ETAP Knowledge Base
Component Models for Harmonic Analysis
Description: Component models for Harmonic analysis
Category:
Harmonic Load Flow, Harmonic Frequency Scan
Type:
Modeling
Keywords:
Harmonic Analysis, Component Model
The following table shows the equivalent impedance of system components as a function of
harmonic order h in Harmonic Load Flow Analysis. If a component has a harmonic source
selected the impedance is not considered. Harmonic Frequency Scan uses the positive
sequence network with h = f /f1, where f is scan frequency and f1 is the fundamental frequency.
Component



Synchronous
Motor
Synchronous
Generator
Utility/Grid
WTG

Induction Machine


Impedance Branch
+/‐ Sequence Harmonics
Zero Sequence Harmonics
R2  j  h  X 2
R0  j  h  X 0
R  jh X 2
R0  j  h  X 0
R1  j  h  X 1
R0  j  h  X 0
j  h  Y1
j  h  Y1
This document is confidential and proprietary to Operation Technology, Inc. and may not be reproduced, published or disclosed to
others without the written authorization of Operation Technology, Inc., 17 Goodyear, Suite 100, Irvine, CA 92618, USA. © 2010 by
Operation Technology, Inc. All Rights Reserved.
© Operation Technology, Inc.
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ETAP Knowledge Base
Component Models for Harmonic Analysis
Component
+/‐ Sequence Harmonics
Zero Sequence Harmonics
1
1
1

R eq j  h  X eq


Static Load
Lumped Load
(all load types)
MOV
V2
P
V2

Q
Req 
X eq
Same as +/‐ Seq.
(P and Q are the fundamental real and
reactive power into the load. V is the
fundamental load terminal voltage.)

Transformer
Reactor
R1  (0.8  0.2  h 2 )  j  h  X 1
R0  (0.8  0.2  h 2 )  j  h  X 0
Pos. Sequence
R1  [1  0.2  log(h)]  j 


Transmission
Line (Short)
Cable (Short)
h  X1
1  0.1  log(h)
j  h  Y1
R0  [1  0.2  log(h)]  j 
Neg. Sequence
R 2  [1  0.2  log(h)]  j 
h X0
1  0.1  log(h)
h X 2
1  0.1  log(h)
j  h Y 2
This document is confidential and proprietary to Operation Technology, Inc. and may not be reproduced, published or disclosed to
others without the written authorization of Operation Technology, Inc., 17 Goodyear, Suite 100, Irvine, CA 92618, USA. © 2010 by
Operation Technology, Inc. All Rights Reserved.
© Operation Technology, Inc.
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Component Models for Harmonic Analysis
Component
+/‐ Sequence Harmonics
Zero Sequence Harmonics
Pos. Sequence
z  R1  j  h  X 1
y  j  h  Y1
z  R0  j  h  X 0
y  j  h Y 0
Neg. Sequence


Transmission
Line (Long)
Cable (Long)
z  R2  j  h  X 2
y  j  h Y 2
Z line / cab 

z y

Yline / cab

2
z
sinh
y

z y
UPS
VFD
Charger
Inverter
PV Array
HVDC Link
SVC
See Remark 1
See Remark 1
Capacitor
j  Xc
h
V2
Xc 
Q
Same as +/‐ Seq.


This document is confidential and proprietary to Operation Technology, Inc. and may not be reproduced, published or disclosed to
others without the written authorization of Operation Technology, Inc., 17 Goodyear, Suite 100, Irvine, CA 92618, USA. © 2010 by
Operation Technology, Inc. All Rights Reserved.
© Operation Technology, Inc.
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
y
1

tanh
z y
z
2

y
1

tanh
z y
z
2

Yline / cab

2







z
sinh
y
Z line / cab 
ETAPKB
ETAP Knowledge Base
Component Models for Harmonic Analysis
Component

+/‐ Sequence Harmonics
Zero Sequence Harmonics
j  Xc
h
Capacitors:
‐
Inductors:
j  h  Xl
Same as +/‐ Seq.
Harmonic Filter
Resistors:
R
(The equivalent impedance depends on
the topology of the filter selection)
Remarks:
1. In ETAP 11, all power electronic type devices are to be modeled as a harmonic source
or else they will be seen as infinite impedance.
2. Numerals 1, 2, and 3 denote positive, negative, and zero sequence respectively
This document is confidential and proprietary to Operation Technology, Inc. and may not be reproduced, published or disclosed to
others without the written authorization of Operation Technology, Inc., 17 Goodyear, Suite 100, Irvine, CA 92618, USA. © 2010 by
Operation Technology, Inc. All Rights Reserved.
© Operation Technology, Inc.
Page 4 of 4
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