N Fault Contribution PDF [PDF]

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ETAP Workshop Notes IEC,IEEE & ETAP Gen Term Flt Calc &Comp

IEC IEEE & ETAP Generator Terminal Fault Calculation and comparison Purpose and Description: The purpose of this exercise is to study the fault current contribution from generator by using IEC-60909 and ANSI/IEEE standard using excel and ETAP. The datasheet of generator is attached at the end of this exercise. Case 1: Calculation of fault current contribution at generator terminal using IEC standard 1.

This exercise involves creating the below shown SLD and entering the corresponding data into the etap. The detailed modelling is shown in subsequent steps.

2. Enter the generator rating and reactance values for Gen1 as shown below.

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Page 1 of 15

ETAP Workshop Notes IEC,IEEE & ETAP Gen Term Flt Calc &Comp

3. Add the dummy transformer. Otherwise etap may show you the below error.

4. Add circuit breaker CB-1 and entered the rating as below.

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

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ETAP Workshop Notes IEC,IEEE & ETAP Gen Term Flt Calc &Comp

Go to SC module, make a new study case as ‘Test_IEC’. 6. Open the study case ‘Test_IEC’, go to the standard page. Choose standard as IEC. Also select user-defined c factor and make it equal to 1 as shown in below image. 5.

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Page 3 of 15

ETAP Workshop Notes IEC,IEEE & ETAP Gen Term Flt Calc &Comp

7. Go to SC module, select bus1, right click on it and make a fault on bus1. 8. Run the 3-phase device duty calculation. 9. Select the Report Manager option (present on the right hand side of the screen in SC Module), select the Summary tab and the PDF option and generate the report. Etap will shows the following results:

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Page 4 of 15

ETAP Workshop Notes IEC,IEEE & ETAP Gen Term Flt Calc &Comp

Excel calculation of short circuit currents by IEC standard: Input require: Generator Data: (The datasheet of generator is attached at the end of this exercise) Un

6.6

kV

Nominal bus

ETAP input required

Urg

6.6

kV

Rating for Gen

ETAP input required

MVA

16.75

Frequency

MVA

ETAP input required

50

Hz

ETAP input required

IrG

1.465

kA

Evaluated in ETAP

pf

0.8

Exciter Type cylindrical round rotor Xd Xd'' X2 Ta

ETAP input required

160

series 2

%

ETAP input required

For steady state short circuit current calculation

Ra

124 10 14.8 0.169

% % % sec

0.2788

%

ETAP input required ETAP input required ETAP input required ETAP input required ETAP input required from vendor data OR Derived From Ta of generator, where 2.pi.f.Ta = X2/Ra

A. Calculation of Ik" including correction factor for Xd" C

1

User defined

Cmax

1.1

KG

1.03774

ZGk

0.10381

pu

ZGk=KG.ZG = KGxsqrt(Ra^2+Xd"^2) as perIEC 60909-2001 eqn. no. 17 of page 61

ZGk

0.26998

Ohm

Where, ZGk in ohm = ZGK pu *Zbase'

As per Table-1(Voltage factor c) of IEC 60909-0-2001 page No.41 KG=( Un/Urg)*(Cmax/(1+Xd"pu*sin(phi)) as perIEC 60909-2001 eqn. no. 18 of page 61

& Z base= kV^2 / MVA= 2.6006 ohm Ik''=

14.115

kA rms

Ik" =C.UN/Sqrt(3)/ZGk as per eqn. no.29 of page no.83 of IEC 60909-0 2001

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

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ETAP Workshop Notes IEC,IEEE & ETAP Gen Term Flt Calc &Comp

B. Calculation of peak SC Ip Rgf Rgf/Xd'' = K=

Ip=

0.07 * Xd''

This value is set inside ETAP software (no user can change this) as per page 63 of IEC 60909-0 2001

0.07

For