Motor Starting

Advanced Motor Starting Analysis Program

EDSA MICRO CORPORATION

16870 West Bernardo Drive, Suite 330 San Diego, CA 92127 U.S.A. © Copyright 2008 All Rights Reserved

Version 4.20.00

October 2008

Advanced Motor Starting Analysis

EDSA MICRO CORPORATION WARRANTY INFORMATION

There is no warranty, implied or otherwise, on EDSA software. EDSA software is licensed to you as is. This program license provides a ninety (90) day limited warranty on the diskette that contains the program. This, the EDSA User’s Guide, is not meant to alter the warranty situation described above. That is, the content of this document is not intended to, and does not, constitute a warranty of any sort, including warranty of merchantability or fitness for any particular purpose on your EDSA software package. EDSA Micro Corporation reserves the right to revise and make changes to this User's Guide and to the EDSA software without obligation to notify any person of, or provide any person with, such revision or change. EDSA programs come with verification and validation of methodology of calculation based on EDSA Micro Corporation's inhouse software development standards. EDSA performs longhand calculation and checks the programs’ results against published samples. However, we do not guarantee, or warranty, any program outputs, results, or conclusions reached from data generated by any programs which are all sold "as is". Since the meaning of QA/QC and the verification and validation of a program methodology are domains of vast interpretation, users are encouraged to perform their own inhouse verification and validation based on their own inhouse quality assurance, quality control policies and standards. Such operations - performed at the user's expense will meet the user's specific needs. EDSA Micro Corporation does not accept, or acknowledge, purchase instructions based on a buyer's QA/QC and/or a buyer's verification and validation standards. Therefore, purchase orders instructions are considered to be uniquely based on EDSA's own QA/QC verification and validation standards and test systems.

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Advanced Motor Starting Analysis

Table of Contents Foreword................................................................................................................................................................1 Introduction ...........................................................................................................................................................1 Individual Dynamic Motor Starting.......................................................................................................................3 3.1 Input Data ......................................................................................................................................................3 3.2 Motor Starting Using Motor Equivalent Circuit ............................................................................................7 3.3 Motor Starting Using Motor Testing Characteristics/SKVA.........................................................................8 3.4 Assessing Adequacy of Motor Electrical Torque and Load Torque Curve Fitting........................................9 3.5 Motor Decrement Export Function from Advanced Motor Starting to Protective Device Coordination ....11 4. Simultaneous Multi-Motor Starting Snapshots....................................................................................................24 APPENDIX A: Dynamic Motor Start Tutorial............................................................................................................27 A Tutorial No. 1: Full Voltage Start........................................................................................................................32 B Tutorial No. 2: Solid State Voltage Control ........................................................................................................40 C Tutorial No. 3: Solid State Current Limit ............................................................................................................44 D Tutorial No. 4: Solid State Current Ramp ...........................................................................................................47 E Tutorial No. 5: Solid State Voltage Ramp ...........................................................................................................50 F Tutorial No. 6: Solid State Torque Ramp ............................................................................................................52 APPENDIX B: Simultaneous Multi-Motor Starting Snapshots method Tutorial........................................................56 G Network under Study...........................................................................................................................................56

1. 2. 3.

List of Figures Figure 1: Motor Starting Options dialog box.................................................................................................................2 Figure 2: Motor Input Data editor dialog box................................................................................................................2 Figure 3: General Motor Dynamic Information.............................................................................................................3 Figure 4: Motor Starter Data Dialog..............................................................................................................................5 Figure 5: Equivalent Circuit Method Data Dialog.........................................................................................................6 Figure 6:For calculating Equivalent Circuit Parameter .................................................................................................7 Figure 7: Equivalent Circuit Motor Model ....................................................................................................................8 Figure 8:Defining Motor Characteristics as a Function of Speed..................................................................................9 Figure 9: Selecting Electrical Torque Assessment and Load Torque Fitting Option ..................................................10 Figure 10: Motor Start Testing and Load Torque Curve Fitting..................................................................................11 Figure 11: Motor “Motor Start” dialog box.................................................................................................................25 Figure 12: Network under study ..................................................................................................................................27 Figure 13: Set Starting Motor ......................................................................................................................................32 Figure 14: General Motor Dynamic Data ....................................................................................................................33 Figure 15: Motor Starter Selection ..............................................................................................................................34 Figure 16: Equivalent Circuit Parameters and Load Torque .......................................................................................35 Figure 17: Motor Starting Tool Bar.............................................................................................................................36 Figure 18: Motor Starting Options ..............................................................................................................................37 Figure 19: Motor Start Report Manager ......................................................................................................................38 Figure 20: Network under Study (File name: MX339.Axd)........................................................................................56 Figure 21: Generator Data ...........................................................................................................................................58 Figure 22: Generator Voltage Angle ...........................................................................................................................58 Figure 23: Motor Data under Motor Start....................................................................................................................59 Figure 24: Motor Data under Short Circuit .................................................................................................................59 Figure 25: Motor Starting Options ..............................................................................................................................60 Figure 26: Report Manager..........................................................................................................................................61

List of Tables Table 1: Results comparison between the different motor starting methods. ............................................................29 Table 2: Comparison to IEEE Standard.....................................................................................................................63 ii

Advanced Motor Starting Analysis

1. Foreword EDSA Advanced Motor Starting Analysis (Load Flow Method) program is designed for motor starting studies in power distribution systems. It is assumed the user is a professional engineer familiar with motor parameters and voltage dip concepts during motor starting. The interpretation and use of the calculation results encompassed by this program are solely the user’s responsibility. All EDSA programs and related documents are the sole property of EDSA MICRO CORPORATION, and are provided to the user’s company subject to the EDSA LICENSE AGREEMENT for the company's use only. None of these programs should be supplied, neither loaned to any third party, nor copied, nor reproduced in any form without the express written permission of EDSA MICRO CORPORATION. All copies and reproductions shall be the property of EDSA MICRO CORPORATION and must bear the copyright notice and ownership statement in their entirety.

2. Introduction One of the most common disturbances in a power system is the sudden application of a load on a distribution system, such as starting a motor, or a group of motors, at the same time. Most of the motors used in the industry, if started on full voltage, will draw a current as high as 5 to 8 times of their full normal running current. This sudden surge of current to the motor from the power distribution system results in an excessive drop of voltage on the bus feeding the motor. The voltage recovers to normal value as the motor current diminishes from the high starting inrush value to its final normal running value. This process may take several cycles, or seconds, depending on the motor size and its starting condition. During the starting period, the voltage dip can cause disturbance to other loads on the nearby buses. Such disturbances could be: dimming lights, loss of X-ray pictures, dropping out of energized coils with as little as a 15% voltage dip, and the loss of sensitive equipment such as computer units. The purpose of the program calculations, therefore, is to give an insight to the voltage condition on various buses so that an educated judgment can be made, and corresponding actions be taken to alleviate the voltage disturbances. The program incorporates the recommended procedure outlined in the IEEE Brown Book for motor starting using the power flow engine. The program provides two simulation methods: Individual Dynamic Motor Start and Simultaneous MultiMotor Starting Snapshots, as shown in the following option dialog box (Figure 1). Figure 2 shows how to set a motor as a “to be started”- just turn on the “To Be Started” button.

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Figure 1: Motor Starting Options dialog box

Figure 2: Motor Input Data editor dialog box

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3. Individual Dynamic Motor Starting 3.1 Input Data This is an accurate and fast method of assessing motor starting conditions without resorting to a time domain simulation program. If more than one motor is set to “to be started” in this simulation method, the program will start one motor, stop it and then start the second motor. The following data are required to perform motor starting simulation: • • • •

Motor impedances and ratings Motor and Load moment of inertia Motor load characteristics Motor assisted starting scenario

The Motor Dynamic Information dialog box as shown in Figure 3 is a main place to enter the data for this method.

Figure 3: General Motor Dynamic Information The program will carry a series of power flows to determine motor performance as a function of time during the motor’s starting period. At each iteration, the motor’s swing equation (equation of rotation) is also solved to obtain 3

Advanced Motor Starting Analysis

the motor’s speed. The result of the motor starting analysis is a time-based tabulation of motor current, motor terminal voltage, motor torque, power and power factor. In Figure 3, users enter motor data such as: • • • • •

motor class. A, B, C, or D. motor rated power, in KVA, HP or shaft KW; motoe synchronous speed, full load speed, (RPM) and load shaft speed; motoe and load moments of inertia; Select “Equivalent Circuit” method or “Testing Curves” method.

As it can be seen, the program allows the user to specify or calculate the motor design class according to NEMA conventions. NEMA classifies induction motors according to the following categories, which are based on the ratio of X1 to X2 (X1/X2): • • •

Class A Class B Class C

X1/X2 = 1 X1/X2 = 2/3 X1/X2 = 3/7

EDSA induction motor parameter estimation provides four options: • • • •

Class A applies to: User defined NEMA class A Class B applies to: User defined NEMA class B Class C applies to: User defined NEMA class C Class D applies to: User defined as NEMA class “not known”. When class D is selected, the program will automatically determine the motor’s NEMA class based on the data provided by the user.

The moments of inertia can be entered or estimated. The equivalent circuit method supports the following motor assisted-starting (Motor Starting Controllers) methods:

‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰ ‰

Full Voltage Full Voltage Square - with three types of control, which are function of Time, % Motor Voltage and %Motor Speed. Wye-Delta - with three types of control. This controller switches the motor from star connected to delta connected. Auto-Transformer - with three types of controls. The controller modifies the tap setting in up to two steps. Part Winding - with three types of control. The controller modifies the tap setting in up to five steps Series Resistance - with three types of control. The controller reduces the amount of series impedance in up to five steps Series Reactance - with three types of control. This controller reduces the amount of series reactance in up to five steps. Shunt Capacitance - with three types of control. This controller reduces the amount of supplied reactive power in up to five steps. Solid State Voltage Control - with three control types. This controller reduces the tap setting in up to five steps. Solid State Current Limit - the controller sets the motor’s current limit to the specified current value. Solid State Current Ramp - it increases the current gradually from the first value to the end value over the Tramp (Time2 – Time 1). Solid State Voltage Ramp - this controller increases the voltage gradually from the first value to the end value over the Tramp (Time2 – Time 1). Solid State Torque Ramp - this controller increases the torque gradually from the first value to the end value over the Tramp (Time2 – Time 1). Variable Frequency Drive – the controller increases the frequency in steps. 4

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‰

VFD with constant V/Hz - the controller increases the frequency in steps, while maintain the ratio of voltage to Frequency constant to the specified value.

The above motor assisted-starting options cover a wide variety of the recent solid-state motor starting controls as well as the most traditionally used starting methods. The main objective behind the use of assisted-starting methods is to control (limit) the impact of motor starting events on the electrical power systems. Data requirements for each of the above motor assist starting options are on “Motor Start” tab of the “Motor Dynamic Information” dialog box. For example, the data and functionality of the “Solid State Voltage Control” are summarized in Figure 4. This figure shows the screen corresponding to input data for motor starting. The “Control Type” can be set to any of the following options: time, speed or motor bus voltage. In this example, motor 10 will be started. Time is selected to be control type. The user also needs to input rated voltage (KV), rated efficiency (%), rated power factor (%), synchronous speed (RPM), etc. as shown. A motor can also be started in two stages with different starter in each stage. We do not use the second starter here, so we put 999 seconds for switchover to Stage 2.

Figure 4: Motor Starter Data Dialog

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In the “Equivalent Circuit” tab of the “Motor Dynamic Information” dialog box (Figure 5), the user can enter the motor parameters and load torque (in per cent or actual units). The user should enter the motor’s equivalent electrical parameters; if this data are not known, then the user selects “Calculate” button, and the program calculates the motor parameter based on starting information and weighting factors (Figure 6).

Figure 5: Equivalent Circuit Method Data Dialog

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Figure 6: For calculating Equivalent Circuit Parameter

The weighting factors can be assigned for the following motor parameters: • • • •

Current Torque Power Factor Efficiency

A weighting factor applied to any of the above parameters is a number between 0.1 and 1. This number represents the degree of confidence the user has on the accuracy of the particular figure being entered. The program offers full automatic on-screen conversion between the different power units. In addition to the above basic input data, the user may specify a number of operating points – motor characteristics, as a function of speed. The sample points provided by the user can be sparse, in other words, the user does not need to have all the data for all the included operating points. For example, at speed zero (slip=1) the user may have the knowledge of the motor power factor and starting current but not of the electrical torque and efficiency. You may also use EDSA Motor Parameter Estimation program to calculate the motor equivalent circuit parameters.

3.2 Motor Starting Using Motor Equivalent Circuit The motor starting analysis can be performed by using either motor equivalent circuit impedances (rotor and stator), or the motor characteristics (current, torque, etc.) at different speeds. In the former case, the user should provide the rotor and stator impedances as shown in Figure 5 and Figure 6. The Equivalent circuit of the motor is shown in Figure 7. The power flow program computes the motor equivalent impedance based on:

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R2 ( s ) + jX 2 ( s )] * jX m s = + R1 + jX 1 R2 ( s ) + jX 2 ( s ) + jX m s [

Z mot

Figure 7: Equivalent Circuit Motor Model The motor equivalent impedance (recall that rotor resistance and reactance are assumed to be function of speed according to cage factors defined) is then placed at the motor bus similar to a shunt and power flow is solved. At every power flow solution, the motor rotational equation (also referred to as swing equation) shown below is also solved to compute the subsequent motor speed in time.

dw 2* H * = Te − Tm dt 3.3 Motor Starting Using Motor Testing Characteristics/SKVA The power flow program also supports the motor starting using the motor characteristics provided at different speed intervals (this is also known as SKVA method). These characteristics are kVA, power factor, electrical and load torques as shown in Figure 8 and are normally provided by the motor manufacturer from either field-testing or via mathematical motor modeling. The user may specify up to 100 points of data and save the characteristics into the library, or retrieve the data points from the library. The power flow program will not attempt to compute the individual motor impedances (rotor and stator) in this method, but rather will compute the total equivalent impedance from the kVA and power factor information. The electrical torque and kVA are of course adjusted according to:

Te = Te ( given) *V 2

kVA = kVA( given) * V

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Figure 8:Defining Motor Characteristics as a Function of Speed

3.4 Assessing Adequacy of Motor Electrical Torque and Load Torque Curve Fitting This motor starting solution allows the user to quickly assess the electrical torque that the motor can develop from the motor data provided. This feature facilitates the selection of a particular motor design based on the load torque requirements. The program takes into account any motor starter that the user has specified or alternatively, performs the analysis for full voltage start. For example, in the screen below, the data for one induction motor have been specified and starter type of “Variable Frequency Drive” has been defined. To see the developed electrical torque, select “Torque Fitting” as shown in Figure 9.

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Figure 9: Selecting Electrical Torque Assessment and Load Torque Fitting Option

The program, then, quickly performs the motor starting and displays the result of electrical torque and load torque as shown in Figure 10. The load torque can be adjusted by changing the coefficients A0-A3. To examine electrical torque for different motor parameters, modify the motor impedances shown in Figure 11 and repeat the same process again until the desired performance is achieved.

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Figure 10: Motor Start Testing and Load Torque Curve Fitting

3.5 Motor Decrement Export Function from Advanced Motor Starting to Protective Device Coordination In this version, you can run EDSA Advanced Motor Starting , then export the time-current to *.csv/Excel, then import the motor time current from *.csv into EDSA Equipment folder. Once the data are in the folder, then you can go to Protective Device Coordination, bring up the Motor/Load and apply Fuse, Relay, Breaker and perform a complete coordination. See the steps below. First, you will need to open a job file. Go to File Æ Open Drawing File, then go to Samples\Transient and open Loadramp.axd.

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Then select

in EDSA Advanced Motor Starting. You will see the following screen on the next page.

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Review the tabs. Make sure all the data are entered accordingly.

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Follow the steps as indicated and make sure to select “Power Source Impedance” option. Run the Advanced Motor Start by pressing “OK”.

View Curves, view Text Output then export to Excel. Once you click on “Export to Excel” you will see the following screen:

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Make sure the Unit Selection is “Actual”.

Next, give the motor a name. In this case, we will name the motor “Motor_Starting”. Next, select “View Curves Graphically”.

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Test all the functions and options and view the Motor Inrush Current.

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Follow the steps shown above. Next you will see the following screen:

Select File.

To open the saved Motor file, go to File as shown above.

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Select “Import From CSV File”.

Select Import from Excel as shown above.

Select the folder where you had saved or exported the motor in Excel format. In this case, select the Transient folder.

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Select the Motor from Folder

Enter the data for both Description and Curves.

Edit and complete the motor data information, as shown above.

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Next, review the Motor in-rush current and make sure it appears satisfactory.

Next, open the Standalone Protective Device Coordination by clicking the icon screen:

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. You will see the following

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1. 2. 3.

1. Select Motor 2. Select Custom Motor 3. Go to the manufacturer and select the motor that was imported from Advanced Motor Starting.

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4.

5.

6.

4. Complete the data for Equipment Voltage and Design Load Amps. 5. Next complete the data for Short Circuit Amps and short circuit symbol. Be sure to use Auto Select.

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1. 2.

Once the selection is complete and successful, you may save it and then proceed to select a device such as Relay, Fuse, Breaker, etc., for Coordination.

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In this case, a GE Relay was selected. View the coordination above.

4. Simultaneous Multi-Motor Starting Snapshots The program in this method runs three load flows: Before Starting, During Starting and After Starting. Voltage dip is defined as: Voltage Dip = V(Before) - V(During) (Volts) or Voltage Dip = 100 · ( V(Before) - V(During) ) / V(Before) (%)

(1)

A motor is treated as a load in the load flow calculation. For Before Starting condition, the motor load is 0.0; for the After Starting condition the motor load is equal to the motor normal running load and for the During Starting condition the motor load is equal to the motor normal running load times the NEMA factor, which is defined as the ratio of locked rotor motor starting current over the motor normal running current. The following figure shows the input data of NEMA and Lock Rotor Amps.

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The motor load can be modeled as constant KVA, constant current or constant Z load. For induction motor starting, it is recommended that the constant Z load type be used. There are also different motor starter types to choose in this method as shown in the following figure (Figure 11).

Figure 11: Motor “Motor Start” dialog box

The following equations are used for motor load calculation:

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where, HP is the motor horse power; PF power factor; LRAmps motor locked rotor current. For different motor starters, the motor starting inrush KVA is multiplied by a factor, called tap setting. For example, for an autotransformer 80% starter, the tap setting (multiplying factor) is 64%. The starting inrush KVA is calculated as follows: KVA(starting,AutoXfr80%) = 0.64 · KVA(starting,FullVolt)

(6)

The following is an example of motor starting output, where the voltage Before, During and After are shown in Volts and voltage dip in %.

Bus Name -----------------------01 02 03 04 05 06 07 08 09 Starting motor 11

System V (PU) V (PU) VDip V (PU) Type Volts Before During % After StartMethod ------ ------- -------- -------- ----- -------- -----------Swing 16500 1.0000 0.9973 0.27 1.0000 Gen 18000 1.0250 1.0233 0.17 1.0250 Gen 13800 1.0250 1.0238 0.11 1.0250 None 230000 0.9950 0.9921 0.30 0.9950 P_Load 230000 0.9719 0.9684 0.36 0.9719 P_Load 230000 0.9894 0.9866 0.28 0.9894 None 230000 1.0191 1.0151 0.39 1.0188 P_Load 230000 1.0091 1.0058 0.32 1.0090 None 230000 1.0260 1.0239 0.20 1.0259 Z_Load 4160 1.0191 0.9692 4.89 1.0126 FullVoltage P_Load 4160 1.0205 1.0184 0.21 1.0204

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APPENDIX A: Dynamic Motor Start Tutorial

Motor to be started

Figure 12: Network under study Figure 12 shows the network topology that will be used for the study. The motor to be started is recognized by the system as bus id 10, and it is clearly marked in the above figure. The motor characteristics are as follows: Rated Voltage: Rated HP: Efficiency: Run PF: Start PF: LRA/FLA: LR Amps:

4,160 Volts 1000 HP 96% 85% 25% 5.0 632.5 Amps

This tutorial exercise will illustrate, step-by-step, how to perform motor starting analysis using the following methods: 1. 2. 3. 4. 5. 6.

Full Voltage Solid-State Voltage Control Solid-State Current Limit Solid-State Current Ramp Solid-State Voltage Ramp Solid-State Torque Ramp

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The full voltage method will calculate the worst-case scenario, which can then be compared with the other five Solid-State starting methods. The specific results for rest of the starters can be obtained from Table 1 of this tutorial.

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Motor Start Summary Results

The table below summarizes the motor acceleration time and voltage recovery based on starting method. Table 1: Results comparison between the different motor starting methods. Starting Method

Full Voltage Solid State Voltage Control Solid State Current Limit Solid State Current Ramp Solid State Voltage Ramp Solid State Torque Ramp

Acceleration Time (Sec)

% Initial Starting Volt

% Min Motor Volt

6.00 8.27 8.35 6.10 7.35 6.00

99.6 49.8 85.7 85.7 59.8 99.6

95.7 49.3 85.7 85.7 58.9 95.7

% Restorted Motor Volt 99.1 99.1 99.1 99.1 99.1 99.1

% Max Torque 199.16 198.50 199.28 199.32 198.54 199.16

% Motor Operating Slip 1.2 1.2 1.2 1.2 1.2 1.2

From the above table the user can simulate the motor starting using various starter controller and select the appropriate controller type for his application. Note: The series reactance, Series Resistance, Shunt Capacitance, Wye-Delta, Part Winding, and Auto Transformer controllers have speed and Voltage Control function options in addition to the time option. While real controllers may not actually have Speed or Voltage type controls in a motor starting mode, these additional functions are included to help the user determine the correct time at which the motor will reach a particular speed. The user can run the study to determine the time, and then re-run the study with the correct time based on speed and voltage.

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A Tutorial No. 1: Full Voltage Start A.1 Open the pre-built file named “Loadramp.axd”. Once the file has been loaded, proceed to set the motor Bus 10 into the started mode and get the “motor Dynamic Information” dialog box as shown in the following screen picture.

Step2. Select “Motor Dynamic Information” dialog box button.

Step 1. Double-click and set the motor as “To be Started”.

Figure 13: Set Starting Motor

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A.2 Enter all the relevant data that pertains to the Motor Starting method and the Motor itself. Proceed as indicated in the following screen capture (Figure 14 ~ 16).

Step 1. On the “General” tab, select the starting motor

Step 2. Enter an appropriate description and data. Make sure “Equivalent Circuit” is selected.

Figure 14: General Motor Dynamic Data

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Step3. On “Motor Starter” tab, select “Full Voltage” as the starting method.

Figure 15: Motor Starter Selection

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Step 4: Enter the motor’s equivalent network parameters here. If the data are not known, select “Calculate” to have the program estimate these values from the data entered on “General” tab or “Testing Curves” tab.

Step 5. Enter up to 5 points of the Speed – Torque characteristic of the motor. The “Torque Fitting” will show you the curves, so you can see visually if the data entered are OK and can make adjustment accordingly.

Step 6. Select “OK”.

Figure 16: Equivalent Circuit Parameters and Load Torque

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A.3 Enter information in the options dialog and then click “Analyze” button to do the calculation as shown in the following screen pictures (Figure 17 ~ 18).

“Options” and “Analyze”

Figure 17: Motor Starting Tool Bar

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Select “Individual Dynamic Motor Start method.

Figure 18: Motor Starting Options

A.4 Select the “Analyze” button to complete the analysis and then select Report Manger to view results.

Report Manager icon.

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Result reports

Figure 19: Motor Start Report Manager

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Summary text result: EDSA Advanced Motor Starting Program v4.20.00 ============================================= Project No. : Project Name: Title : Drawing No. : Revision No.: Jobfile Name: LOADRAMP Scenario :

Page Date Time Company Engineer Check by Date

: 1 : 10/16/2008 : 00:10:04 pm : : : :

Starting Motor Name : 10 Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor

NEMA Design Class Rated Power Rated Voltage Rated Power Factor Rated Efficiency Synchronous Speed Rated Shaft Speed Moment of Inertia Inertia Constant Rated Torque Rated Current

: = = = = = = = = = =

B 914.216 KVA 4.160 KV 85.00 % 96.00 % 3600 RPM 3546 RPM 200.00 lb-ft sq 0.64 sec. 1481.73 lbf-ft 126.88 Ampere

Load Shaft Speed Load Moment of Inertia Load Inertia Constant

= 3546 RPM = 50.00 lb-ft sq = 0.16 sec.

Include Power Source Impedance Simulation Method

: Yes : Equivalent Circuit

Motor Motor Motor Motor Motor Motor Motor Motor

= = = = = = = =

Stator Resistance Stator Reactance Rotor Resistance Rotor Reactance Magnetization Resistance Magnetization Reactance Rotor Resistance Cage Factor Rotor Reactance Cage Factor

0.400 Ohms 2.000 Ohms 0.290 Ohms 2.710 Ohms 6318.000 Ohms 54.940 Ohms 0.104 0.000

Load Name in Library : Loadramp Speed (%) Load Torque (%) 0.00 0.00 20.00 4.00 40.00 16.00 60.00 36.00 90.00 81.00 Motor Start Type at Stage 1: Full Voltage Switch to Stage 2 at 999.00 seconds Motor Start Type at Stage 2: Full Voltage Simulation Results ================== Total Acceleration Time Motor Operating Slip Maximum (Breakdown) Torque Initial Starting Voltage Minimum Motor Voltage Restored Motor Voltage

= = = = = =

39

6.00 Sec. 1.20 % 199.16 % 99.60 % = 4.143 KV 95.70 % = 3.981 KV 99.10 % = 4.123 KV

Advanced Motor Starting Analysis

Graphic result:

B Tutorial No. 2: Solid State Voltage Control B.1 In this tutorial, the same motor used in tutorial No. 1, will be started using a Solid State Voltage controlled starter. The starting process will be ramped up in two time-based steps as follows: Step 1-

Time: Voltage:

0.0 sec 0.5 PU

Step 2-

Time: Voltage:

3.0 sec 1.0 PU

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Step 1: Select “Solid State Voltage Control”, and select “Time (sec.)”

Step 2: Enter the required voltage control stages here.

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B.2 Select the “Analyze” button to complete the analysis and then select Report Manger to view results. Summary text result: EDSA Advanced Motor Starting Program v4.20.00 ============================================= Project No. : Project Name: Title : Drawing No. : Revision No.: Jobfile Name: LOADRAMP Scenario :

Page Date Time Company Engineer Check by Date

: 1 : 10/16/2008 : 03:22:30 pm : : : :

Starting Motor Name : 10 Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor

NEMA Design Class Rated Power Rated Voltage Rated Power Factor Rated Efficiency Synchronous Speed Rated Shaft Speed Moment of Inertia Inertia Constant Rated Torque Rated Current

: = = = = = = = = = =

B 914.216 KVA 4.160 KV 85.00 % 96.00 % 3600 RPM 3546 RPM 200.00 lb-ft sq 0.64 sec. 1481.73 lbf-ft 126.88 Ampere

Load Shaft Speed Load Moment of Inertia Load Inertia Constant

= 3546 RPM = 50.00 lb-ft sq = 0.16 sec.

Include Power Source Impedance Simulation Method

: Yes : Equivalent Circuit

Motor Motor Motor Motor Motor Motor Motor Motor

= = = = = = = =

Stator Resistance Stator Reactance Rotor Resistance Rotor Reactance Magnetization Resistance Magnetization Reactance Rotor Resistance Cage Factor Rotor Reactance Cage Factor

0.400 Ohms 2.000 Ohms 0.290 Ohms 2.710 Ohms 6318.000 Ohms 54.940 Ohms 0.104 0.000

Load Name in Library : Loadramp Speed (%) Load Torque (%) 0.00 0.00 20.00 4.00 40.00 16.00 60.00 36.00 90.00 81.00 Motor Start Type at Stage 1: Solid State Voltage Control Time (Sec.) : 0.000 3.000 Tap (pu) : 0.500 1.000 Switch to Stage 2 at 999.00 seconds Motor Start Type at Stage 2: Full Voltage Simulation Results ================== Total Acceleration Time Motor Operating Slip Maximum (Breakdown) Torque Initial Starting Voltage Minimum Motor Voltage Restored Motor Voltage

= = = = = =

8.27 Sec. 1.20 % 198.50 % 49.80 % = 2.072 KV 49.30 % = 2.051 KV 99.10 % = 4.123 KV

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Graphic Result:

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C Tutorial No. 3: Solid State Current Limit C.1 In this tutorial, the same motor used in tutorial No. 1, will be started using a Solid State Current Limited starter. The starting process will limit the starting current to a maximum value of 3.5 PU, as shown in the following screen picture:

Step 1: Select “Solid State Current Limit”.

Step 2: Enter the required current limitation factor here.

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Advanced Motor Starting Analysis

C.2 Select the “Analyze” button to complete the analysis and then select Report Manger to view results. Summary text result: EDSA Advanced Motor Starting Program v4.20.00 ============================================= Project No. : Project Name: Title : Drawing No. : Revision No.: Jobfile Name: LOADRAMP Scenario :

Page Date Time Company Engineer Check by Date

: 1 : 10/16/2008 : 03:39:12 pm : : : :

Starting Motor Name : 10 Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor

NEMA Design Class Rated Power Rated Voltage Rated Power Factor Rated Efficiency Synchronous Speed Rated Shaft Speed Moment of Inertia Inertia Constant Rated Torque Rated Current

: = = = = = = = = = =

B 914.216 KVA 4.160 KV 85.00 % 96.00 % 3600 RPM 3546 RPM 200.00 lb-ft sq 0.64 sec. 1481.73 lbf-ft 126.88 Ampere

Load Shaft Speed Load Moment of Inertia Load Inertia Constant

= 3546 RPM = 50.00 lb-ft sq = 0.16 sec.

Include Power Source Impedance Simulation Method

: Yes : Equivalent Circuit

Motor Motor Motor Motor Motor Motor Motor Motor

= = = = = = = =

Stator Resistance Stator Reactance Rotor Resistance Rotor Reactance Magnetization Resistance Magnetization Reactance Rotor Resistance Cage Factor Rotor Reactance Cage Factor

0.400 Ohms 2.000 Ohms 0.290 Ohms 2.710 Ohms 6318.000 Ohms 54.940 Ohms 0.104 0.000

Load Name in Library : Loadramp Speed (%) Load Torque (%) 0.00 0.00 20.00 4.00 40.00 16.00 60.00 36.00 90.00 81.00 Motor Start Type at Stage 1: Solid State Current Limit Current (pu) : 3.50 Switch to Stage 2 at 999.00 seconds Motor Start Type at Stage 2: Full Voltage Simulation Results ================== Total Acceleration Time Motor Operating Slip Maximum (Breakdown) Torque Initial Starting Voltage Minimum Motor Voltage Restored Motor Voltage

= = = = = =

8.35 Sec. 1.20 % 199.28 % 85.70 % = 3.565 KV 85.70 % = 3.565 KV 99.10 % = 4.123 KV

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Advanced Motor Starting Analysis

Graphic Result:

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Advanced Motor Starting Analysis

D Tutorial No. 4: Solid State Current Ramp D.1 In this tutorial, the same motor used in tutorial No. 1, will be started using a Solid State Current Ramp controlled starter. The starting process will be ramped up in two points as follows: Point 1-

Time: Current:

0.0 sec 3.5 PU

Point 2-

Time: Current:

3.0 sec 5.0 PU

Step 1: Select “Solid State Current Ramp”.

Step 2: Enter the required current ramp stages here.

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Advanced Motor Starting Analysis

D.2 Select the “Analyze” button to complete the analysis and then select Report Manger to view results. Summary text result: EDSA Advanced Motor Starting Program v4.20.00 ============================================= Project No. : Project Name: Title : Drawing No. : Revision No.: Jobfile Name: LOADRAMP Scenario :

Page Date Time Company Engineer Check by Date

: 1 : 10/16/2008 : 04:05:31 pm : : : :

Starting Motor Name : 10 Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor

NEMA Design Class Rated Power Rated Voltage Rated Power Factor Rated Efficiency Synchronous Speed Rated Shaft Speed Moment of Inertia Inertia Constant Rated Torque Rated Current

: = = = = = = = = = =

B 914.216 KVA 4.160 KV 85.00 % 96.00 % 3600 RPM 3546 RPM 200.00 lb-ft sq 0.64 sec. 1481.73 lbf-ft 126.88 Ampere

Load Shaft Speed Load Moment of Inertia Load Inertia Constant

= 3546 RPM = 50.00 lb-ft sq = 0.16 sec.

Include Power Source Impedance Simulation Method

: Yes : Equivalent Circuit

Motor Motor Motor Motor Motor Motor Motor Motor

= = = = = = = =

Stator Resistance Stator Reactance Rotor Resistance Rotor Reactance Magnetization Resistance Magnetization Reactance Rotor Resistance Cage Factor Rotor Reactance Cage Factor

0.400 Ohms 2.000 Ohms 0.290 Ohms 2.710 Ohms 6318.000 Ohms 54.940 Ohms 0.104 0.000

Load Name in Library : Loadramp Speed (%) Load Torque (%) 0.00 0.00 20.00 4.00 40.00 16.00 60.00 36.00 90.00 81.00 Motor Start Type at Stage 1: Solid State Current Ramp Time (Sec.) : 0.00 3.00 Current (pu) : 3.500 5.000 Switch to Stage 2 at 999.00 seconds Motor Start Type at Stage 2: Full Voltage Simulation Results ================== Total Acceleration Time Motor Operating Slip Maximum (Breakdown) Torque Initial Starting Voltage Minimum Motor Voltage Restored Motor Voltage

= = = = = =

6.10 Sec. 1.20 % 199.32 % 85.70 % = 3.565 KV 85.70 % = 3.565 KV 99.10 % = 4.123 KV

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Advanced Motor Starting Analysis

Graphic Result:

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Advanced Motor Starting Analysis

E Tutorial No. 5: Solid State Voltage Ramp E.1 In this tutorial, the same motor used in tutorial No. 1, will be started using a Solid State Voltage Ramp controlled starter. The starting process will be ramped up in two points as follows: Point 1-

Time: Voltage:

0.0 sec 0.6 PU

Point 2-

Time: Voltage:

3.0 sec 0.9 PU

Step 1: Select “Solid State Voltage Ramp”.

Step 2: Enter the required voltage ramp stages here.

E.2 Select the “Analyze” button to complete the analysis and then select Report Manger to view results. 50

Advanced Motor Starting Analysis

Summary text result: EDSA Advanced Motor Starting Program v4.20.00 ============================================= Project No. : Project Name: Title : Drawing No. : Revision No.: Jobfile Name: LOADRAMP Scenario :

Page Date Time Company Engineer Check by Date

: 1 : 10/16/2008 : 04:17:48 pm : : : :

Starting Motor Name : 10 Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor

NEMA Design Class Rated Power Rated Voltage Rated Power Factor Rated Efficiency Synchronous Speed Rated Shaft Speed Moment of Inertia Inertia Constant Rated Torque Rated Current

: = = = = = = = = = =

B 914.216 KVA 4.160 KV 85.00 % 96.00 % 3600 RPM 3546 RPM 200.00 lb-ft sq 0.64 sec. 1481.73 lbf-ft 126.88 Ampere

Load Shaft Speed Load Moment of Inertia Load Inertia Constant

= 3546 RPM = 50.00 lb-ft sq = 0.16 sec.

Include Power Source Impedance Simulation Method

: Yes : Equivalent Circuit

Motor Motor Motor Motor Motor Motor Motor Motor

= = = = = = = =

Stator Resistance Stator Reactance Rotor Resistance Rotor Reactance Magnetization Resistance Magnetization Reactance Rotor Resistance Cage Factor Rotor Reactance Cage Factor

0.400 Ohms 2.000 Ohms 0.290 Ohms 2.710 Ohms 6318.000 Ohms 54.940 Ohms 0.104 0.000

Load Name in Library : Loadramp Speed (%) Load Torque (%) 0.00 0.00 20.00 4.00 40.00 16.00 60.00 36.00 90.00 81.00 Motor Start Type at Stage 1: Solid State Voltage Ramp Time (Sec.) : 0.00 3.00 Voltage (pu) : 0.600 0.900 Switch to Stage 2 at 999.00 seconds Motor Start Type at Stage 2: Full Voltage Simulation Results ================== Total Acceleration Time Motor Operating Slip Maximum (Breakdown) Torque Initial Starting Voltage Minimum Motor Voltage Restored Motor Voltage

= = = = = =

7.35 Sec. 1.20 % 198.54 % 59.80 % = 2.488 KV 58.90 % = 2.450 KV 99.10 % = 4.123 KV

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Advanced Motor Starting Analysis

Graphic Result:

F Tutorial No. 6: Solid State Torque Ramp F.1 In this tutorial, the same motor used in tutorial No. 1, will be started using a Solid State Torque Ramp controlled starter. The starting process will be ramped up in two points as follows: Point 1-

Time: Torque:

0.0 sec 0.7 PU

Point 2-

Time: Torque:

3.0 sec 2.0 PU

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Advanced Motor Starting Analysis

Step 1: Select “Solid State Torque Ramp”.

Step 2: Enter the required torque ramp stages here.

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Advanced Motor Starting Analysis

F.2 Select the “Analyze” button to complete the analysis and then select Report Manger to view results. Summary text result: EDSA Advanced Motor Starting Program v4.20.00 ============================================= Project No. : Project Name: Title : Drawing No. : Revision No.: Jobfile Name: LOADRAMP Scenario :

Page Date Time Company Engineer Check by Date

: 1 : 10/16/2008 : 04:28:12 pm : : : :

Starting Motor Name : 10 Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor Motor

NEMA Design Class Rated Power Rated Voltage Rated Power Factor Rated Efficiency Synchronous Speed Rated Shaft Speed Moment of Inertia Inertia Constant Rated Torque Rated Current

: = = = = = = = = = =

B 914.216 KVA 4.160 KV 85.00 % 96.00 % 3600 RPM 3546 RPM 200.00 lb-ft sq 0.64 sec. 1481.73 lbf-ft 126.88 Ampere

Load Shaft Speed Load Moment of Inertia Load Inertia Constant

= 3546 RPM = 50.00 lb-ft sq = 0.16 sec.

Include Power Source Impedance Simulation Method

: Yes : Equivalent Circuit

Motor Motor Motor Motor Motor Motor Motor Motor

= = = = = = = =

Stator Resistance Stator Reactance Rotor Resistance Rotor Reactance Magnetization Resistance Magnetization Reactance Rotor Resistance Cage Factor Rotor Reactance Cage Factor

0.400 Ohms 2.000 Ohms 0.290 Ohms 2.710 Ohms 6318.000 Ohms 54.940 Ohms 0.104 0.000

Load Name in Library : Loadramp Speed (%) Load Torque (%) 0.00 0.00 20.00 4.00 40.00 16.00 60.00 36.00 90.00 81.00 Motor Start Type at Stage 1: Solid State Torque Ramp Time (Sec.) : 0.00 3.00 Torque (pu) : 0.700 2.000 Switch to Stage 2 at 999.00 seconds Motor Start Type at Stage 2: Full Voltage Simulation Results ================== Total Acceleration Time Motor Operating Slip Maximum (Breakdown) Torque Initial Starting Voltage Minimum Motor Voltage Restored Motor Voltage

= = = = = =

6.00 Sec. 1.20 % 199.16 % 99.60 % = 4.143 KV 95.70 % = 3.981 KV 99.10 % = 4.123 KV

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Advanced Motor Starting Analysis

Graphic Result:

55

Advanced Motor Starting Analysis

APPENDIX B: Simultaneous Multi-Motor Starting Snapshots method Tutorial G Network under Study

Figure 20: Network under Study (File name: MX339.Axd)

The purpose of this tutorial exercise is to illustrate the steps required to run a Motor Starting Analysis using the Simultaneous Multi-Motor Starting Snapshots method. Additionally, this exercise will be used to verify the validity of EDSA's calculations versus the motor starting analysis example described in IEEE std. 399-1997, pages 244 to 253. The EDSA one line diagram was shown in Figure 20. The impedances provided in the IEEE example are expressed in per-unit on a 100 MVA base. In the tutorial example, a base of 100 MVA has also been used for the purpose of consistency. In addition, the network was modeled as follows: 1.

Branches of negligible impedance were added to Load 1, Load 2 and the Motor under study.

2.

For the 1000 HP motor, a running power factor of 0.85 and efficiency of 0.88 is assumed. Since it is assumed that 1 kVA = 1HP (Reference IEEE 399-1997 Page 240 Section 9.5.2), then, EFF*PF = 0.746 56

Advanced Motor Starting Analysis

In EDSA, PF* EFF = 0.85 * 0.88 = 0.748 and the FLA is equal to:

FLA =

1000 = 138.786 amps then, LRA = 6 x FLA = 832.72 amps 4.16 3

3.

The network was modeled as shown in Figure 20 and as defined in IEEE 399-1997, Section 9.6.3, pages 243 to 250. From a Short Circuit point of view, the generator was modeled as an 115kV, 12MVA unit with a 15% transient reactance (refer to page 249, Section 9.6.3 of the standard). These values, translate to a reactance of 1.25 pu on the 100 MVA base. From the Load Flow point of view, the generator has been defined as swing bus.

4.

As illustrated in the IEEE std. 399-1997, the driving EMF within the generator (behind the transient reactance) was modeled as an ideal source of 1.0564 Volts pu. This causes the voltage at the physical terminals of the generator to be 1.0 pu, as a result of the voltage drop across the source's short circuit impedance. This tutorial will demonstrate that it is not necessary to resort to this additional modeling effort in order to account for the effect of the source impedance. EDSA Motor Starting includes an option whereby the user can choose to include the source impedance in the motor starting calculations. Once this option is selected, the program will automatically create the driving EMF required for the calculations inside the program. One of the advantages of this feature is that it saves time and avoids confusion by keeping the original single line diagram intact. G.1 Enter Input Data G.1.1

Generator Data

After opening the project file (Figure 20), select the Generator bus (Bus 1) and double-click it with the left mouse button. The editor dialog box (Figure 21) comes out. As can be seen in the generator editor screen capture, the 12 MVA generator was modeled as a source with a reactance of 1.25 pu on the defined basis of 100 MVA and 115 kV. In order to compare the values obtained from this tutorial with those calculated by the IEEE std. 399-1997, an angle of -4.1 degrees was assigned to the generator. Remember that a fictitious swing bus (bus 99) was used to model the ideal driving EMF of the source in the IEEE std. 399-1997. Since the IEEE std. 399-1997 assigned an angle of 0 degrees to this bus, we must compensate by displacing the angle at our generator terminals by an amount such that it will yield a 0-degree angle on the program's internal swing bus. The angle field is on the Load Flow tab as shown in Figure 22.

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Advanced Motor Starting Analysis

Figure 21: Generator Data

Figure 22: Generator Voltage Angle 58

Advanced Motor Starting Analysis

G.1.2

Motor Data

Double click the Motor bus (Bus 6) shown in Figure 20, the motor editor comes out. Make sure the “To Be Started” button under Motor Start tab is on, the Motor Starter Type is Full Voltage, the Motor Load Type is Constant Z and the Tap Setting is 100%, as shown in Figure 23.

Figure 23: Motor Data under Motor Start

Under Short Circuit tab, the Motor Rating is 1000 HP, the Efficiency is 88 %, the Power Factor is 85 %, the Starting PF field type 15 %, the LR Amps (locked rotor amps) field reads 832.72 Amps, as shown in Figure 24.

Figure 24: Motor Data under Short Circuit

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Advanced Motor Starting Analysis

G.2 Motor Starting Analysis Results

Figure 25: Motor Starting Options In motor starting options dialog box (Figure 25), select Simultaneous Multi-Motor Starting Snapshots method and for “Include Power Source Z”, select X”, which causes the program to include the 1.25pu source short circuit impedance in the voltage drop calculations. Select “Analyze” to complete the analysis. The text result will automatically come out if the “Auto Text Report” in Figure 25 is checked, or select the report manager as shown in Figure 26.

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Advanced Motor Starting Analysis

Report Manager

Motor Starting Text Report and Summary Report

Figure 26: Report Manager

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Advanced Motor Starting Analysis

Motor starting text report and summary report are shown below.

EDSA Advanced Motor Starting Program v4.20.00 ============================================= Project No. : Project Name: Title : Drawing No. : Revision No.: Jobfile Name: MX339 Scenario :

Page Date Time Company Engineer Check by Date

: 1 : 10/20/2008 : 11:41:55 am : : : :

Starting Motor Info =================== System Running Load Start LRA Bus Name Type Volts kVA PF(%) PF(%) Amps MF StartMethod ------------------------ ------ ------- --------- ------ ------ -------- ----- -----------MOTOR 1 Z_Load 4160 997.33 85.00 15.00 832.72 6.02 FullVoltage

Power Source Internal Impedance =============================== Bus Name Type R (Ohm) X (Ohm) ------------------------ ------ -------- -------BUS 1 Swing 0.0000 165.3125

Bus Voltage Result ==================

Bus Name -----------------------BUS 1 BUS 2 BUS 3 BUS 4 LOAD 1 LOAD 2 MOTOR 1

System V (PU) V (PU) VDip V (PU) Type Volts Before During % After StartMethod ------ ------- -------- -------- ----- -------- -----------Swing 115000 1.0000 0.9292 7.08 1.0000 None 13800 0.9707 0.8655 10.84 0.9665 None 4160 0.9442 0.8353 11.53 0.9399 None 4160 0.9511 0.7939 16.52 0.9407 P_Load 4160 0.9442 0.8353 11.53 0.9399 P_Load 4160 0.9511 0.7939 16.52 0.9407 Z_Load 4160 0.9511 0.7939 16.52 0.9407 FullVoltage

Summary of Total Generation and Demand ======================================

Swing Bus(es): Generators : Shunt : Static Load Motor Load Total Loss

: : :

Mismatch

:

P(MW)

Q(MVAR)

S(MVA)

PF(%)

6.692 0.000 0.000

11.035 0.000 0.000

12.905 0.000 0.000

51.85 0.00 0.00

7.000 3.782

85.00 15.00

5.950 0.567 0.174 ---------0.000

3.687 3.739 3.608 ----------0.000

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Advanced Motor Starting Analysis

Following is a comparison table between the results obtained with EDSA and the results documented in the IEEE std.399-1997, page 253: Table 2: Comparison to IEEE Standard

BUS ID Bus 1 / Main Xfmr Pri Bus 2 / Main Xfmr Sec. Bus 3 / 5MVA Xfmr Sec. Bus 4 / Mtr Strt Bus ERROR

Voltage PU IEEE EDSA 0.929 0.929 0.865 0.865 0.835 0.835 0.794 0.794 0%

Tot. kW Loss IEEE EDSA 174

174 0%

Tot. kVAR Loss IEEE EDSA 3,608

3,608 0%

As indicated by the above figures, the EDSA Motor Starting program provides accurate results compared to the IEEE standard.

63