SIST-TP CLC/TR 60034-16-2:2005

SLOVENSKI STANDARD
SIST-TP CLC/TR 60034-16-2:2005
01-junij-2005
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Rotating electrical machines - Part 16-2: Excitation systems for synchronous machines -
Models for power system studies (IEC/TR 60034- 16-2:1991)
Drehende elektrische Maschinen - Teil 16-2: Erregersysteme für Synchronmaschinen -
Modelle für Netzstudien (IEC/TR 60034- 16-2:1991)
Machines électriques tournantes - Partie 16-2: Systèmes d'excitation pour machines
synchrones - Modèles pour les études de réseaux (CEI/TR 60034- 16-2:1991)
Ta slovenski standard je istoveten z: CLC/TR 60034-16-2:2004
ICS:
29.160.10 Sestavni deli rotacijskih Components for rotating
strojev machines
SIST-TP CLC/TR 60034-16-2:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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TECHNICAL REPORT CLC/TR 60034-16-2
RAPPORT TECHNIQUE
TECHNISCHER BERICHT September 2004

ICS 29.160.00


English version


Rotating electrical machines
Part 16-2: Excitation systems for synchronous machines -
Models for power system studies
(IEC/TR 60034-16-2:1991)


Machines électriques tournantes Drehende elektrische Maschinen
Partie 16-2: Systèmes d'excitation Teil 16-2: Erregersysteme
pour machines synchrones - für Synchronmaschinen -
Modèles pour les études de réseaux Modelle für Netzstudien
(CEI/TR 60034-16-2:1991) (IEC/TR 60034-16-2:1991)






This Technical Report was approved by CENELEC on 2004-06-12.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. CLC/TR 60034-16-2:2004 E

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CLC/TR 60034-16-2:2004 - 2 -
Foreword
The text of the Technical Report IEC/TR 60034-16-2:1991, prepared by IEC TC 2, Rotating machinery,
was submitted to the formal vote and was approved by CENELEC as CLC/TR 60034-16-2 on
2004-06-12 without any modification.
__________
Endorsement notice
The text of the Technical Report IEC/TR 60034-16-2:1991 was approved by CENELEC as a Technical
Report without any modification.
__________

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RAPPORT CEI
I
TECHNIQUE EC
34-16-2
TECHNICAL
Première édition
REPORT First edition
1991-02
Machines électriques tournantes
Seizième partie:
Systèmes d'excitation pour machines synchrones
Chapitre 2: Modèles pour les études de réseaux
Rotating electrical machines
Part 16:
Excitation systems for synchronous machines
Chapter 2: Models for power system studies
© CEI 1991 Droits de reproduction réservés — Copyright - all rights reserved
Aucune partie de cette publication ne peut Aire reproduite ni No pa tion may be reproduced or utilized In
rt of this publica
utilisée sous quelque forme que ce soit et par aucun pro- any form or by any means, electronic or mechanical,
n
cédé, électronique ou mécanique, y compris la photocopie et including photocopying and mi crofilm, without permissio
les microfilms, sans l'accord écrit de l'éditeur. in writing from the publisher.
Bureau Central de la Commission Electrotechnique Inte rn Genève, Suisse
ationale 3, rue de Varembé
CODE PRIX "
Commission Electrotechnique Internationale
PRICE CODE v
International Electrotechnical Commission
I Memnyuaportaa 3netirporexfiHVectraa lioMrlccwa
EC
Pour prix, voir catalogue en vigueur
• •
For price, see current catalogue

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34-16-2 ©I EC - 3 -
CONTENTS
Page
FOREWORD 5
PREFACE 5
INTRODUCTION 9
Clause
11
1 Scope
2 Exciter categories - Graphical representation and mathematical models for
13
stability studies
2.1 D.C. exciter 13
15
2.2 A.C. exciter
2.3 Potential source static exciter 21
23
2.4 Compound source static exciter
31
2.5 Mathematical models for the control function
43
3 Nomenclature
43
3.1 Parameters
45
3.2 Variables
47
Appendix A - Per unit system
49
Appendix B - Rectifier regulation characteristic
Appendix C - Saturation function 53
55
Appendix D - Representation of limits
Appendix E - Examples of building computer models for specialized excitation
systems 57

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34-16-2 ©IEC - 5 -
COMMISSION
INTERNATIONAL ELECTROTECHNICAL
ROTATING ELECTRICAL MACHINES
Part 16: Excitation systems for synchronous machines
Chapter 2: Models for power system studies
FOREWORD
The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on
1)
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
2) They have the form of recommendations for international use and they are accepted by the National
Committees in that sense.
3) In order to promote international unification, the IEC expresses the wish that all National Committees
should adopt the text of the IEC recommendation for their national rules in so far as national conditions will
permit. Any divergence between the IEC recommendation and the corresponding national rules should, as
far as possible, be clearly indicated in the latter.
PREFACE
This report has been prepared by IEC Technical Committee No. 2: Rotating machinery.
The text of this repo rt is based on the following documents:
Six Months' Rule Report on Voting
2(00)533 2(00)548
Full information on the voting for the approval of this repo rt can be found in the Voting
Repo rt indicated in the above table.
This report forms Chapter 2 of Part 16 of a series of publications dealing with rotating
machinery, the other parts being:
Part 1: Rating and pe
rformance, issued as IEC 34-1.
Part 2: Methods for determining losses and efficiency of rotating electrical machinery from tests
(excluding machines for traction vehicles), issued as IEC 34-2.

Part 3: Specific requirements for turbine-type synchronous machines, issued as IEC 34-3.

Part 4: Methods for determining synchronous machine quantities from tests, issued as IEC 34-4.
Part 5: Classification of degrees of protection provided by enclosures for rotating machines, issued as
IEC 34-5.
Part 6: Methods of cooling rotating machinery, issued as IEC 34-6.

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34-16-2 © IEC - 7 -
Part 7: Symbols for types of construction and mounting arrangements of rotating electrical machinery,
issued as IEC 34-7.
Part 8: Terminal markings and direction of rotation of rotating machines, issued as IEC 34-8.
Part 9: Noise limits, issued as IEC 34-9.
Part 10: Conventions for description of synchronous machines, issued as IEC 34-10.
Part 11: Built-in thermal protection. Chapter 1: Rules for protection of rotating electrical machines, issued
as IEC 34-11.
Part 11-2: Built-in thermal protection. Chapter 2: Thermal detectors and control units used in thermal protec-
tion systems, issued as IEC 34-11-2.
Part 11-3: Built-in thermal protection. Chapter 3: General rules for thermal protectors used in thermal
protection systems, issued as IEC 34-11-3.
Part 12: Starting performance of single-speed three-phase cage induction motors for voltages up to and
including 660 V, issued as IEC 34-12.
Part 13: Specification for mill auxiliary motors, issued as IEC 34-13.
Part 14: Mechanical vibration of ce rtain machines with shaft heights, 66 mm and higher - Measurement,
evaluation and limits of the vibration severity, issued as IEC 34-14.
Part 15: Impulse voltage withstand levels of rotating a.c. machines with form-wound stator coils, issued
as IEC 34-15.
Part 16-1 Excitation systems for synchronous machines. Chapter 1: Definitions, issued as IEC 34-16-1.

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34-16-2 ©IEC - 9 -
INTRODUCTION
When the behaviour of synchronous machines is to be accurately simulated in power
system stability studies, the excitation systems of these machines should be modelled
adequately. Since expenditure for data acquisition, programming and computation has to
be limited in so far as is permissible, it is necessary to use simplified models that provide
reasonable accuracy. The models should adequately represent the actual excitation
system performance:
- during steady-state conditions prior to occurrence of the fault studied;
during the time interval from application to clearing of the fault;
during the oscillations following fault clearing.
The modelling does not account for frequency deviations. It is assumed that in stability
studies frequency deviations of up to ±5 % from the rated frequency can be neglected as
far as the excitation system is concerned.
The excitation system models should be valid for steady-state conditions, for the natural
oscillation frequency of the synchronous machines, and the frequency range in between.
The frequency range to be covered will typically be from 0 Hz to 3 Hz.
Analysis of out-of-step operation, of sub-synchronous resonance or of shaft torsional
effects is beyond the scope of these models.
The operation of protective functions and field discharge or suppression equipment is also
beyond the scope of these models.
The excitation system modelling guidelines and standard models may also be used for stu-
dies of other dynamic problems regarding synchronous machines. However, the models
should then be checked to determine their suitability for that purpose.
The general functional block diagram in figure 1 indicates the various excitation system
components which have to be considered in power system stability studies. These
components include:
-
voltage control elements;
- limiters;
- power system stabilizer (if used);
- exciter power converter (exciter).
The limiters are not normally represented in power system studies.
The main distinctive feature of an excitation system is the manner in which the excitation
power is supplied and converted.

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34-16-2 © IEC - 11 -
ROTATING ELECTRICAL MACHINES
Part 16: Excitation systems for synchronous machines
Chapter 2: Models for power system studies
Scope
This report recommends modelling guidelines and appropriate models for excitation
systems for use in power system stability studies and includes a nomenclature defining
the parameters and variables used.
Definitions for the terms used are given in IEC 34-16-1.
Limiters
Voltage control
Power system
stabilizer elements
Exciter power
converter
(exciter)
Excitation
power
Synchronous machine
and power system
IEC 003/91
Figure 1 - General functional block diagram of excitation systems
(within the dotted block) for synchronous machines

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34-16-2 ©IEC - 13 -
2 Exciter categories - Graphical representation and mathematical models
for stability studies
2.1 D. C. exciter
Although not frequently used on new machines, d.c. exciters are considered because
many synchronous machines presently in service are equipped with this type of exciter.
Figure 2 shows a graphical representation of the type with one separately excited field
E has been introduced in
winding and figure 3 shows the corresponding model. The term K
the model to account for the characteristic of exciters having self-excitation. Note that
KE = 1 in the case of separately excited exciters.
Synchronous machine
Feedback for stabilizing
of the control (where used)
D.C. exciter with field
winding
Input for excitation control
Figure 2 - D.C. exciter with one separately excited field winding
Uf
1
STE
SE +KE
Uf
IEC 005/91
Figure 3 - Model corresponding to figure 2
Several forms of excitation control are in use:
electro-mechanically operated rheostat;
motor-operated rheostat;

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34-16-2©IEC -15-
- periodically closing and short-circuiting of the shunt field circuit;
- use of additional, separately excited fields for buck and boost action;
use of the terminal voltage of an amplidyne in series with the field winding for boost
and buck action.
Considering the dwindling percentage and importance of units equipped with d.c. exciters,
the simple model of figure 3 should prove adequate for these cases.
2.2 A. C. exciter
A.C. exciters employ an a.c. generator together with a stationary or rotating rectifier to
produce the field current for the synchronous machine. The rectifiers may be uncontrolled
or controlled. In the case of uncontrolled rectifiers, control is effected via one or more field
windings of the a.c. exciter.
It is essential to know the source of supply for the a.c. exciter field current via its control
equipment in order to model the control. The source may be an auxiliary generator or a
potential or compound static source.
Figure 4 shows the graphical representation of an a.c. exciter with an uncontrolled
stationary rectifier. The stationary rectifier is fed from the a.c. generator and delivers d.c.
current to the field winding of the synchronous machine via brushes and slip-rings. The
connection of the rotating field winding of the exciter generator to the excitation control is
also made by slip-rings and brushes.
Synchronous machine
Feedback for stabilizing
of the control (where used)
A.C. exciter
Input for excitation control
Figure 4 - A.C. exciter with an uncontrolled stationary rectifier

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- 17 -
34-16-2 ©IEC
Figure 5 shows the graphical representation of an a.c. exciter with an uncontrolled rotating
rectifier (brushless exciter) and permanent magnet auxiliary exciter for supply of the excita-
tion control equipment. The rectifier rotates on a shaft common to the synchronous
machine and the rotating armature for the a.c. exciter. The output of the rotating rectifier is
connected without slip-rings or brushes directly to the field winding of the synchronous
machine.
Synchronous machine
Rotating rectifier
A.C. exciter
Input for excitation control
Permanent magnet generator
for supply of the excitation
control equipment
IEC 007/91
Figure 5 - A.C. exciter with an uncontrolled rotating rectifier
(brushless exciter)

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34-16-2 ©IEC – 19 –
The a.c. exciter can be modelled as shown in figure 6, accounting for both steady-state
and transient exciter loading effects. (In certain cases an even more detailed model may
be used to take into account the effects of transient loads.)
A simplified model is shown in figure 7. Although it accounts only for steady-state loading
effects by use of the load saturation curve, it may be adequate for most studies. The use
of the simplified model may also be indicated where complete data are not available.
Ur
Ue
1 Uf
••
STE
J
+
SE KE
^ • ^.
Fe - f (If , Ue,XE
ie
1
IEC
008/91
Figure 6 - Detailed model of an a.c. exciter
1 Uf
am-
STE
oJ
1EC 009/91
Figure 7 - Simplified model of an a.c. exciter

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34-16-2 ©IEC – 21 –
2.3
Potential source static exciter
Potential source static exciters use rectifier transformers which can be supplied from an
auxiliary generator mounted on the same shaft as the synchronous machine, from an
auxiliary bus system not dependent on the main generator voltage or from the
synchronous machine terminal voltage. The latter is called a shunt static excitation system
and the voltage variations of this system have to be taken into account for the
performance and the modelling. Figure 8 shows the graphical representation of this
system.
Either a full thyristor bridge, or a hybrid bridge having a complement of one half thyristors
and one half diodes, may be used. Firing angle control is frequently used to limit the value
of negative voltage available, giving absolute different values of U + and Up–. The hybrid
o
bridge configuration does not allow inverting and will have a value f Up equal to zero.
In the most commonly applied equipment, the controlled rectifier bridges will allow only
positive excitation current to flow . If synchronous machine terminal disturbances cause a
negative induced field current to flow, the computer model of figure 9 is no longer valid.
The voltage across the synchronous machine field winding will no longer be determined by
the regulator control command but is determined from other considerations beyond the
scope of this report.
Equipment allowing both positive and negative excitation current flow will be required only
under unusual operating circumstances. The computer model of figure 9 is applicable even
under these conditions for such systems.
Synchronous machine Rectifier transformer
Controlled rectifiers
Alternatives
!EC 010/91
Figure 8 - Potential source static excitation system

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34-16-2 © IEC - 23 -
Model:
Ut
UtN UP+
Uf
Ur 1
No-
1 + s TE
Ut ) Up —
UtN
If
t-
Xp
Symbol:
(tit
Up +
UtN
7-
Ur
Uf
ill■
If Converter
Ut
U—P
UtN !EC 011/91
Figure 9 - Potential source excitation system model and symbol
2.4 Compound source static exciter
Compound source static exciters use rectifier transformers supplied from both current and
voltage sources (synchronous machine quantities). There are a number of design
possibilities. Three commonly used forms will be described.

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34-16-2 ©IEC - 25 -
The first example, figure 10, illustrates the concept of addition of voltages from the two
sources in series on the d.c. side of the rectifiers. The current transformers have a special
magnetic circuit design or use separate reactors as shown in figure 10, the corresponding
model of which is given in figure 11.
Rectifier and
Synchronous machine controlled
rectifiers
Current source
transformers
(EC 012/91
Figure 10 -Compound source static exciter with addition of voltages in series
on the d.c. side
If
(ut)
P+
UU
U^ Uf
+ s TE
Ut
-I
UtN
UBMAX.
= f(If. Ue.XEI

(EC 013/91
Figure 11 - Model corresponding to figure 10
A second example, figure 12, illustrates the concept of addition of currents from the two
sources in parallel on the a.c. side of the rectifiers. The potential source transformers
have a special magnetic circuit design or use separate reactors as shown. Control is
accomplished by diverting a part of the current sum through controlled rectifiers.

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34-16-2©IEC - 27 -
Another design variation (not illustrated) uses separate internal machine windings for
...