IEC TR 62271-305:2009

IEC/TR 62271-305 ®
Edition 1.0 2009-11
TECHNICAL
REPORT
colour
inside
High-voltage switchgear and controlgear –
Part 305: Capacitive current switching capability of air-insulated disconnectors
for rated voltages above 52 kV

IEC/TR 62271-305:2009(E)
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IEC/TR 62271-305 ®
Edition 1.0 2009-11
TECHNICAL
REPORT
colour
inside
High-voltage switchgear and controlgear –
Part 305: Capacitive current switching capability of air-insulated disconnectors
for rated voltages above 52 kV

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
Q
ICS 29.130.10 ISBN 978-2-88910-659-2
– 2 – TR 62271-305 © IEC:2009(E)
CONTENTS
FOREWORD.3
1 Scope.5
2 Normative references .5
3 Terms and definitions .5
4 Background and purpose.5
5 Switching tests .5
5.1 Arrangement of the disconnector for tests .5
5.2 Earthing of the test circuit and disconnector .6
5.3 Test frequency .6
5.4 Test voltage .6
5.5 Test current.6
5.6 Test circuit .6
5.7 Tests.7
5.7.1 Test duties and measurements .7
5.7.2 Behaviour of disconnector during tests .8
5.7.3 Condition of disconnector after tests.8
5.8 Test reports.8
Annex A (informative) Analysis .9
Annex B (informative) Capacitive charging currents .14
Annex C (informative) Test circuits .15

Figure 1 – Test circuit in principle for capacitive current switching .7
Figure A.1 – Basic capacitive current switching circuit .9
Figure A.2 – Test oscillograms for current of 2 A and C /C ratios of 2,5 (Trace A) and
S L
0,04 (Trace B).10
Figure A.3 – Circuit for restriking current calculation.12
Figure C.1 – Basic capacitive current switching circuit .15
Figure C.2 – Alternative test circuit .16
Figure C.3 – Restriking and integrated currents (in A and As, respectively) for the
basic (dashed) traces) and alternative circuits (drawn traces). Horizontal axis in ms.17

Table 1 – Test tolerances .7
Table B.1 – Capacitive charging currents at 245 kV and below .14
Table B.2 – Capacitive charging currents at 300 kV to 550 kV .14
Table B.3 – Capacitive charging currents at 800 kV to 1200 kV .14

TR 62271-305 © IEC:2009(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 305: Capacitive current switching capability of air-insulated
disconnectors for rated voltages above 52 kV

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
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data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62271-305, which is a technical report, has been prepared by subcommittee 17A: High-
voltage switchgear and controlgear, of IEC technical committee 17: Switchgear and
controlgear.
– 4 – TR 62271-305 © IEC:2009(E)
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
17A/872/DTR 17A/885/RVC
Full information on the voting for the approval of this technical report 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 62271 series, published under the general title High-voltage
switchgear and controlgear, 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
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
The contents of the corrigendum of June 2017 have been included in this copy.

IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

TR 62271-305 © IEC:2009(E) – 5 –
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 305: Capacitive current switching capability of air-insulated
disconnectors for rated voltages above 52 kV

1 Scope
This technical report applies to high-voltage air-insulated disconnectors for rated voltages
above 52 kV. The report describes the capacitive current switching duty and provides
guidance on laboratory testing to demonstrate the switching capability. Air-insulated
disconnectors equipped with auxiliary interrupting devices are included under this scope.
NOTE For manually operated disconnectors, the in-service safety of the operator should be considered and it
should be recognized that the results of the switching tests described herein (performed using motor-operated
disconnectors) are not necessarily representative of the performance of such disconnectors in actual service. Due
diligence should be exercised if the switching tests indicate that prolonged arc durations are probable.
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 62271-1: High-voltage switchgear and controlgear – Part 1: Common specifications
IEC 62271-102:2001 High-voltage switchgear and controlgear – Part 102: Alternating current
disconnectors and earthing switches
3 Terms and definitions
For purposes of this part of IEC 62271 the terms and definitions in IEC 62271-1 and
IEC 62271-102 apply.
4 Background and purpose
Disconnectors do not have current interrupting ratings but, by virtue of having one or more
moving contacts during opening operations, they have a certain current switching capability.
For capacitive currents and air-insulated disconnectors, this capability has in the past been
taken as 0,5 A or less and no testing was defined. For gas-insulated disconnectors, the
required capacitive current switching capability and test requirements are specified in
Annex F of IEC 62271-102.
User requirements for capacitive current switching using air-insulated disconnectors
frequently exceed the above-stated 0,5 A. The purpose, therefore, of this report is to provide
an analysis of the switching duty (refer to Annex A) and to define testing procedures.
5 Switching tests
5.1 Arrangement of the disconnector for tests
The disconnector under test should be completely mounted on its own support or on an
equivalent support. For safety reasons and to obtain consistent results, only motor operation
should be used. Motor operation should be at the minimum supply voltage.

– 6 – TR 62271-305 © IEC:2009(E)
Before commencing switching tests, resistance measurement of the main circuit and no-load
operations should be made and details of the operating characteristics of the disconnector
such as contact separation (arc initiation), closing time and opening time, should be recorded.
Only singe-phase tests on one pole of a three-pole disconnector need be performed provided
that the pole is not in a more favourable condition than the complete three-pole disconnector
with respect to
• closing time;
• opening time;
• influence of adjacent phases.
NOTE Single-phase tests are adequate to demonstrate the switching performance of a disconnector provided that
the arcing time and arc reach are such that there is no possibility of involvement of an adjacent phase. If excessive
arc reach is encountered during single-phase testing, then three-phase testing should be performed. A reach of the
tip of the arc towards an adjacent phase equal to or greater than half the metal-to-metal spacing between phases is
to be considered as excessive.
5.2 Ea
...