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    ETAP Workshop Notes ANSI Short Circuit Example: Description

    Uploaded by

    Ganti Kamesh
    This document provides instructions for running short-circuit studies in ETAP using an example power system. The example covers entering component data, creating configurations, setting up study cases, running device duty calculations, and verifying and sizing equipment ratings. The purpose is to understand the data required for short-circuit analysis and analyze the results to size protective devices.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    ETAP Workshop Notes ANSI Short Circuit Example: Description

    Uploaded by

    Ganti Kamesh
    139 views6 pages
    This document provides instructions for running short-circuit studies in ETAP using an example power system. The example covers entering component data, creating configurations, setting up study cases, running device duty calculations, and verifying and sizing equipment ratings. The purpose is to understand the data required for short-circuit analysis and analyze the results to size protective devices.

    Original Description:

    Original Title

    3.ANSI SC-Exercise

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    This document provides instructions for running short-circuit studies in ETAP using an example power system. The example covers entering component data, creating configurations, setting up study cases, running device duty calculations, and verifying and sizing equipment ratings. The purpose is to understand the data required for short-circuit analysis and analyze the results to size protective devices.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    139 views6 pages

    ETAP Workshop Notes ANSI Short Circuit Example: Description

    Uploaded by

    Ganti Kamesh
    This document provides instructions for running short-circuit studies in ETAP using an example power system. The example covers entering component data, creating configurations, setting up study cases, running device duty calculations, and verifying and sizing equipment ratings. The purpose is to understand the data required for short-circuit analysis and analyze the results to size protective devices.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 6
    At a glance
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    This example demonstrates how to perform short circuit analysis in ETAP including entering device data, creating configurations and study cases, running fault calculations, and sizing protective devices.

    The purpose of this example is to understand the impedance and ratings data required to run short-circuit analysis and covers 3-phase device duty calculations, unbalanced faults, and sizing of protective device equipment ratings.

    Study case FaultAll-B results in the worst short circuit current because it considers motor contribution based on motor status and loading category (design) and calculates fault on all buses.

    ETAP Workshop Notes

    ANSI Short Circuit Example


    Description
    This is an example to run short-circuit studies for a system with different configurations and operating
    conditions. The system contains the elements with most contributions towards short-circuit.

    Purpose
    The purpose of this example is to understand the impedance and ratings data required to run short-circuit
    analysis. This example covers 3-phase device duty and unbalanced short-circuit calculations plus it
    requires analysis of the results by inspection of the one-line results and reports. The final section of the
    exercise deals with the sizing and selection of protective device equipment ratings.

    Setup
    Load the project file named “SC-ANSI-Example-1” located under the directory Examples/SCExample1
    in Short-Circuit chapter of the workshop notes. Use the default ETAP library.

    Procedure

    1. Enter the following data to the components for SC calculations


    Element Parameters Location
    U1 3-phase: MVAsc = 2000, X/R = 55; 1-Phase: MVAsc = 1750, X/R = 48 OLV1 (Fig1)
    Gen1 & Subtransient Model, Round-Rotor, Use Typical Data; Xd” Tolerance = 5% OLV1 (Fig1)
    Gen3 (this option is in “Imp/Model” page)
    Syn1 Xd” = X2 = X0 = 15.38%, all X/R = 30.8 Network2 (Fig2)
    All Ind Mtr Use “Std MF” Option for ANSI SC Z (this option is in “Imp” page) Network2 (Fig2)
    Cmtr1 (Fig3)
    Lump Loads LRC = 650%, “High”; X/R = 15; Use “Std MF” option OLV1 (Fig1)
    XFMR T1: Tol% = 10; T2: Tol% = 7.5 OLV1 (Fig1)
    Cable* For all branch/equipment cables: Tmin = 25 °C, Tmax = 90 °C Network2 (Fig2)
    (these value are in “Impedance” page) Cmtr1 (Fig3)
    *Note: It may be easier to accomplish this from the SC study case.

    This document is confidential and proprietary to ETAP / ETAP Automation and may not be reproduced, published
    or disclosed to others without written authorization of ETAP / ETAP Automation. All Rights Reserved. Page 1 of 6
    ETAP Workshop Notes

    ANSI Short Circuit Example

    Figure 1: OLV1

    4x500 HP Figure2: Network2

    This document is confidential and proprietary to ETAP / ETAP Automation and may not be reproduced, published
    or disclosed to others without written authorization of ETAP / ETAP Automation. All Rights Reserved. Page 2 of 6
    ETAP Workshop Notes

    ANSI Short Circuit Example

    Figure 3: Cmtr1

    2. Create two configurations

    Configuration Setup
    Normal Open tie-CB CB1 and close all other CBs.
    T3 Down Close CB1 and open CBs on both sides of T3
    T4 Down Close CB1 and open CBs on both sides of T4

    3. Create and set up the following study cases: (If steps 1 and 2 have not been completed, please open
    project “SC-ANSI-Example-2”, otherwise, continue using project “SC-Example-1” for step 3).
    Study Case: FaultBus4
    Page Parameter Setting
    Info Adjust Base kV for XFMR Tap
    Do not consider cable/OL heater for motor
    Motor contribution based on motor status
    Fault only bus 4 – Report Contribution Level =3
    Standard Prefault voltage = 100% of bus nominal kV
    Use variable machine X/R
    HV CB interrupting rating adjusted based on nominal kV
    Device duty based on total bus fault current
    Calculation according to C37.010-1999
    LV MCCB & ICCB – Use “Higher MF” option
    Adjustment Individual XFMR Z tolerance, global cable R temperature at 25 °C
    Alert Marginal limit = 95%

    Study Case: FaultAll-A


    Page Parameter Setting
    Info Adjust Base kV for XFMR Tap
    Do not consider cable/OL heater for motor
    Motor contribution based on motor status
    Fault all buses – Report Contribution Level = 3
    Standard Prefault voltage = 102% of bus nominal kV

    This document is confidential and proprietary to ETAP / ETAP Automation and may not be reproduced, published
    or disclosed to others without written authorization of ETAP / ETAP Automation. All Rights Reserved. Page 3 of 6
    ETAP Workshop Notes

    ANSI Short Circuit Example


    Use fixed machine X/R
    HV CB interrupting rating adjusted based on nominal kV & Vf
    Device duty based on total bus fault current
    Calculation according to C37.010-1999
    LV MCCB & ICCB – Use “Higher MF” option
    Adjustment Individual XFMR Z tolerance, global cable R temperature at 25 °C
    Alert Marginal limit = 95%

    Study Case: FaultAll-B


    Page Parameter Setting
    Info Adjust Base kV for XFMR Tap
    Do not consider Cable/OL heater for Motor
    Motor contribution based on motor status and loading category
    (Design)
    Fault all buses – Report Contribution Level =3
    Standard Prefault voltage = Vmag * nominal kV
    Use fixed machine X/R
    HV CB interrupting rating adjusted based on nominal kV & Vf
    Device duty based on total bus fault current
    Calculation according to C37.010-1999
    LV MCCB & ICCB – Use “Higher MF” option
    Adjustment Individual XFMR Z tolerance, global cable R temperature at 25 °C
    Alert Marginal limit = 95%

    4. Run Device Duty calculation


    • Study Case – FaultBus4
    • Configuration – Normal, T3 Down, T4 Down
    • Run Device Duty Calculation
    • Check OLV display (Where and how can you set OLV display?)
    • Check report

    5. Run Device Duty calculation


    • Study Case – FaultAll-A
    • Configuration – Normal, T3 Down, T4 Down
    • Run Device Duty Calculation
    • Check OLV display – Compare OLV display against the one in 2.
    • Check report

    6. Run Device Duty calculation


    • Study Case – FaultAll-B
    • Configuration – Normal, T3 Down, T4 Down
    • Run Device Duty Calculation
    • Check OLV display

    This document is confidential and proprietary to ETAP / ETAP Automation and may not be reproduced, published
    or disclosed to others without written authorization of ETAP / ETAP Automation. All Rights Reserved. Page 4 of 6
    ETAP Workshop Notes

    ANSI Short Circuit Example


    • Check report

    Questions:
    • Which study case results in the worst SC current?
    • Which configuration results in the worst SC current?

    Verify and Size Equipment Rating


    1. Factors to be considered
    • System configuration – PD status and load configurations
    • Revision data
    • Study case – Vf, X/R, rating adjustment, etc

    2. Verify devices with existing settings


    • Bus – Bus1 and Bus7
    • PD – CB5, CB8, CB10, CB11, and CB23
    • Are there any problems with the existing settings? - If yes, fix them
    • Run SC with the configuration and study case that give the worst case

    3. Select rating/size for some devices


    • Bus –Bus5 and Bus6
    • PD – CBs connected to Bus5 and Bus6 (CB1, CB12, CB13, CB14, CB15, CB16)
    • Run SC with the configuration and study case that give the worst case

    Suggested Ratings for Some Components


    Element Parameters
    Bus5 & Bus6 Switchgear: 800? 58 kA, 97.88 kA

    CB1,12,13,14, 15, 16, 19 GE, VB-4.16-250, 4.76 kV, 1200 Amp,?, 29 kA

    4. Select rating/size for some devices


    • Bus –Bus3, and Bus8
    • PD – CBs connected to Bus1, and Bus7 Steps for device sizing:
    • Identify the worst SC case – combination of revision, configuration & study case
    • Run SC calculation for the case and determine fault current
    • Select a device size based on the fault currents
    • Run SC calculation again to verify device rating

    Suggested Ratings for Some Components


    Element Parameters
    Bus 3 Switchgear: 600 Amp? 37 kA, 62.44 kA
    Bus 8 MCC: 600 Amp? 39 kA, 65.81 kA

    CB3, 4, 7 ABB, 121PM20, 121 kV, 1200 Amp, 20 KA


    CB20 Power-CB, ABB, K-800M, 0.48 kV, 800 Amp, 42 kA
    This document is confidential and proprietary to ETAP / ETAP Automation and may not be reproduced, published
    or disclosed to others without written authorization of ETAP / ETAP Automation. All Rights Reserved. Page 5 of 6
    ETAP Workshop Notes

    ANSI Short Circuit Example


    CB21 Molded Case, GE, TEML, 0.48kV, 150 Amp, 65 kA
    CB22 Power-CB, ABB, K-800M, 0.48 kV, 800 Amp, 42 kA
    Fuse Gould Shawmut, A4BQ, 0.6 kV, 700 A, 200 kA

    Running Unbalanced SC Calculation

    1. Set up grounding connection


    • Set up layered protection – XFMR delta on HV side and Y grounded on LV side
    • 13.8 kV – 100 amp resistance grounding
    • 4.16 kV – 10 amp resistance grounding
    • 0.48 kV – delta/Y solid-grounded
    • Utility – solid grounded
    • All loads – ungrounded

    2. Run unbalanced calculations using existing configuration and study cases


    • What are the differences between Max, 4, and Min SC calculations?

    3. Check Result
    • Check result on OLV – change display option to show different fault calculation results
    • Check result on crystal report
    • Check effect of grounding connection type and value on zero sequence current

    This document is confidential and proprietary to ETAP / ETAP Automation and may not be reproduced, published
    or disclosed to others without written authorization of ETAP / ETAP Automation. All Rights Reserved. Page 6 of 6

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