IEC 60931-2:2025

IEC 60931-2 ®
Edition 3.0 2025-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Shunt power capacitors of the non-self-healing type for AC systems having a
rated voltage up to and including 1 000 V –
Part 2: Ageing test and destruction test
Condensateurs shunt de puissance non autorégénérateurs pour réseaux à
courant alternatif de tension assignée inférieure ou égale à 1 000 V –
Partie 2: Essais de vieillissement et de destruction
ICS 29.120.99, 31.060.70 ISBN 978-2-8327-0495-0
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either
IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC copyright
or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local
IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - IEC Products & Services Portal - products.iec.ch
webstore.iec.ch/advsearchform Discover our powerful search engine and read freely all the
The advanced search enables to find IEC publications by a publications previews, graphical symbols and the glossary.
variety of criteria (reference number, text, technical With a subscription you will always have access to up to date
committee, …). It also gives information on projects, content tailored to your needs.

replaced and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published containing more than 22 500 terminological entries in English
details all new publications released. Available online and and French, with equivalent terms in 25 additional languages.
Also known as the International Electrotechnical Vocabulary
once a month by email.
(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer
Service Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC -  IEC Products & Services Portal - products.iec.ch
webstore.iec.ch/advsearchform Découvrez notre puissant moteur de recherche et consultez
La recherche avancée permet de trouver des publications gratuitement tous les aperçus des publications, symboles
IEC en utilisant différents critères (numéro de référence, graphiques et le glossaire. Avec un abonnement, vous aurez
texte, comité d’études, …). Elle donne aussi des toujours accès à un contenu à jour adapté à vos besoins.
informations sur les projets et les publications remplacées
ou retirées. Electropedia - www.electropedia.org
Le premier dictionnaire d'électrotechnologie en ligne au
IEC Just Published - webstore.iec.ch/justpublished monde, avec plus de 22 500 articles terminologiques en
Restez informé sur les nouvelles publications IEC. Just anglais et en français, ainsi que les termes équivalents
Published détaille les nouvelles publications parues. dans 25 langues additionnelles. Egalement appelé
Disponible en ligne et une fois par mois par email. Vocabulaire Electrotechnique International (IEV) en ligne.

Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-
nous: sales@iec.ch.
CONTENTS
FOREWORD. 2
1 Scope . 4
2 Normative references . 4
6 Tests . 4
6.12 Ageing test . 4
6.12.1 Conditioning . 4
6.12.2 Test sequence . 5
6.12.3 Test requirements . 6
6.13 Destruction test . 6
6.13.1 General . 6
6.13.2 Test sequence . 6
6.13.3 Test requirements . 8

Figure 1 – Circuit to perform the destruction test . 7

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Shunt power capacitors of the non-self-healing type for AC systems
having a rated voltage up to and including 1 000 V –
Part 2: Ageing test and destruction test

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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60931-2 has been prepared by technical committee 33: Power capacitors and their
applications. It is an International Standard.
This third edition cancels and replaces the second edition published in 1995. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Deletion of self-healing test.
This International Standard is to be used in conjunction with IEC 60931-1:2025. The numbering
of the clauses and subclauses in this document corresponds to that of IEC 60931-1:2025.
The text of this International Standard is based on the following documents:
Draft Report on voting
33/709/CDV 33/716/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 60931 series, published under the general title Shunt power
capacitors of the non-self-healing type for AC systems having a rated voltage up to and
including 1 000 V, 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 webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
1 Scope
This part of IEC 60931 applies to capacitors according to IEC 60931-1 and gives the
requirements for the ageing test and destruction test for these capacitors.
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 60931-1:2025, Shunt power capacitors of the non-self-healing type for AC systems having
a rated voltage up to and including 1 000 V – Part 1: General
6 Tests
6.12 Ageing test
6.12.1 Conditioning
6.12.1.1 General
The temperature of the case during the first part (6.12.2 a)) and the third part (6.12.2 c)) of the
ageing test shall be the highest mean temperature in 24 h (see IEC 60931-1:2025, Table 1)
plus the difference between the measured temperature of the case and the cooling air
temperature recorded at the end of the thermal stability test carried out on an identical unit. The
second part (6.12.2 b)) of the ageing test should be performed at room temperature.
The two test methods indicated below are intended to ensure that the capacitor case
temperature is maintained constant during the test.
The two methods are considered as being equivalent.
The units that are not sealed shall be tested in air, with forced circulation.
6.12.1.2 Testing in air with forced circulation
The capacitor unit is mounted in an enclosure in which heated air is circulated with an air
velocity such that temperature variations at any point of the enclosure do not exceed ±2 °C.
The sensitive element of the thermostat regulating the temperature in the capacitor enclosure
shall be located on the surface of the capacitor container, three-quarters of the way up.
The capacitor shall be placed in a vertical position with the terminals upright.
When many capacitors are tested together, they shall be placed with sufficient clearance
between them in order to have sufficient temperature uniformity.
After placing the capacitor in the unheated enclosure, the thermostat shall be set at a
temperature equal to that indicated in 6.12.1.1.
Then, without energizing the capacitor, the enclosure shall be brought to thermal stability, which
shall be deemed to have been reached when the container temperature of the capacitor has
reached the stated temperature with a tolerance of ±2 °C.
The capacitor shall then be energized at the voltage stated in 6.12.2 a).
6.12.1.3 Testing in a liquid bath
The capacitor unit is immersed in a container filled with a liquid which, by appropriate heating,
is kept at the temperature indicated in 6.12.1.1 during the whole test.
This temperature is maintained with a permissible change of ±2 °C.
Care shall be taken to ensure that the temperature in the neighbourhood of the capacitor is
within these limits.
The capacitor is not energized until it has reached the temperature of the liquid bath.
The capacitor shall then be energized at the voltage stated in 6.12.2 a).
Where the terminal insulation, or the insulation of cables permanently attached to the capacitor,
is of material that might be damaged by the heating liquid, it is permissible for the capacitors to
be positioned in such a manner that these terminals or cables are just above the surface of the
liquid.
6.12.2 Test sequence
Before the test, the capacitance shall be measured as prescribed in 6.2.1 of IEC 60931-1:2025.
The test sequence is in three parts as follows:
a) The capacitor shall be energized at a voltage equal to 1,25 U for 750 h. Taking the
N
tolerances of the supply voltage into account, this test voltage shall be the average voltage
for the whole test duration.
b) The capacitor shall then be subjected to 1 000 discharge cycles consisting of:
• charging the capacitor to a DC voltage of 2 U ;
N
• discharging the capacitor through an inductance of:
L ±20% in microhenrys (µH)
C
in which C is the measured capacitance in microfarads (µF).
The cables used for the external circuit and the inductance shall have a cross-section
appropriate to the maximum permissible current (see IEC 60931-1:2025, Clause 8).
The duration of each cycle shall be 30 s minimum.
The connection for this part of the test shall be as described in 6.11 of IEC 60931-1:2025.
c) Repetition of item a).
During the whole test sequence the temperature of the case shall be maintained equal to
that indicated in 6.12.1.
In the case of three-phase capacitors, the first and the third parts of the test sequence (items
(a) and (c)) shall be carried out with all the phases energized at 1,25 U . This can be
N
obtained either by using a three-phase source, or by using a monophase source and
modifying the internal capacitor connections.
Due to the long duration of this test, voltage interruptions may occur unexpectedly. During
these interruptions, the capacitor units shall remain in the same test setup and the test time
is also interrupted. If power is interrupted to the heating enclosure, the ageing test shall
resume with the same starting conditions as described in 6.12.1.2 or 6.12.1.3.
=
6.12.3 Test requirements
During the test no permanent breakdown, interruption or flashover shall occur.
At the end of the test the capacitor shall cool down freely to the ambient temperature and the
capacitance shall then be measured under the same conditions as before the test.
The maximum permitted variation of capacitance compared to the values measured before the
test shall be 3 % averaged over all the phases and 5 % on one phase.
The voltage test between terminals and container shall be carried out with the same procedures
as prescribed in 6.5.1 of IEC 60931-1:2025.
The sealing test shall be repeated as prescribed in 6.7 of IEC 60931-1:2025.
6.13 Destruction test
6.13.1 General
This test is performed to evaluate the behaviour of the capacitor at the end of its life.
If the capacitor is protected by internal fuses, the destruction test does not apply.
If no internal fuses are provided, the destruction test shall be carried out according to the
following procedure.
6.13.2 Test sequence
The test shall be carried out on a capacitor unit. If necessary the discharge resistors shall be
disconnected in order to avoid burning.
A capacitor which has passed the ageing test may be used.
For polyphase units the test shall be carried out between two terminals only. In the case of
three-phase delta connection two terminals shall be short-circuited. For star connection no
terminals shall be short-circuited.
The principle of the test is to promote failure in the elements by DC voltage and subsequently
to check the behaviour of the capacitor when an AC voltage is applied.
The capacitor shall be mounted in a circulating air oven having a temperature equal to the
maximum ambient air temperature of the temperature category of the capacitor.
When all the parts of the capacitor have reached the temperature of the oven the following test
sequence shall be performed with the circuit given in Figure 1.
a) With the selector switches H and K in position 1 and a respectively, the AC voltage source
and the capacitor current is recorded.
is set to 1,3 U
N
b) The DC source is set to 10 U . The switch H is then set to position 2 and the variable
N
resistor is adjusted to give a DC short-circuit current of 300 mA.
c) Switch H is set to position 3 and switch K to position b in order to apply the DC test voltage
to the capacitor which is maintained until the voltmeter indicates approximately zero for at
least 3 s.
d) Switch K is then set to position a again in order to apply the AC test voltage to the capacitor
for a period of 3 min when the current is again noted.
The following conditions may be obtained:
• the ammeter I and the voltmeter U both indicate zero. In this case the fuse shall be checked.
If it has blown it shall be replaced. Then the AC voltage is applied to the capacitor and if the
fuse blows again the procedure is interrupted. If the fuse does not blow, the procedure
consisting in the application to the capacitor of DC and AC voltage as prescribed in items
c) and d) continues using only the switch K;
• the current indicated by the ammeter I is lower than 66 % of the initial value and the
voltmeter U indicates 1,3 U . In this case the procedure is interrupted;
N
• the current indicated by the ammeter I is higher than 66 % of the initial value. In this case
the procedure (DC-AC) continues.
When the procedure is interrupted the capacitor is cooled to the ambient temperature, and the
voltage test between terminals and container is carried out according to 6.5.1 of
IEC 60931-1:2025 applying an AC voltage of 1 500 V.

Figure 1 – Circuit to perform the destruction test
The minimum short-circuit current of the AC generator shall be 2 000 A at the capacitor
terminals.
A time-lag fuse-link for protecting the setup shall be used.
The rated current I of the fuse shall be obtained by the formula:
F
I = K I ± 10 % in amperes (A)
F
where:
K = 100 / Q
Q = Q in kilovars (kvar), in the case of a single-phase capacitor;
N
Q = 2/3 I in kilovars (kvar), in the case of a three-phase delta-connected capacitor with two
N
terminals connected together or three-phase star-connected capacitor with two terminals
connected only. (This because the testing voltage has to be adjusted as per additional
note when performing the test; see NOTE);
I = I in amperes (A), in the case of a sing
...