EN IEC 60034-3:2020
(Main)Rotating electrical machines - Part 3: Specific requirements for synchronous generators driven by steam turbines or combustion gas turbines and for synchronous compensators
Rotating electrical machines - Part 3: Specific requirements for synchronous generators driven by steam turbines or combustion gas turbines and for synchronous compensators
IEC 60034-3:2020 applies to large three-phase synchronous generators, having rated outputs of 10 MVA and above driven by steam turbines or combustion gas turbines. Also included are synchronous Mvar compensators of the same output range connected to a grid for the purpose of exchanging reactive power. This document supplements basic requirements for rotating machines given in IEC 60034-1. This seventh edition cancels and replaces the sixth edition published in 2007. This edition includes the following significant technical changes with respect to the previous edition: - title modified; - scope extended to synchronous compensators; - rotor overcurrent requirements added; - impact of stator harmonics on rotor unbalanced load capability introduced; - synchronisation requirements added; - adjustments of temperatures or temperature rise revised for gas turbine applications; - requirements for auxiliaries updated.
Drehende elektrische Maschinen - Teil 3: Besondere Anforderungen an Synchrongeneratoren, angetrieben durch Dampfturbinen oder Gasturbinen, und an synchrone Phasenschieber
Machines électriques tournantes - Partie 3: Exigences spécifiques pour les alternateurs synchrones entraînés par des turbines à vapeur ou par des turbines à gaz et pour les compensateurs synchrones
l'IEC 60034-3:2020 s'applique aux alternateurs triphasés synchrones de grande taille, de puissance assignée supérieure ou égale à 10 MVA, entraînés par des turbines à vapeur ou par des turbines à gaz. Elle inclut également les compensateurs Mvar synchrones de même puissance connectés à un réseau, destinés à échanger de la puissance réactive. Le présent document constitue un complément aux exigences de base pour les machines tournantes données dans l'IEC 60034-1. Cette septième édition annule et remplace la sixième édition parue en 2007. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - modification du titre; - extension du domaine d'application aux compensateurs synchrones; - ajout d'exigences concernant la surintensité du rotor; - introduction de l'impact des harmoniques statoriques sur la performance de la charge déséquilibrée du rotor; - ajout d'exigences concernant la synchronisation; - révision des ajustements des températures ou des échauffements pour les installations de type turbines à gaz; - mise à jour des exigences concernant les auxiliaires.
Električni rotacijski stroji - 3. del: Posebne zahteve za sinhronske generatorje, ki jih poganjajo parne ali plinske turbine, in za sinhronske kompenzatorje (IEC 60034-3:2020)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2020
Nadomešča:
SIST EN 60034-3:2008
Električni rotacijski stroji - 3. del: Posebne zahteve za sinhronske generatorje, ki
jih poganjajo parne ali plinske turbine, in za sinhronske kompenzatorje (IEC 60034-
3:2020)
Rotating electrical machines - Part 3: Specific requirements for synchronous generators
driven by steam turbines or combustion gas turbines and for synchronous compensators
(IEC 60034-3:2020)
Drehende elektrische Maschinen - Teil 3: Besondere Anforderungen an
Synchrongeneratoren, angetrieben durch Dampfturbinen oder Gasturbinen, und an
synchrone Phasenschieber (IEC 60034-3:2020)
Machines électriques tournantes - Partie 3: Exigences spécifiques pour les alternateurs
synchrones entraînés par des turbines à vapeur ou par des turbines à gaz et pour les
compensateurs synchrones (IEC 60034-3:2020)
Ta slovenski standard je istoveten z: EN IEC 60034-3:2020
ICS:
27.040 Plinske in parne turbine. Gas and steam turbines.
Parni stroji Steam engines
29.160.20 Generatorji Generators
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 60034-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2020
ICS 29.160.01 Supersedes EN 60034-3:2008 and all of its amendments
and corrigenda (if any)
English Version
Rotating electrical machines - Part 3: Specific requirements for
synchronous generators driven by steam turbines or combustion
gas turbines and for synchronous compensators
(IEC 60034-3:2020)
Machines électriques tournantes - Partie 3: Exigences Drehende elektrische Maschinen - Teil 3: Besondere
spécifiques pour les alternateurs synchrones entraînés par Anforderungen an Synchrongeneratoren, angetrieben durch
des turbines à vapeur ou par des turbines à gaz et pour les Dampfturbinen oder Gasturbinen, und an synchrone
compensateurs synchrones Phasenschieber
(IEC 60034-3:2020) (IEC 60034-3:2020)
This European Standard was approved by CENELEC on 2020-06-30. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60034-3:2020 E
European foreword
The text of document 2/1987/FDIS, future edition 7 of IEC 60034-3, prepared by IEC/TC 2 "Rotating
machinery" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2021-03-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2023-06-30
document have to be withdrawn
This document supersedes EN 60034-3:2008 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 60034-3:2020 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 60079-0 NOTE Harmonized as EN IEC 60079-0
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60034-1 2017 Rotating electrical machines - Part 1: Rating - -
and performance
IEC 60034-4-1 - Rotating electrical machines - Part 4-1: EN IEC 60034-4-1 -
Methods for determining electrically excited
synchronous machine quantities from tests
IEC 60045-1 - Steam turbines - Part 1: Specifications EN IEC 60045-1 -
IEC 60079 series Explosive atmospheres EN IEC 60079 series
IEC 60085 - Electrical insulation - Thermal evaluation and EN 60085 -
designation
IEC 60034-3 ®
Edition 7.0 2020-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Rotating electrical machines –
Part 3: Specific requirements for synchronous generators driven by steam
turbines or combustion gas turbines and for synchronous compensators
Machines électriques tournantes –
Partie 3: Exigences spécifiques pour les alternateurs synchrones entraînés
par des turbines à vapeur ou par des turbines à gaz et pour les compensateurs
synchrones
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.160.01 ISBN 978-2-8322-8084-3
– 2 – IEC 60034-3:2020 © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 General . 8
4.1 General rules . 8
4.2 Rated conditions . 9
4.2.1 Generators . 9
4.2.2 Compensators . 9
4.3 Rated voltage . 9
4.4 Power factor . 9
4.5 Rated speed . 10
4.6 Ranges of voltage and frequency . 10
4.7 Direction of rotation . 11
4.8 Stator winding, output voltage . 11
4.9 Winding insulation . 11
4.9.1 Insulation systems, thermal class . 11
4.9.2 Withstand voltage tests. 11
4.10 Insulation against shaft current . 12
4.11 Overspeed test . 12
4.12 Critical speeds . 12
4.13 P-Q capability diagram . 12
4.14 Overcurrent requirements . 14
4.14.1 General . 14
4.14.2 Stator current . 14
4.14.3 Rotor field current . 14
4.15 Unbalanced currents and current harmonics capability . 15
4.15.1 Negative sequence current . 15
4.15.2 Current harmonics . 15
4.16 Sudden short circuit . 16
4.17 Synchronisation . 16
4.18 Short circuit ratio (SCR) . 17
4.19 Direct axis transient and subtransient reactances . 17
4.20 Tolerances on short circuit ratio and direct axis transient and subtransient
reactances . 17
4.21 Mechanical conditions for rotors . 17
4.21.1 Number of starts . 17
4.21.2 Turning gear operation . 18
4.22 Coolers . 18
5 Air-cooled generators or compensators . 18
5.1 General . 18
5.2 Cooling system . 18
5.3 Temperature of primary coolant . 19
5.3.1 General . 19
5.3.2 Temperature detectors . 19
6 Hydrogen-cooled or liquid-cooled generators or compensators . 19
IEC 60034-3:2020 © IEC 2020 – 3 –
6.1 General . 19
6.2 Hydrogen pressure and purity in the casing . 19
6.3 Machine housing and cover plates . 20
6.4 Stator winding terminals . 20
6.5 Temperature of primary coolants, temperatures and temperature rises . 20
6.6 Temperature detectors . 20
6.7 Auxiliary systems . 21
7 Generators for combustion gas turbines or combined cycle applications . 21
7.1 General . 21
7.2 Service conditions . 21
7.2.1 General . 21
7.2.2 Primary coolant temperature . 22
7.2.3 Number of starts . 22
7.2.4 Application of load . 22
7.3 Rated output . 22
7.4 Capabilities . 22
7.4.1 General . 22
7.4.2 Base capability . 22
7.4.3 Temperature rise and temperatures at base capability . 24
7.4.4 Peak capability . 24
7.5 Rating plate . 25
7.6 Temperature tests . 25
Annex A (normative) Precautions to be taken when using hydrogen- cooled
synchronous generators or compensators . 26
A.1 General . 26
A.2 Hydrogen purity . 26
A.3 Normal operating conditions. 26
A.4 Protective measures for sliprings and coupled exciters . 26
A.5 Auxiliary equipment . 27
A.5.1 General . 27
A.5.2 Degassing tanks . 27
A.5.3 Gas dryer . 27
A.5.4 Instrumentation, control devices . 27
A.5.5 Electrical connections . 27
A.5.6 Containment of hydrogen . 28
A.5.7 Accumulation of hydrogen-air mixture . 29
A.5.8 Vent pipes . 29
A.5.9 Adjacent area . 29
A.6 Operation of the generator and its auxiliary equipment. 29
A.6.1 Sources of ignition . 29
A.6.2 Hydrogen-air mixture . 29
A.6.3 Air or hydrogen displacement . 29
A.6.4 Seal oil supply and hydrogen pressure . 30
A.6.5 Gas tightness . 30
A.6.6 Water system . 31
A.7 Guidance for adequate ventilation . 31
Bibliography . 33
Figure 1 – Operation over ranges of voltage and frequency . 10
– 4 – IEC 60034-3:2020 © IEC 2020
Figure 2 – Typical P-Q capability diagram of a generator . 13
Figure 3 – Typical generator capability curves . 23
Figure A.1 – Example of a large hydrogen supply unit feeding one or more generators
(simplified diagram) . 32
IEC 60034-3:2020 © IEC 2020 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –
Part 3: Specific requirements for synchronous generators
driven by steam turbines or combustion gas turbines
and for synchronous compensators
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60034-3 has been prepared by IEC technical committee 2: Rotating
machinery.
This seventh edition cancels and replaces the sixth edition published in 2007. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) title modified;
b) scope extended to synchronous compensators;
c) rotor overcurrent requirements added;
d) impact of stator harmonics on rotor unbalanced load capability introduced;
e) synchronisation requirements added;
– 6 – IEC 60034-3:2020 © IEC 2020
f) adjustments of temperatures or temperature rise revised for gas turbine applications;
g) requirements for auxiliaries updated.
The text of this standard is based on the following documents:
FDIS Report on voting
2/1987/FDIS 2/1993/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 60034 series, published under the general title Rotating electrical
machines, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IEC 60034-3:2020 © IEC 2020 – 7 –
ROTATING ELECTRICAL MACHINES –
Part 3: Specific requirements for synchronous generators
driven by steam turbines or combustion gas turbines
and for synchronous compensators
1 Scope
This part of IEC 60034 applies to large three-phase synchronous generators, having rated
outputs of 10 MVA and above driven by steam turbines or combustion gas turbines. Also
included are synchronous Mvar compensators of the same output range connected to a grid for
the purpose of exchanging reactive power.
This document supplements basic requirements for rotating machines given in IEC 60034-1.
Common requirements are specified together with specific requirements for air, hydrogen or
liquid cooled synchronous generators or compensators.
This document also gives the precautions to be taken when using hydrogen cooled generators
including:
• rotating exciters driven by synchronous generators;
• auxiliary equipment needed for operating the generators;
• parts of the building where hydrogen might accumulate.
These requirements also apply to a synchronous generator driven by both a steam turbine and
a combustion gas turbine as part of a single shaft combined cycle unit.
These requirements do not apply to synchronous generators driven by water (hydraulic)
turbines or wind turbines.
NOTE The precautions taken when using hydrogen are valid for all cases where hydrogen is used as a coolant.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60034-1:2017, Rotating electrical machines – Part 1: Rating and performance
IEC 60034-4-1, Rotating electrical machines – Part 4-1: Methods for determining electrically
excited synchronous machine quantities from tests
IEC 60045-1, Steam turbines – Part 1: Specifications
IEC 60079 (all parts), Explosive atmospheres
IEC 60085, Electrical insulation – Thermal evaluation and designation
– 8 – IEC 60034-3:2020 © IEC 2020
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60034-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
grid
public electrical network or local (e.g. industrial) network, which is connected to the generator
or compensator either directly or through a transformer
3.2
synchronous generator
large synchronous machine driven by steam or gas turbines which converts mechanical energy
into electrical energy and supplies it to an electrical grid
Note 1 to entry: Generators can also provide reactive power to the grid. The driving unit itself or additional
equipment is used to start up the generating unit.
3.3
synchronous compensator
large synchronous machine electrically coupled to the grid but not exchanging mechanical
energy through the shaft during steady state operation
Note 1 to entry: Reactive power is supplied to the grid or imported to the compensator by means of adjusting the
field current.
Note 2 to entry: The losses are covered by the grid. A compensator needs a start-up device, which accelerates the
unit to operating speed or can be started asynchronously if design is appropriate.
Note 3 to entry: Synchronous compensators are commonly named synchronous condensers.
3.4
mechanical start
change in speed from zero or turning gear speed to rated speed
3.5
turning gear operation
rotation at low speed to avoid undesirable bending of turbine- and/or generator/compensator-
rotors due to uneven circumferential temperature distribution
4 General
4.1 General rules
Turbine driven synchronous generators and synchronous compensators shall fulfil the basic
requirements for rotating machines specified in IEC 60034-1 unless otherwise specified in this
document.
Wherever there is reference to an agreement in this document, it shall be understood as an
agreement between manufacturer and purchaser.
IEC 60034-3:2020 © IEC 2020 – 9 –
4.2 Rated conditions
4.2.1 Generators
The rated conditions of a generator are given by the rated values of:
• the apparent power;
• frequency;
• voltage;
• power factor;
• primary coolant temperature (40°C unless otherwise agreed upon);
• field current and field voltage (see also 4.2.2);
and where applicable:
• site altitude;
• hydrogen pressure with indication whether the figure is to be interpreted as absolute or
gauge pressure;
• range of hydrogen purity, see IEC 60034-1.
4.2.2 Compensators
The rated conditions of a compensator are basically the same as those of a generator but with
different definitions of apparent power and power factor.
• The rated apparent power consists mainly of the maximum continuous reactive output at
rated voltage when the machine is overexcited, and of a small amount of active power
delivered to the compensator.
• The rated power factor is close to zero, reflecting mainly the maximum reactive power and
the losses compensated by the grid.
For compensators, the range of reactive power shall be agreed upon.
NOTE During operation, the field current of a generator or compensator is adjusted depending on the demand of
reactive power. Generator/compensator rated field current and field voltage are those values needed to operate the
generator/compensator at rated conditions. Generator/compensator modelling studies can require base values for
field current and field voltage other than rated.
4.3 Rated voltage
The rated voltage shall be agreed upon.
4.4 Power factor
The power factor of a generator shall be agreed upon. Standardised rated power factors at the
generator terminals are 0,8, 0,85 and 0,9 overexcited.
It is recommended that the generator be capable of providing a power factor of 0,95
underexcited at rated active power output.
NOTE The lower the rated power factor the larger the generator will be.
The rated power factor should reflect the demand on reactive power overexcited at rated active
power output including some margin.
The power factor of a synchronous compensator deviates from zero only by an amount, which
depends on the losses compensated by the grid.
– 10 – IEC 60034-3:2020 © IEC 2020
4.5 Rated speed
Synchronous generators or compensators are typically connected to a grid with a fundamental
operating frequency of 50 Hz or 60 Hz.
The rated speed is:
–1
3 000/p min for 50 Hz generators or compensators;
–1
3 600/p min for 60 Hz generators or compensators;
where p is the number of pole pairs.
4.6 Ranges of voltage and frequency
Synchronous generators and compensators shall be capable of continuous rated output at the
rated power factor over the ranges of ±5 % in voltage and ±2 % in frequency, as defined by the
shaded area of Figure 1.
The temperature rise limits in Tables 8 and 9 of IEC 60034-1:2017, or the temperature limits in
Table 13 of IEC 60034-1:2017 shall apply at the rated voltage and frequency.
Continuous operation at rated output at certain parts of the boundary of the shaded area may
cause additional temperature rise of up to approximately 10 K.
Generators or compensators will also carry output at rated power factor within the ranges of
±5 % in voltage and -5 % to +3 % in frequency, as defined by the outer boundary of Figure 1,
but temperature rises will be further increased. Therefore, operation outside the shaded area
should be limited in extent, duration and frequency of occurrence in order to minimize the
reduction of lifetime due to thermal effects. The output should be reduced or other corrective
measures taken as soon as practicable.
Potentially required operation outside the dashed borderline of Figure 1 shall be the subject of
an agreement.
Figure 1 – Operation over ranges of voltage and frequency
IEC 60034-3:2020 © IEC 2020 – 11 –
NOTE Overvoltage together with low frequency, or low voltage with over-frequency, are considered to be unlikely
operating conditions. The former condition most likely increases the temperature rise of the field winding. Figure 1
shows operation in these quadrants restricted to conditions that will cause the generator or compensator and its
transformer to be over- or under-fluxed by approximately 5 %. Margins of excitation and of stability will be reduced
under some of the operating conditions shown. With the operating frequency deviating from the rated frequency,
effects outside the generator or compensator can become important and will be considered. For example: the turbine
manufacturer will specify permissible ranges of frequency and corresponding operating periods. Also, a certain range
of permissible operating voltages and frequencies can apply to auxiliary equipment.
4.7 Direction of rotation
The direction of rotation shall be shown on the machine or on its rating plate, and the time-
phase sequence of the stator voltage shall then be indicated by marking the terminals in the
sequence in which their voltages reach maximum, for example, U1, V1, W1.
NOTE Terminal markings may not be consistent with IEC 60034-8.
For generators having one driven end, this shall be the reference end for the direction of
rotation.
For generators driven on both ends, the end of the more powerful drive shall be the reference
end. In case of comparable drive power on either end, the end opposite to the excitation
terminals shall be the reference end for the direction of rotation.
The reference end of synchronous compensators shall be the end opposite to the excitation
terminals.
The sense of rotation (clockwise or counter-clockwise) shall be defined when facing the rotor
from the reference side.
The phase sequence of the generator or compensator shall coincide with the phase sequence
of the grid to which the generator or compensator is to be connected.
4.8 Stator winding, output voltage
Unless otherwise agreed upon, the stator winding shall be arranged in star configuration. All
phase ends shall be accessible from outside of the casing. The arrangement of the electrical
terminals shall be agreed upon.
Output voltage is defined as the line to line voltage of the stator winding.
4.9 Winding insulation
4.9.1 Insulation systems, thermal class
The stator winding as well as the field winding shall be insulated with appropriate insulating
systems. An insulation system includes the necessary combinations of insulating materials
around the electrical conductors.
Insulation systems used for the windings of a generator or compensator shall be classified
according to IEC 60085. Thermal class 130 (B) or higher shall be applied.
NOTE The term “winding” includes the coils and all electrical connections between coils and terminals.
4.9.2 Withstand voltage tests
Withstand voltage tests shall be in accordance with IEC 60034-1:2017, 9.2.
– 12 – IEC 60034-3:2020 © IEC 2020
4.10 Insulation against shaft current
Suitable precautions shall be taken to prevent harmful flow of shaft current and to earth the
rotor shaft adequately. A turbine-generator shaft shall be earthed at a shaft position close to
the reference end of the generator. Shaft voltage spikes caused by static excitation with
controlled rectifiers shall be kept down by suitable means to non-critical values. These spikes
can cause damage, for example to the bearing Babbitt, by breaking through the bearing oil film.
Requirements for bearing insulation resistance to be measured during operation of the
generator or compensator shall be agreed upon at the time of purchase.
4.11 Overspeed test
Rotors, i.e. main shaft and if applicable slip ring shaft or exciter shaft, shall each be tested
completely assembled at 1,2 times rated speed for 2 min.
If rotor fan blades are not assembled to avoid larger windage loss at overspeed test, this can
be acceptable when the mechanical strength is assured by traceability of the material which
would be proven by mill test report and non-destructive test report for design requirements.
The purpose of the rotor over-speed test is verifying the mechanical integrity of the rotor. This
test is not intended to indicate the in-service operating capability of the machine. The in-service
over-speed withstand capability of the generator/compensator and the frequency with which
such an over-speed may be applied depends upon the design of the generator or compensator.
It is necessary to consider carefully any in-service over-speed conditions which could result
from sudden disconnection of full load for example. Any particular requirements shall be agreed
upon.
4.12 Critical speeds
Critical speeds shall not cause unsatisfactory operation of the combined generator-/turbine-
shaft train within the speed-/frequency-range corresponding to IEC 60045-1 or agreed upon
otherwise. This also applies to compensator rotors.
If generator and turbine are purchased from different manufacturers, there shall be an
agreement on which party is responsible for achieving the desired performance of the combined
turbine/generator shaft line including exchange of turbine and generator shaft data.
4.13 P-Q capability diagram
For generators, the manufacturer shall supply a P-Q capability diagram indicating the limits of
operation. The P-Q diagram shall be drawn for operation at rated conditions. A typical P-Q
diagram is shown in Figure 2; its boundaries are set by the following limitations:
• curve A represents operation with constant rated field current and therefore with
approximately constant temperature rise of the field winding;
• curve B represents constant rated stator current and consequently approximately constant
temperature rise of the stator winding;
• curve C represents limits due to the temperatures of the core end parts. In many cases this
line is also shown as constrained by stability considerations, determination of which requires
knowledge of the power system to which the machine will be connected. Such power system
data is frequently unavailable or insufficient when a “synchronous machine only P-Q
diagram” is created. Hence, it is common for line C on the P-Q diagram, for a machine alone,
to be drawn showing any absolute limits required to protect core end parts and showing
further stability factor constraints for illustration purposes only.
Additional diagrams may be provided for operation at agreed conditions, for instance at reduced
cooling or, where applicable, at hydrogen pressures other than rated.
IEC 60034-3:2020 © IEC 2020 – 13 –
For synchronous compensators no P-Q capability applies.
If a particular generator or motor with existing P-Q capability is used as a synchronous
compensator, the available output range of reactive power can be understood as the line
between the intersection of the Q-axis and curve A and the intersection of the Q-axis and curve
C of the P-Q diagram. The losses compensated by the grid would cause a slight shift of the
operating point towards negative values on the P -axis.
The generator should be operated within the boundaries of the diagram at the applicable cooling
conditions Operation outside these boundaries will shorten the life of the generator.
Key
A limited by field winding temperature P per unit kW
B limited by stator winding temperature Q per unit kvar overexcited
C limited by the temperatures of the core-end parts or by steady Q' per unit kvar underexcited
state stability, including margin to theoretical limits
D rated output per unit kVA
Figure 2 – Typical P-Q capability diagram of a generator
NOTE 1 Figure 2 can contain other operational limits such as maximum turbine limits or minimum excitation limits.
NOTE 2 Figure 2 can be supplemented with isolines of constant efficiency.
NOTE 3 It is understood that Figure 2 gives the permissible load points with all limiters of the automated voltage
regulator (AVR) engaged.
NOTE 4 Increases in renewable energy generation and the consequent frequent changes of load points of
synchronous machines can impact the lifetime of the machine.
– 14 – IEC 60034-3:2020 © IEC 2020
4.14 Overcurrent requirements
4.14.1 General
Subclauses 4.14.2 and 4.14.3 are primarily intended to ensure that the generator can provide
sufficient current without damage during short circuit conditions. It is not a requirement that
rated voltage be maintained during this condition.
It is recognized that stator temperatures will exceed rated load values under these conditions,
and therefore the generator or compensator design is based upon the assumption that the
number of operations at these limiting conditions will not exceed two per year.
It is not intended by this document to test this severe condition for compliance.
4.14.2 Stator current
Generators or compensators with rated outputs up to 1 200 MVA shall be capable of carrying,
without damage, a stator current of 1,5 per unit (p.u.) for 30 s, starting from stabilized
temperatures at rated conditions, defining certain additional heat.
Other combinations of stator overcurrent and time, which add the same additional heat to the
heat caused by rated stator current, shall be permissible.
Thus, for generators/compensators up to 1 200 MVA,
(i – 1)t = 37,5 s
where
i is the stator current per unit (Ι/Ι );
N
Ι is the stator current;
I is the rated stator current;
N
t is its duration in seconds.
This formula shall apply for values of t between 10 s and 120 s.
For ratings greater than 1 200 MVA, agreement shall be reached on a time duration less than
30 s, decreasing as the rating increases, to a minimum of 15 s, the current remaining at 1,5 per
unit for all ratings.
4.14.3 Rotor field current
The rotor winding shall be capable of carrying a rotor current of 1,25 per unit (p.u.) for 60 s,
starting from stabilized temperatures at rated conditions, defining certain additional heat.
Other combinations of rotor overcurrent and time shall be permissible, which add the same
additional heat to the heat caused by rated field current.
(i – 1)t = 33,75 s
f
where
i is the rotor field current per unit (Ι /Ι );
f f fN
Ι is the rotor field current;
f
Ι is the rated rotor field current;
fN
t is its duration in seconds.
IEC 60034-3:2020 © IEC 2020 – 15 –
This formula shall apply for values of t between 10 s and 120 s.
4.15 Unbalanced currents and current harmonics capability
4.15.1 Negative sequence current
IEC60034-1:2017, Table 2, defines limitations for the unbalanced load of synchronous
machines:
• continuous negative phase sequence currents Ι /Ι ;
2 N
• short-time capability (Ι /Ι ) t
2 N
assuming phase currents having fundamental frequency only and with Ι as the negative
sequence current based on these fundamentals.
4.15.2 Current harmonics
If harmonics of the fundamental frequency with significant levels are present in the stator phase
currents, additional currents will be induced in the damper circuit, for example on the rotor
surface, in the rotor damper w
...
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