IEC TR 62271-307:2024

High-voltage switchgear and controlgear - Part 307: Guidance for the extension of validity of type tests of AC metal and solid-insulation enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV

IEC TR 62271-307:2024 refers to prefabricated metal-enclosed and solid-insulation enclosed (both hereinafter called enclosed) switchgear and controlgear assemblies for alternating current of rated voltages above 1 kV and up to and including 52 kV as specified in IEC 62271‑200 and IEC 62271‑201, and to other equipment included in the same enclosure with any possible mutual influence. This second edition cancels and replaces the first edition published in 2015. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) Structure of document updated.
b) Updated references to IEC 62271-200:2021 and IEC 62271-1:2017.
c) Addition of criteria for the extension of validity of type tests from functional unit(s) with a different insulating gas to the functional unit to be validated.
d) Figure 5 for the validation of a design modification was added.
e) Clause B.7 for the extension of validity of type test for a GIS with insulation gas A to insulation gas B was added.

Appareillage à haute tension - Partie 307: Lignes directrices pour l'extension de validité des essais de type d'appareillages en courant alternatif sous enveloppe métallique et d'isolation solide pour tensions assignées supérieures à 1 kV et jusqu'à 52 kV inclus

General Information

• Status: Published
• Publication Date: 04-Dec-2024
• ICS: 29.130.10 - High voltage switchgear and controlgear
• Technical Committee: SC 17C - Assemblies
• Drafting Committee: MT 43 - TC 17/SC 17C/MT 43
• Current Stage: PPUB - Publication issued
• Start Date: 08-Nov-2024
• Completion Date: 05-Dec-2024

Relations

• Revises: IEC TR 62271-307:2015 - High-voltage switchgear and controlgear - Part 307: Guidance for the extension of validity of type tests of AC metal and solid-insulation enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 62271-307 ®
Edition 2.0 2024-12
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
High- voltage switchgear and controlgear –
Part 307: Guidance for the extension of validity of type tests of AC metal and
solid-insulation enclosed switchgear and controlgear for rated voltages above
1 kV and up to and including 52 kV

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.

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

IEC Just Published - webstore.iec.ch/justpublished
Electropedia - www.electropedia.org
Stay up to date on all new IEC publications. Just Published
The world's leading online dictionary on electrotechnology,
details all new publications released. Available online and once
containing more than 22 500 terminological entries in English
a month by email.
and French, with equivalent terms in 25 additional languages.

Also known as the International Electrotechnical Vocabulary
IEC Customer Service Centre - webstore.iec.ch/csc
(IEV) online.
If you wish to give us your feedback on this publication or need

further assistance, please contact the Customer Service
Centre: [e-mail].
IEC TR 62271-307 ®
Edition 2.0 2024-12
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
High- voltage switchgear and controlgear –
Part 307: Guidance for the extension of validity of type tests of AC metal and
solid-insulation enclosed switchgear and controlgear for rated voltages above
1 kV and up to and including 52 kV
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.130.10 ISBN 978-2-8327-0085-3

– 2 – IEC TR 62271-307:2024 RLV © IEC 2024
CONTENTS
FOREWORD . 6
1 General .
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Use of extension criteria . 11
4.1 General . 11
4.2 Parameters for extension criteria . 11
4.3 Use of calculations . 12
4.3.1 General . 12
4.3.2 Temperature rise calculations . 13
4.3.3 Electric field calculations . 13
4.3.4 Mechanical stress calculations. 13
4.3.5 Short-circuit current calculations . 13
4.3.6 Internal arc pressure rise calculations . 14
4.4 Information needed for extension of type test validity . 14
4.5 Extension of validity when using different insulating gas or gas mixture . 14
5 Application of extension criteria . 15
5.1 General . 15
5.2 Dielectric tests . 15
5.3 Temperature rise Continuous current tests . 18
5.4 Mechanical tests . 20
5.5 Short-time withstand current and peak withstand current tests . 21
5.6 Making and breaking tests . 22
5.7 Internal arc fault tests . 23
5.7.1 General . 23
5.7.2 Extension criteria with respect to the switchgear and controlgear design . 24
5.7.3 Extension criteria with respect to ratings and installation conditions . 25
6 Extending Typical processes for the application of the extension of the validity of
type tests . 26
6.1 General . 26
6.2 Extension of validity of a test report to other functional units (situation a) . 26
6.3 Validation of a family by selection of test objects (situation b) . 29
6.3.1 General . 29
6.3.2 Mapping of the family . 30
6.3.3 Specification of test objects . 31
6.4 Validation of an assembly by existing test reports (situation c) . 31
6.5 Validation of a design modification (situation d) . 33
Annex A (informative) Rationale for the extension criteria . 35
A.1 General . 35
A.2 Dielectric tests . 35
A.2.1 General . 35
A.2.2 Clearances (items 1 and 2) . 35
A.2.3 Insulating supports and material (items 3 and 4) . 35
A.2.4 Live parts (items 5 and 6) . 36
A.2.5 Open contact gap and isolating distance (items 7 and 8) . 36

A.2.6 Minimum functional pressure for insulation (item 9) . 36
A.2.7 Minimum ambient temperature in service (item 10) . 36
A.2.8 Minimum dielectric properties of insulation gas or gas mixture (item 11) . 37
A.3 Temperature rise Continuous current tests . 37
A.3.1 General . 37
A.3.2 Centre distance between phase conductors (item 1) . 37
A.3.3 Phase to earth distance (item 2) . 38
A.3.4 Enclosure and compartment volume (item 3) . 38
A.3.5 Pressure (density) of insulating gas (item 4) . 38
A.3.6 Conductors (items 5 and 6) . 38
A.3.7 Conductor joints and connections (items 7, 8 and 9) . 39
A.3.8 Ventilation area of partitions and enclosure (item 10) . 39
A.3.9 Power dissipation of components (item 11) . 39
A.3.10 Insulating barriers (Item 12) . 40
A.3.11 Insulating coating of conductors and enclosures (items 13 and 14) . 40
A.3.12 Insulating material in contact with conductors (item 15) . 40
A.3.13 Minimum thermal performance of gas or gas mixture (item 16) . 40
A.4 Mechanical tests . 41
A.4.1 General . 41
A.4.2 Shutter systems (item 1) . 41
A.4.3 Contacts of removable parts (item 2) . 42
A.4.4 Interlocking systems (items 3 and 4) . 42
A.5 Short-time withstand current and peak withstand current tests . 43
A.5.1 General . 43
A.5.2 Centre distance between phase conductors (item 1) . 43
A.5.3 Conductors (items 2, 5 and 6) . 43
A.5.4 Insulating conductor supports (items 3 and 4) . 44
A.5.5 Insulating material in contact with conductors (item 7) . 44
A.5.6 Enclosure, partitions or bushings (item 8) . 44
A.5.7 Contacts of removable part (item 9) . 44
A.6 Making and breaking tests . 44
A.6.1 General . 44
A.6.2 Clearance between phases and to earth (items 1 and 2) . 45
A.6.3 Enclosure and compartment volume (item 3) . 45
A.6.4 Insulating gas (item 4) . 45
A.6.5 Conductors (items 5 and 6) . 45
A.6.6 Insulating supports (items 7, 8 and 9) . 46
A.6.7 Dielectric withstand capability (item 10) . 46
A.7 Internal arc fault tests . 46
A.7.1 General . 46
A.7.2 Clearance between phases and to earth (items 1 and 2) . 46
A.7.3 Compartment volume (item 3) . 47
A.7.4 Pressure of insulating gas (item 4) . 47
A.7.5 Material in the region of arc initiation (items 5, 6, 7 and 8) . 47
A.7.6 Pressure relief opening devices (items 9, 10 and 11) . 48
A.7.7 Enclosure and compartments (items 12, 13, 14 and 15) . 48
A.8 Rationale for extension criteria with respect to arc fault ratings and

installation conditions . 48
A.8.1 General . 48

– 4 – IEC TR 62271-307:2024 RLV © IEC 2024
A.8.2 Rated arc fault current and duration (items 1 and 2) . 49
A.8.3 Rated voltage (item 3) . 49
A.8.4 Rated frequency (item 4) . 49
A.8.5 Arrangement of assembly (items 5, 6 and 7) . 49
A.8.6 Indoor or outdoor installa
...