SIST-TS CLC/TS 60034-27:2011

SLOVENSKI STANDARD
SIST-TS CLC/TS 60034-27:2011
01-april-2011
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Rotating electrical machines - Part 27: Off-line partial discharge measurements on the
stator winding insulation of rotating electrical machines (IEC/TS 60034-27:2006)
Drehende elektrische Maschinen - Teil 27: Off-line-Teilentladungsmessungen an der
Statorwicklungsisolation drehender Maschinen (IEC/TS 60034-27:2006)
Machines électriques tournantes - Partie 27: Mesures à l'arrêt des décharges partielles
effectuées sur le système d'isolation des enroulements statoriques des machines
électriques tournantes (CEI/TS 60034-27:2006)
Ta slovenski standard je istoveten z: CLC/TS 60034-27:2011
ICS:
29.160.01 Rotacijski stroji na splošno Rotating machinery in
general
SIST-TS CLC/TS 60034-27:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CLC/TS 60034-27:2011

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SIST-TS CLC/TS 60034-27:2011

TECHNICAL SPECIFICATION
CLC/TS 60034-27

SPÉCIFICATION TECHNIQUE
February 2011
TECHNISCHE SPEZIFIKATION

ICS 29.160


English version


Rotating electrical machines -
Part 27: Off-line partial discharge measurements on the stator winding
insulation of rotating electrical machines
(IEC/TS 60034-27:2006)


Machines électriques tournantes -  Drehende elektrische Maschinen -
Partie 27: Mesures à l'arrêt des décharges Teil 27: Off-line-Teilentladungsmessungen
partielles effectuées sur le système an der Statorwicklungsisolation drehender
d'isolation des enroulements statoriques Maschinen
des machines électriques tournantes (IEC/TS 60034-27:2006)
(CEI/TS 60034-27:2006)





This Technical Specification was approved by CENELEC on 2011-01-25.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to
make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting
national standards in force.

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, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.



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

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 60034-27:2011 E

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SIST-TS CLC/TS 60034-27:2011
CLC/TS 60034-27:2011 - 2 -
Foreword
The text of the Technical Specification IEC/TS 60034-27:2007, prepared by IEC TC 2, Rotating
machinery, was submitted to the formal vote and was approved by CENELEC as CLC/TS 60034-27 on
2011-01-25.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following date was fixed:
– latest date by which the existence of the CLC/TS
has to be announced at national level (doa) 2011-07-25
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the Technical Specification IEC/TS 60034-27:2006 was approved by CENELEC as a
Technical Specification without any modification.

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SIST-TS CLC/TS 60034-27:2011
- 3 - CLC/TS 60034-27:2011
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year

IEC 60060-1 - High-voltage test techniques - EN 60060-1 -
Part 1: General definitions and test
requirements


IEC 60060-2 - High-voltage test techniques - EN 60060-2 -
Part 2: Measuring systems


IEC 60270 2000 High-voltage test techniques - Partial EN 60270 2001
discharge measurements

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SIST-TS CLC/TS 60034-27:2011

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SIST-TS CLC/TS 60034-27:2011
SPÉCIFICATION CEI
TECHNIQUE
IEC



TS 60034-27
TECHNICAL


Première édition
SPECIFICATION

First edition

2006-12


Machines électriques tournantes –
Partie 27:
Mesures à l’arrêt des décharges partielles
effectuées sur le système d’isolation des
enroulements statoriques des machines
électriques tournantes

Rotating electrical machines –
Part 27:
Off-line partial discharge measurements
on the stator winding insulation of rotating
electrical machines
© IEC 2006 Droits de reproduction réservés ⎯ Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
XA
PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 3 –
CONTENTS
FOREWORD.7
INTRODUCTION.11

1 Scope.15
2 Normative references .15
3 Terms and definitions .15
4 Nature of PD in rotating machines .19
4.1 Basics of PD .19
4.2 Types of PD in rotating machines .21
4.3 Pulse propagation in windings .23
5 Measuring techniques and instruments.25
5.1 General .25
5.2 Influence of frequency response of measurement system.25
5.3 Effects of PD coupling units.27
5.4 Wide-band and narrow band measuring systems.29
6 Visualization of measurements .33
6.1 General .33
6.2 Minimum scope of PD data presentation.33
6.3 Additional means of PD data representation .35
7 Test circuits.39
7.1 General .39
7.2 Individual winding components .39
7.3 Complete winding.43
8 Normalization of measurements .47
8.1 General .47
8.2 Individual winding components .49
8.3 Complete windings .49
9 Test procedures .53
9.1 Acquiring PD measurements on windings and winding components.53
9.2 Identifying and locating the source of partial discharges.61
10 Interpretation of test results.63
10.1 General .63
10.2 Interpretation of PDIV, PDEV and Q .65
m
10.3 PD pattern recognition.69
11 Test report.73

Annex A (informative) On-line partial discharge measurements.79
Annex B (informative) Non-electrical methods of PD detection and methods for
localization .83
Annex C (informative) External noise, disturbance and sensitivity.85
Annex D (informative) Methods of disturbance suppression .91
Annex E (informative) Interpretation of PD magnitude data and phase resolved PD
patterns .103

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 5 –
Bibliography.111

Figure 1 – Frequency response of a PD pulse and coupling units of various time
constants .27
Figure 2 – Typical pulse responses of wide band and narrow band PD systems.31
Figure 3 – PD magnitude as a function of the normalized test voltage Q =f(U/U ) .35
m max
Figure 4 – Example of a φ-q-n partial discharge pattern where the PD was measured in
series with the test object in accordance with Figure 5b, with colour code for the pulse
number H(n) .37
Figure 5 – Basic test circuits in accordance with IEC 60270.41
Figure 6 – Test circuit for PD measurement (S1.1) on complete winding .43
Figure 7 – Normalization of the test circuit for measurement S1.1.51
Figure 8 – Test voltage applied to the test object during PD measurement .57
Figure 9 – Example for identification and localization of PD sources .71
Figure C.1 – Recharging of the test object by various current components.87
Figure D.1 – Without window masking.91
Figure D.2 – With window masking .91
Figure D.3 – Pulse currents through the measuring circuit .93
Figure D.4 – Example of noise rejection.99
Figure D.5 – Example of cross-talk rejection .101
Figure E.1 – Example PD patterns .105

Table 1 – Connection diagram S1 for open star point.45
Table 2 – Connection diagram S2 for closed star point .45
Table 3 – Connection diagram E1 for open star point.47
Table 4 – Connection diagram E2 for closed star point .47
Table E.1 – Risks associated with the main PD sources in rotating machines .107

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

ROTATING ELECTRICAL MACHINES –

Part 27: Off-line partial discharge measurements on the stator
winding insulation of rotating electrical machines


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 interna-
tional 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, Techni-
cal 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 organiza-
tions liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Or-
ganization 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 inter-
ested 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 misinter-
pretation 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 be-
tween any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equip-
ment declared to be in conformity with an IEC Publication.
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 ex-
penses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publica-
tions.
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.
The main task of IEC technical committees is to prepare International Standards. In excep-
tional circumstances, a technical committee may propose the publication of a technical speci-
fication when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 9 –
IEC 60034-27, which is a technical specification, has been prepared by IEC technical commit-
tee 2: Rotating machinery.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
2/1384/DTS 2/1395A/RVC

Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60034 series, under the general title Rotating electrical machines,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 11 –
INTRODUCTION
For many years, the measurement of partial discharges (PD) has been employed as a sensi-
tive means of assessing the quality of new insulation as well as a means of detecting local-
ized sources of PD in used electrical winding insulation arising from operational stresses in
service. Compared with other dielectric tests (i.e. the measurement of dissipation factor or
insulation resistance) the differentiating character of partial discharge measurements allows
localized weak points of the insulation system to be identified.
The PD testing of rotating machines is also used when inspecting the quality of new assem-
bled and finished stator windings, new winding components (e.g. form-wound coils and bars,
HV bushings, etc.) and fully impregnated stators.
In connection with the servicing and overhaul of rotating machines, the measurement of par-
tial discharges can also provide information on:
– points of weakness in the insulation system;
– ageing processes;
– further measures and intervals between overhauls.
Although the PD testing of rotating machines has gained widespread acceptance, it has
emerged from several studies that not only are there many different methods of measurement
in existence but also the criteria and methods of analysing and finally assessing the measured
data are often very different and not really comparable. Consequently, there is an urgent need
to give some guidance to those users who are considering the use of PD measurements to
assess the condition of their insulation systems.
Partial discharge testing of stator windings can be divided into two broad groups:
a) off-line measurements, in which the stator winding is isolated from the power system and
a separate power supply is employed to energize the winding;
b) on-line measurements, in which the rotating machine is operating normally and connected
to the power system.
Both of these approaches have advantages and disadvantages with respect to one another. A
brief discussion of the merits of on-line testing, as well as the drawbacks, is provided in
Annex A. However, while acknowledging the extensive world-wide use of on-line methods and
their proven value to industry, this technical specification is confined to off-line techniques.
This approach is considered necessary to render this specification sufficiently concise to be of
use by non-specialists in the field of PD testing.

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 13 –
Limitations:
When stator windings are being tested different types of PD measuring instruments will inevi-
tably produce different results and consequently PD measurements will only be comparable
under certain conditions. Therefore, absolute limits for the windings of rotating machines, for
example as acceptance criteria for production or operation, are difficult to define. This is
mainly due to pulse propagation phenomena, specific difficulties with calibration and the indi-
vidual frequency response characteristics of stator windings and PD measuring systems.
In addition, the degree of deterioration, and hence the risk of insulation system failure, de-
pends on the specific type of PD source and its location within the stator winding insulation,
both of which can influence the test results very significantly.
Empirical limits verified in practice can be used as a basis for evaluating test results. Fur-
thermore, PD trend evaluation and comparisons with machines of similar design and similar
insulation system measured under similar conditions, using the same measurement equip-
ment, are recommended to ensure reliable assessment of the condition of the stator winding
insulation.
Users of PD measurement should be aware that, due to the principles of the method, not all
insulation-related problems in stator windings can be detected by measuring partial dis-
charges (e.g. insulation failures involving continuous leakage currents due to conductive
paths between different elements of the insulation or pulseless discharge phenomena).
For testing individual winding components, the limitations due to pulse propagation phenom-
ena need not be considered when interpreting the results of measurements.

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 15 –
ROTATING ELECTRICAL MACHINES –

Part 27: Off-line partial discharge measurements on the stator
winding insulation of rotating electrical machines



1 Scope
This part of IEC 60034 which is a technical specification provides a common basis for
– measuring techniques and instruments,
– the arrangement of test circuits,
– normalization and testing procedures,
– noise reduction,
– the documentation of test results,
– the interpretation of test results
with respect to partial discharge off-line measurements on the stator winding insulation of
rotating electrical machines when tested with alternating voltages up to 400 Hz. This technical
specification applies to rotating machines having bars or form wound coils with conductive
slot coating. This is usually valid for machines with voltage rating of 6 kV and higher. The
measurement methods described in this specification may also be applied to machines with-
out conductive slot coating. However, results may be different and are not covered by this
specification.
2 Normative references
The following referenced documents are indispensable for the application 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 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60060-2, High-voltage test techniques – Part 2: Measuring systems
IEC 60270:2000, High-voltage test techniques – Partial discharge measurements
3 Terms and definitions
For the purposes of this document, the general terms and definitions for partial discharge
measurements given in IEC 60270 apply, together with the following.
3.1
off-line measurement
measurement taken with the rotating machine at standstill, the machine being disconnected
from the power system
NOTE The necessary test voltage is applied to the winding from a separate voltage source.

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 17 –
3.2
on-line measurement
measurement taken with the rotating machine in normal operation
3.3
stress control coating
paint or tape on the surface of the groundwall insulation that extends beyond the conductive
slot portion coating in high-voltage stator bars and coils
NOTE The stress control coating reduces the electric field stress along the winding overhang to below a critical
value that would initiate PD on the surface. The stress control coating overlaps the conductive slot portion coating
to provide electrical contact between them.
3.4
conductive slot coating
conductive paint or tape layer in intimate contact with the groundwall insulation in the slot
portion of the coil side, often called semiconductive coating
NOTE This coating provides good electrical contact to the stator core.
3.5
resistance temperature detector
RTD
a temperature detector inserted into the stator winding, usually between the top and bottom
bar or embedded coil sides in a given slot
3.6
slot discharges
discharges that occur between the outer surface of the slot portion of a coil or bar and the
grounded core laminations
3.7
internal discharges
discharges that occur within the insulation system
3.8
surface discharges
discharges that occur on the surface of the insulation or on the surface of winding compo-
nents in the winding overhang or the active part of the machine winding
3.9
pulse height distribution
the number of pulses within a series of equally-spaced windows of pulse magnitude during a
predefined measuring time
3.10
pulse phase distribution
the number of pulses within a series of equally-spaced windows of phase during a predefined
measuring time
3.11
partial discharge pattern
PD distribution map of PD magnitude vs a.c. cycle phase position, for visualization of the PD
behaviour during a predefined measuring time, in which specific PD parameters are used for
graphical representation

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SIST-TS CLC/TS 60034-27:2011
TS 60034-27 © IEC:2006 – 19 –
3.12
coupling device
usually an active or passive four-terminal network that converts the input currents to output
voltage signals
NOTE These signals are transmitted to the measuring instrument by a transmission system. The frequency re-
sponse of the coupling device is normally chosen at least so as to efficiently prevent the test voltage frequency and
its harmonics from reaching the measuring instrument.
3.13
PD coupling unit
a high voltage coupling capacitor of low inductance design and a low voltage coupling device
in series
3.14
largest repeatedly occurring PD magnitude
Q
m
the largest magnitude recorded by a measuring system which has the pulse train response in
accordance with 4.3.3 of IEC 60270, or the magnitude associated with a PD pulse repetition
rate of 10 pulses per second (pps), which can be directly inferred from a pulse height distribu-
tion
3.15
normalized quantity number
NQN
normalized area under a straight line fitted to the pulse counts in each magnitude window of a
pulse height analysis, in which the pulse counts are expressed as a logarithm of the pulses
per second and the pulse magnitude window is a linear scale
4 Nature of PD in rotating machines
4.1 Basics of PD
Generally, partial discharges (PD) can develop at locations where the dielectric properties of
insulating materials are inhomogeneous. At such locations, the local electrical field strength
may be enhanced. Due to local electrical over-stressing this may lead to a local, partial
breakdown. This partial breakdown does not result in a total breakdown of the insu
...