IEC TS 60815-3:2008

IEC/TS 60815-3
Edition 1.0 2008-10
TECHNICAL
SPECIFICATION
Selection and dimensioning of high-voltage insulators intended for use in
polluted conditions –
Part 3: Polymer insulators for a.c. systems

IEC/TS 60815-3:2008(E)
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 la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC/TS 60815-3
Edition 1.0 2008-10
TECHNICAL
SPECIFICATION
Selection and dimensioning of high-voltage insulators intended for use in
polluted conditions –
Part 3: Polymer insulators for a.c. systems

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
R
ICS 29.080.10 ISBN 978-2-88910-303-4
– 2 – TS 60815-3 © IEC:2008(E)
CONTENTS
FOREWORD.3
1 Scope and object.5
2 Normative references .5
3 Terms, definitions and abbreviations .6
3.1 Terms and definitions .6
3.2 Abbreviations .6
4 Principles .6
5 Materials .7
5.1 General information on common polymer housing materials .7
5.2 Issues specific to polymer housing materials under pollution .7
5.2.1 Reduction of creepage distance.7
5.2.2 Extreme pollution.8
6 Site severity determination .9
7 Determination of the reference USCD.9
8 General recommendations for polymer profiles .10
9 Checking of profile parameters .11
9.1 General remark .11
9.2 Alternating sheds and shed overhang.12
9.3 Spacing versus shed overhang.12
9.4 Minimum distance between sheds .13
9.5 Creepage distance versus clearance .13
9.6 Shed angle.14
9.7 Creepage factor .14
10 Correction of RUSCD .14
10.1 Correction for altitude K .14
a
10.2 Correction for insulator diameter K .15
ad
11 Determination of the final minimum creepage distance .15
12 Confirmation by testing.15
Annex A (informative) Background information on pollution induced degradation of
polymers.17
Bibliography.20

Figure 1 – RUSCD as a function of SPS class .9
Figure 2 – Typical “open” profiles.10
Figure 3 – Typical steep polymeric profile .10
Figure 4 – Typical shallow under-ribs on open profile .10
Figure 5 – Typical deep under-rib profile.11
Figure 6 – Typical “alternating” profiles .11
Figure 7 – K versus average diameter and illustration of parameters.15
ad
Figure A.1 – Operating areas as a function of pollution severity and USCD (for a fixed
insulating length) .19

TS 60815-3 © IEC:2008(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SELECTION AND DIMENSIONING OF HIGH-VOLTAGE INSULATORS
INTENDED FOR USE IN POLLUTED CONDITIONS –

Part 3: Polymer insulators for a.c. systems

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment 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
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.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification 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.
IEC/TS 60815-3, which is a technical specification, has been prepared by technical
committee 36: Insulators.
– 4 – TS 60815-3 © IEC:2008(E)
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
36/266/DTS 36/272A/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 the parts in the future IEC 60815 series, under the general title Selection and
dimensioning of high-voltage insulators intended for use in polluted conditions, 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.
A bilingual version of this publication may be issued at a later date.

TS 60815-3 © IEC:2008(E) – 5 –
SELECTION AND DIMENSIONING OF HIGH-VOLTAGE INSULATORS
INTENDED FOR USE IN POLLUTED CONDITIONS –

Part 3: Polymer insulators for a.c. systems

1 Scope and object
IEC/TS 60815-3, which is a technical specification, is applicable to the selection of polymer
insulators for a.c. systems, and the determination of their relevant dimensions, to be used in
high voltage systems with respect to pollution.
This part of IEC/TS 60815 gives specific guidelines and principles to arrive at an informed
judgement on the probable behaviour of a given insulator in certain pollution environments.

The contents of this technical specification are based on CIGRE 33.13 TF 01 documents [1],
[2] , which form a useful complement to this technical specification for those wishing to study
in greater depth the performance of insulators under pollution.
This technical specification does not deal with the effects of snow or ice on polluted
insulators. Although this subject is dealt with by CIGRE [3], current knowledge is very limited
and practice is too diverse.
The object of this technical specification is to give the user means to
• determine the reference unified specific creepage distance (USCD) from site pollution
severity (SPS) class,
• choose appropriate profiles,
• apply correction factors for altitude, insulator shape, size and position, etc. to the
referenc
...