AuxE.UVD.U_Set

0~Un

0.001

V

16

AuxE.UVD.t_DDO

0.000~10.000

0.001

s

Voltage setting for voltage change auxiliary element Drop-off time delay of voltage change auxiliary element Enabling/disabling voltage change

17

AuxE.UVD.En

auxiliary element

0 or 1

0: disable 1: enable

18

AuxE.UVG.U_Set

0~Un

0.001

V

Voltage setting for phase-to-ground under voltage auxiliary element Enabling/disabling phase-to-ground

19

AuxE.UVG.En

under voltage auxiliary element

0 or 1

0: disable 1: enable

20

AuxE.UVS.U_Set

0~Unn

0.001

V

Voltage setting for phase-to-phase under voltage auxiliary element Enabling/disabling phase-to-phase

21

AuxE.UVS.En

under voltage auxiliary element

0 or 1

0: disable 1: enable

22

AuxE.ROV.3U0_Set

0~Un

0.001

V

Voltage setting for residual voltage auxiliary element Enabling/disabling residual voltage

23

AuxE.ROV.En

auxiliary element

0 or 1

0: disable 1: enable

3-20

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3 Operation Theory

3.6 Distance Protection 3.6.1 General Application When a fault happens on a power system, distance protection will trip circuit breaker to isolate the fault from power system with its specific time delay if the fault is within the protected zone of distance protection.

3.6.2 Function Description The device comprises 3 forward zones and 1 reverse zone. For each independent distance element zone, full scheme design provides continuous measurement of impedance separately in three independent phase-to-phase measuring loops as well as in three independent phase-to-ground measuring loops. Selection of zone characteristic between mho and quadrilateral is available. Distance protection includes: 1.

DPFC distance protection It is independent fast protection providing extremely fast speed to clear close up fault especially on long line and thus improves system stability.

2.

Mho phase-to-phase distance protection Zone1~3: forward direction Zone 4: reverse direction including origin

3.

Mho phase-to-ground distance protection Zone1~3: forward direction Zone 4: reverse direction including origin

4.

Quadrilateral phase-to-phase distance protection Zone1~3: forward direction Zone 4: reverse direction

5.

Quadrilateral phase-to-ground distance protection Zone1~3: forward direction Zone 4: reverse direction

6.

Load encroachment It is used to prevent all distance elements from undesired trip due to load encroachment under heavy load condition especially for long lines.

7.

Power swing detection (PSD)

8.

Power swing blocking releasing (PSBR) For power swing with external fault, distance protection is always blocked, but for power 3-21

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3 Operation Theory

swing with internal fault, PSBR will operate to release the blocking for distance protection. 9.

SOTF distance protection For manual closing or automatic closing on to a fault, zone 2 or 3 of distance protection will accelerate to trip.

When VT circuit fails, VT circuit supervision logic will output a blocking signal to block all distance protection except DPFC distance protection. The operating threshold will be increased to 1.5U N to enhance stability. Distance protection can select line VT or bus VT for protection algorithm by a setting [VTS.En_LineVT]. When no VT is provided, logic setting [VTS.En_Out_VT] should be set as “1”, all distance protection will be blocked automatically. The coordination among zones of distance protection is shown in the following figure.

Z4

EM

M

A

B

P

C

D

N

EN

Z1、DZ Z2

Z3

Figure 3.6-1 Protected reach of distance protection for each zone

Where: Z1: forward direction zone 1 Z2: forward direction zone 2 Z3: forward direction zone 3 Z4: reverse direction zone 4 DZ: DPFC distance protection The choice of impedance reach is as follow. (only for reference) The zone 1 impedance reach setting should be set to cover as much the protected line as possible but not to respond faults beyond the protected line. The accuracy of the relay distance elements is ±2.5% in general applications, however, the error could be much larger due to errors of current transformer, voltage transformer and inaccuracies of line parameter from which the relay settings are calculated. It is recommended the zone 1 reach is set to 80%~85% of the protected line in consideration the aforesaid errors and safety margin to prevent instantaneously tripping for faults on adjacent lines. The remaining 20% of the protected line relies on the zone 2 distance elements. The general rule for zone 2 impedance reach setting is set to cover the protected line plus 20% of 3-22

PCS-931 Line Differential Relay Date: 2014-03-05

3 Operation Theory

the adjacent line. However, the coverage of adjacent line should be extended in the presence of additional infeed at the remote end of the protected line to ensure 20% coverage of adjacent line. This assures the fast operation of zone 2 distance element for faults at the remote end of the protected line since the fault is well within zone 2 reach. In a parallel line situation, a fault cleared sequentially on a line may cause current reversal in the healthy line. The Z3 distance element acts as backup protection for protected line and adjacent line but not to over the zone 2 setting of adjacent line. The zone 3 impedance reach is generally 2 times zone 1 reach, i.e. 160% of protected line. For different system impedance ratio (SIR), the operating time of distance protection for different fault location are shown as the following figures.

35 30 25 Operating Time (ms)

20 15 10 5 0 0

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-2 Operating time of single-phase fault (50Hz, SIR=1)

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3 Operation Theory

30 25 Operating Time (ms)

20 15 10 5 0 0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-3 Operating time of single-phase fault (60Hz, SIR=1)

35 30 25 Operating Time (ms)

20 15 10 5 0 0

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-4 Operating time of two-phase fault (50Hz, SIR=1)

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3 Operation Theory

30 25 Operating Time (ms)

20 15 10 5 0 0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-5 Operating time of two-phase fault (60Hz, SIR=1)

35 30 25 Operating Time (ms)

20 15 10 5 0 0

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-6 Operating time of three-phase fault (50Hz, SIR=1)

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3 Operation Theory

30 25 Operating Time (ms)

20 15 10 5 0 0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-7 Operating time of three-phase fault (60Hz, SIR=1)

33 32.5 32 Operating Time (ms)

31.5

31 30.5

30 29.5

29 0%

10%

20%

30%

40%

50%

60%

70%

80%

90% 100%

Fault Location (% of relay setting)

Figure 3.6-8 Operating time of single-phase fault (50Hz, SIR=30)

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3 Operation Theory

27.5 27 Operating Time (ms)

26.5 26 25.5 25 24.5 24 0%

10%

20%

30%

40%

50%

60%

70%

80%

90% 100%

Fault Location (% of relay setting)

Figure 3.6-9 Operating time of single-phase fault (60Hz, SIR=30)

45 40 35 Operating Time (ms)

30 25 20 15 10 5 0 0

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-10 Operating time of two-phase fault (50Hz, SIR=30)

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3 Operation Theory

35 30 Operating Time (ms)

25 20 15 10 5 0 0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-11 Operating time of two-phase fault (60Hz, SIR=30)

33 32 Operating Time (ms)

31 30 29 28 27 0

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Fault Location (% of relay setting)

Figure 3.6-12 Operating time of three-phase fault (50Hz, SIR=30)

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3 Operation Theory

27.5 27 Operating Time (ms)

26.5 26

25.5 25

24.5 24

23.5 0%

10%

20%

30%

40%

50%

60%

70%

80%

90% 100%

Fault Location (% of relay setting)

Figure 3.6-13 Operating time of three-phase fault (60Hz, SIR=30)

3.6.3 DPFC Distance Protection The power system is normally treated as a balanced symmetrical three-phase network. When a fault occurs in the power system, by applying the principle of superposition, the load current and voltage can be calculated in the system prior to the fault and the pure fault component can be calculated by fault current or voltage subtracted by pre-fault load current or voltage. DPFC distance protection concerns change of current and voltage at power frequency, therefore, DPFC distance protection is not influenced by load current. As an independent fast protection, DPFC distance protection is mainly used to clear close up fault of long line quickly, its protected range can set as 80%~85% of the whole line. Since DPFC distance protection only reflects fault component and is not influenced by current change due to load variation and power swing, power swing blocking (PSB) is this not required. Moreover, there is no transient overreaching due to infeed current from the remote power supply because it is not influenced by load current. DPFC distance protection may not overreach, and its protected zone will be inverse-proportion reduced with system impedance behind it, i.e. the protected zone will be less than setting if the system impedance is greater. The protected zone will be close to setting value if the system impedance is smaller. Therefore, DPFC distance protection is usually used for long transmission line with large power source and it is recommended to disable DPFC distance protection for short line or the line with weak power source.

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3 Operation Theory

3.6.3.1 Impedance Characteristic ZZD M

EM

F

Z

N

EN

∆I ZS

ZK

jX

Zzd Zk

Φ

Zs+Zk

R

-Zs

Figure 3.6-14 Operation characteristic for forward fault

Where: ZZD: the setting of DPFC distance protection ZS: total impedance between local system and device location ZK: measurement impedance Φ: positive-sequence sensitive angle, i.e. [phi1_Reach] Figure 3.6-14 shows the operation characteristic of DPFC distance protection on R-X plane when a fault occurs in forward direction, which is the circle with the –Zs as the center and the│Zs+Zzd│ as the radius. When measured impedance Z k is in the circle, DPFC distance protection will operate. DPFC distance protection has a larger capability of enduring fault resistance than distance protection using positive-sequence as polarized voltage.

3-30

PCS-931 Line Differential Relay Date: 2014-03-05

3 Operation Theory ZZD F

M

EM

N

Z

EN

∆I ZK Z′S

jX

Z's

Zzd

Φ

R

-Zk

Figure 3.6-15 Operation characteristic for reverse fault

Z'S：total impedance between remote system and protective device location Figure 3.6-15 shows the operation characteristic of the DPFC distance element on R-X plane when a fault occurs in reverse direction, which is the circle with the Z′S as the center and the│Z′S-Zzd│as the radius. The region of operation is in the quadrant 1 but the measured impedance -Zk is always in the quadrant 3, the DPFC distance protection will not operate. The DPFC distance protection can be enabled or disabled by logic setting and binary input. 3.6.3.2 Function Block Diagram

21D 21D.En

21D.Op

21D.Blk

21D.On

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3 Operation Theory

3.6.3.3 I/O Signals Table 3.6-1 I/O signals of DPFC distance protection No.

Input Signal

1

21D.En

2

21D.Blk

No.

Description DPFC distance protection enabling input, it is triggered from binary input or programmable logic etc. DPFC distance protection blocking input, it is triggered from binary input or programmable logic etc.

Output Signal

Description

1

21D.Op_Set

DPFC distance protection operates.

2

21D.On

DPFC distance protection is enabled.

3.6.3.4 Logic EN

[21D.En]

21D.On

&

SIG

21D.En

SIG

21D.Blk

SIG

FD.Pkp

EN

[VTS.En_Out_VT]

SIG

Manual closing signal

SIG

3-pole reclosing signal

SET

[21D.Z_Set]