EN 62271-204:2011

SLOVENSKI STANDARD
01-november-2011
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High-voltage switchgear and controlgear - Part 204: Rigid high-voltage, gas-insulated
transmission lines for rated voltages of 72,5 kV and above (IEC 62271-204:2011)
Hochspannungs-Schaltgeräte und -Schaltanlagen - Teil 204: Starre gasisolierte
Hochspannungs-Übertragungsleitungen für Bemessungsspannungen über 52 kV (IEC
62271-204:2011)
Appareillage à haute tension - Part 204: Lignes de transport rigides haute tension à
isolation gazeuse de tension assignée égale ou supérieure à 72, 5 kV (CEI 62271-
204:2011)
Ta slovenski standard je istoveten z: EN 62271-204:2011
ICS:
29.130.10 Visokonapetostne stikalne in High voltage switchgear and
krmilne naprave controlgear
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62271-204
NORME EUROPÉENNE
September 2011
EUROPÄISCHE NORM
ICS 29.130.10
English version
High-voltage switchgear and controlgear -
Part 204: Rigid gas-insulated transmission lines
for rated voltage above 52 kV
(IEC 62271-204:2011)
Appareillage à haute tension -  Hochspannungs-Schaltgeräte und -
Part 204: Lignes de transport rigides à Schaltanlagen -
isolation gazeuse de tension assignée Teil 204: Starre gasisolierte
supérieure à 52 kV Übertragungsleitungen für
(CEI 62271-204:2011) Bemessungsspannungen über 52 kV
(IEC 62271-204:2011)
This European Standard was approved by CENELEC on 2011-08-30. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

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. EN 62271-204:2011 E
Foreword
The text of document 17C/510/FDIS, future edition 1 of IEC 62271-204, prepared by SC 17C,
"High-voltage switchgear and controlgear assemblies", of IEC TC 17, "Switchgear and controlgear" was
submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 62271-204:2011.

The following dates are fixed:
(dop) 2012-05-30
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2014-08-30
• latest date by which the national
standards conflicting with the
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
Endorsement notice
The text of the International Standard IEC 62271-204:2011 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
[1] IEC 60071-1 NOTE  Harmonized as EN 60071-1.

- 3 - EN 62271-204:2011
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 60050-151 - International Electrotechnical Vocabulary - -
(IEV) -
Part 151: Electrical and magnetic devices

IEC 60050-441 1984 International Electrotechnical Vocabulary - -
(IEV) -
Chapter 441: Switchgear, controlgear and
fuses
IEC 60060-1 - High-voltage test techniques - EN 60060-1 -
Part 1: General definitions and test
requirements
IEC 60068-1 - Environmental testing - EN 60068-1 -
Part 1: General and guidance
IEC 60229 2007 Tests on cable oversheaths which have a EN 60229 2008
special protective function and are applied by
extrusion
IEC 60270 - High-voltage test techniques - Partial EN 60270 -
discharge measurements
IEC 60287-3-1 1995 Electric cables - Calculation of the current - -
rating -
Part 3: Sections on operating conditions -
Section 1: Reference operating conditions and
selection of cable type
IEC 60376 - Specification of technical grade sulfur EN 60376 -
hexafluoride (SF ) for use in electrical
equipment
IEC 60480 - Guidelines for the checking and treatment of EN 60480 -
sulphur hexafluoride (SF ) taken from
electrical equipment and specification for its
re-use
IEC 60529 1989 Degrees of protection provided by enclosures EN 60529 1991
(IP Code) + corr. May 1993
IEC 62271-1 2007 High-voltage switchgear and controlgear - EN 62271-1 2008
Part 1: Common specifications
1) 1)
IEC 62271-203 201X High-voltage switchgear and controlgear - EN 62271-203 201X
Part 203: Gas-insulated metal-enclosed
switchgear for rated voltages above 52 kV

IEC/TR 62271-303 - High-voltage switchgear and controlgear - CLC/TR 62271-303 -
Part 303: Use and handling of sulphur
hexafluoride (SF6)
1)
To be published.
Publication Year Title EN/HD Year

ISO/IEC Guide 51 - Safety aspects - Guidelines for their inclusion - -
in standards
IEC 62271-204 ®
Edition 1.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage switchgear and controlgear –
Part 204: Rigid gas-insulated transmission lines for rated voltage above 52 kV

Appareillage à haute tension –
Partie 204: Lignes de transport rigides à isolation gazeuse de tension assignée
supérieure à 52 kV
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XA
ICS 29.130.10 ISBN 978-2-88912-604-0

– 2 – 62271-204  IEC:2011
CONTENTS
FOREWORD . 5
1 General . 7
1.1 Scope . 7
1.2 Normative references . 7
2 Normal and special service conditions . 8
2.101 Installation in open air . 8
2.102 Buried installation . 9
2.103 Installation in tunnel, shaft or similar situation . 9
3 Terms and definitions . 9
4 Ratings . 11
4.1 Rated voltage (U ) . 11
r
4.2 Rated insulation level . 11
4.3 Rated frequency (f ) . 11
r
4.4 Rated normal current and temperature rise . 11
4.5 Rated short-time withstand current (I ) . 12
k
4.6 Rated peak withstand current (I ) . 12
p
4.7 Rated duration of short circuit (t ) . 12
k
4.8 Rated supply voltage of closing and opening devices and of auxiliary and
control circuits (U ) . 12
a
4.9 Rated supply frequency of closing and opening devices and of auxiliary
circuits . 12
4.10 Rated pressure of compressed gas supply for controlled pressure systems . 13
4.11 Rated filling levels for insulation and/or operation . 13
5 Design and construction . 13
5.1 Requirements for liquids in GIL . 13
5.2 Requirements for gases in GIL . 13
5.3 Earthing . 13
5.4 Auxiliary and control equipment . 14
5.5 Dependent power operation . 14
5.6 Stored energy operation . 14
5.7 Independent manual or power operation (independent unlatched operation) . 14
5.8 Operation of releases . 14
5.9 Low- and high-pressure interlocking and monitoring devices . 14
5.10 Nameplates . 15
5.11 Interlocking devices . 15
5.12 Position indication. 16
5.13 Degree of protection provided by enclosures . 16
5.14 Creepage distances for outdoor insulators . 16
5.15 Gas and vacuum tightness . 16
5.16 Liquid tightness . 17
5.17 Fire hazard (flammability) . 17
5.18 Electromagnetic compatibility (EMC) . 17
5.19 X-ray emission . 17
5.20 Corrosion . 17
5.101 Internal fault . 18
5.102 Enclosures . 19

62271-204  IEC:2011 – 3 –
5.103 Partitions and partitioning . 20
5.104 Sections of a GIL system . 21
5.105 Pressure relief . 21
5.106 Compensation of thermal expansion . 22
5.107 External vibration . 22
5.108 Supporting structures for non-buried GIL . 22
6 Type tests . 23
6.1 General . 23
6.2 Dielectric tests . 24
6.3 Radio interference voltage (r.i.v.) test . 26
6.4 Measurement of the resistance of circuits . 26
6.5 Temperature-rise tests. 26
6.6 Short-time withstand current and peak withstand current tests. 26
6.7 Verification of the protection . 27
6.8 Tightness tests . 27
6.9 Electromagnetic compatibility tests (EMC) . 28
6.10 Additional test on auxiliary and control circuits . 28
6.11 X-radiation test procedure for vacuum interrupters . 28
6.101 Proof tests for enclosures . 28
6.102 Destructive pressure tests . 28
6.103 Anti-corrosion tests for buried installation . 28
6.104 Special mechanical test on sliding contacts . 29
6.105 Test under conditions of arcing due to internal fault . 30
6.106 Weatherproofing test . 31
7 Routine tests . 31
7.1 Dielectric tests on the main circuits . 31
7.2 Dielectric tests on auxiliary and control circuits . 31
7.3 Measurement of the resistance of the main circuit . 31
7.4 Tightness test . 31
7.5 Design and visual checks. 31
7.101 Partial discharge measurement . 31
7.102 Pressure tests of factory made enclosures . 32
8 Guide to the selection of GIL . 32
8.101 Short time overload capability . 32
8.102 Forced cooling . 32
9 Information to be given with enquiries, tenders and orders . 32
9.101 Information with enquiries and orders . 32
9.102 Information with tenders and contract documentation . 34
10 Transport, storage, installation, operation and maintenance . 35
10.1 Conditions during transport, storage and installation . 35
10.2 Installation . 35
10.3 Operation . 36
10.4 Maintenance . 40
11 Safety . 40
11.1 Precautions by manufacturers . 41
11.2 Precautions by users . 41
11.3 Electrical aspects . 41

– 4 – 62271-204  IEC:2011
11.4 Mechanical aspects . 41
11.5 Thermal aspects . 41
11.101 Maintenance aspects . 41
12 Influence of the product on the environment . 42
Annex A (informative) Estimation of continuous current . 43
Annex B (informative) Earthing . 48
Annex C (normative) Long-term testing of buried installations . 52
Bibliography . 54

Figure B.1 – Example of earthing system together with active anti-corrosion system in
the case of solid bonding of the enclosure at both ends . 51

Table 1 – Second characteristic numeral of IP coding . 16

62271-204  IEC:2011 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 204: Rigid gas-insulated transmission lines
for rated voltage above 52 kV
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) 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.
International Standard IEC 62271-204 has been prepared by subcommittee 17C: High-voltage
switchgear and controlgear assemblies, of IEC technical committee 17: Switchgear and con-
trolgear.
This standard cancels and replaces IEC/TS 61640:1998. It is a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• update to be in line with IEC 62271-1:2007 and 62271-203 and alignment of the voltage
ratings and the test voltages;
• addition of new information for gas tightness and corrosion protection.

– 6 – 62271-204  IEC:2011
The text of this standard is based on the following documents:
FDIS Report on voting
17C/510/FDIS 17C/520/RVD
Full information on the voting for the approval of this standard 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.
This International Standard should be read in conjunction with IEC 62271-1:2007, to which it
refers and which is applicable unless otherwise specified. In order to simplify the indication of
corresponding requirements, the same numbering of clauses and subclauses is used as in
IEC 62271-1. Amendments to these clauses and subclauses are given under the same
numbering, whilst additional subclauses, are numbered from 101. It should also be read in
conjunction with IEC 62271-203.
A list of all parts of the IEC 62271 series can be found, under the general title High-voltage
switchgear and controlgear, on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
stability 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.
___________
To be published.
62271-204  IEC:2011 – 7 –
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 204: Rigid gas-insulated transmission lines
for rated voltage above 52 kV
1 General
1.1 Scope
This part of IEC 62271 applies to rigid HV gas-insulated transmission lines (GIL) in which the
insulation is obtained, at least partly, by a non-corrosive insulating gas, other than air at atmos-
pheric pressure, for alternating current of rated voltages above 52 kV, and for service
frequencies up to and including 60 Hz.
It is intended that this international standard be used where the provisions of IEC 62271-203 do
not cover the application of GIL (see NOTE 3).
At each end of the HV gas-insulated transmission line, a specific element may be used for the
connection between the HV gas-insulated transmission line and other equipment like bushings,
power transformers or reactors, cable boxes, metal-enclosed surge arresters, voltage
transformers or GIS, covered by their own specification.
Unless otherwise specified, the HV gas-insulated transmission line is designed to be used
under normal service conditions.
NOTE 1 In this international standard, the term "HV gas-insulated transmission line" is abbreviated to "GIL".
NOTE 2 In this international standard, the word "gas" means gas or gas mixture, as defined by the manufacturer.
NOTE 3 Examples of GIL applications are given:
– where all or part of the HV gas-insulated transmission line is directly buried; or
– where the HV gas-insulated transmission line is located, wholly or partly, in an area accessible to
public; or
– where the HV gas-insulated transmission line is long and the typical gas compartment length exceeds the
common practice of GIS technology.
1.2 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 60050-151, International Electrotechnical Vocabulary (IEV) – Part 151: Electrical and
magnetic devices
IEC 60050-441:1984, International Electrotechnical Vocabulary (IEV) – Chapter 441:
Switchgear, controlgear and fuses
IEC 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60229:2007, Electric cables – Tests on extruded oversheaths with a special protective
function
– 8 – 62271-204  IEC:2011
IEC 60270, High-voltage test techniques – Partial discharge measurements
IEC 60287-3-1:1995, Electric cables – Calculation of the current rating – Part 3-1: Sections on
operating conditions – Reference operating conditions and selection of cable type
IEC 60376, Specification of technical grade sulfur hexafluoride (SF ) for use in electrical
equipment
) taken from
IEC 60480, Guidelines for the checking and treatment of sulfur hexafluoride (SF
electrical equipment and specification or its re-use
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 62271-1:2007, High-voltage switchgear and controlgear – Part 1: Common specifications
IEC 62271-203:2011, High-voltage switchgear and controlgear – Part 203:Gas-insulated metal-
enclosed switchgear for rated voltages above 52 kV
IEC 62271-303, High-voltage switchgear and controlgear – Part 303:Use and handling of
sulphur hexafluoride (SF )
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
2 Normal and special service conditions
Clause 2 of IEC 62271-1 is applicable with the following addition:
At any altitude the dielectric characteristics of the internal insulation are identical with those
measured at sea-level. For this insulation, therefore, no requirements concerning the altitude
are applicable.
The normal service conditions which apply to a GIL depending on the installation conditions are
given in 2.101, 2.102 and 2.103. When more than one of these installation conditions apply, the
relevant subclause shall apply to each section of the GIL.
2.101 Installation in open air
For determining the ratings of GIL for open air installation, the normal service conditions of
IEC 62271-1 shall apply. Typical rating conditions are also valid for open trenches.
If the actual service conditions differ from the normal service conditions, the ratings shall be
adapted accordingly.
Unless otherwise specified by the user, the special service conditions given in the IEC 62271-1
shall apply.
___________
To be published.
62271-204  IEC:2011 – 9 –
2.102 Buried installation
Typical values for thermal resistivity and soil temperature are:
– 1,2 K · m/W, and 20 °C in summer;
– 0,85 K · m/W, and 10 °C in winter.
For guidance, values given in IEC 60287-3-1 may be considered.
NOTE 1 For long distance transmission lines (several kilometres) site measurement of soil resistivity should also
be considered.
NOTE 2 The use of controlled backfill with a given soil thermal resistivity may also be considered.
NOTE 3 A risk of thermal runaway exists if the soil surrounding the buried GIL becomes dry. In order not to dry out
the soil, a maximum service temperature of the enclosure in the range of 50 °C to 60 °C is generally considered
acceptable.
The depth of laying shall be agreed between manufacturer and user. The determination of
depth of laying shall take into account thermo mechanical stresses, safety requirements and
local regulations.
2.103 Installation in tunnel, shaft or similar situation
Forced cooling is an adequate method and used in case of tunnel, shaft or similar installations.
In the case of long vertical shafts and inclinated tunnels or sections thereof, attention shall be
paid to thermal and density gradients, especially if a gas mixture is used.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-441,
IEC 60050-151, IEC 62271-1, as well as the following apply.
3.101
area accessible to public
access not restricted to authorized personnel
NOTE A GIL installed above ground and outside a substation is considered to be "installed in an area accessible
to public".
3.102
gas-insulated transmission lines
GIL
metal-enclosed lines in which the insulation is obtained, at least partly, by an insulating gas
other than air at atmospheric pressure, with the external enclosure intended to be earthed
3.103
GIL enclosure
a part of gas-insulated line retaining the insulating gas under the prescribed conditions
necessary to maintain safely the rated insulation level, protecting the equipment against
external influences and providing a high degree of protection to personnel
3.104
compartment
part of gas-insulated line, totally enclosed except for openings necessary for interconnection
and control
– 10 – 62271-204  IEC:2011
3.105
partition
part of gas-insulated line separating one compartment from other compartments
3.106
main circuit
all conductive parts of gas-insulated line included in a circuit which is intended to transmit
electrical energy
[IEC 60050-441:1984, 441-13-02, modified]
3.107
ambient air temperature (of gas-insulated line)
temperature, determined under prescribed conditions, of the air surrounding the external GIL
enclosure of gas-insulated line in case of installation in open air, open trenches or tunnels
[IEC 60050-441:1984, 441-11-13, modified]
3.108
design temperature (of the enclosure)
highest temperature which can be reached by the enclosure under service conditions
3.109
design pressure (of the enclosure)
relative pressure used to determine the design of the enclosure
NOTE It is at least equal to the maximum pressure in the enclosure at the highest temperature that the gas used
for isolation can reach under specified maximum service conditions.
3.110
design pressure (of the partition)
pressure used to determine the design of the partition
3.111
disconnecting unit
unit to separate gas compartments mainly for site testing or maintenance
3.112
disruptive discharge
phenomena associated with the failure of insulation under electric stress, in which the dis-
charge completely bridges the insulation under test, reducing the voltage between the
electrodes to zero or almost zero
NOTE 1 The term applies to discharges in solid, liquid and gaseous dielectrics and to combinations of these.
NOTE 2 A disruptive discharge in a solid dielectric produces permanent loss of dielectric strength (non-self-
restoring insulation); in a liquid or gaseous dielectric, the loss may be only temporary (self-restoring insulation).
NOTE 3 The term "sparkover" is used when a disruptive discharge occurs in a gaseous or liquid dielectric. The
term "flashover" is used when a disruptive discharge occurs over the surface of a solid dielectric in a gaseous or
liquid medium. The term "puncture" is used when a disruptive discharge occurs through a solid dielectric.
3.113
GIL section
a GIL section is defined by operational or other requirements such as maximum length for
dielectric testing or installation sequence
NOTE 1 It may consist of one or more compartments.

62271-204  IEC:2011 – 11 –
NOTE 2 Sections may be segregated by disconnecting units.
4 Ratings
Clause 4 of IEC 62271-1 is not applicable, except as follows.
The rating of a GIL consists of the following:
a) rated voltage (U ) and number of phases;
r
b) rated insulation level;
c) rated frequency (f );
r
d) rated normal current (I ) (for main circuits);
r
e) rated short-time withstand current (I ) (for main and earthing circuits);
k
f) rated peak withstand current (I ) (for main and earthing circuits);
p
g) rated duration of short-circuit (t );
k
h) rated values of the components forming part of a GIL, including auxiliary equipment;
i) rated filling pressure of insulating gas.
)
4.1 Rated voltage (U
r
Subclause 4.1 of IEC 62271-203 is applicable.
4.2 Rated insulation level
Subclause 4.2 of IEC 62271-1 is applicable with the following addition:
Rated insulation levels shall be chosen from IEC 62271-203 on the basis of insulation
coordination study for the specific installation in order to consider parameters like
overvoltages, voltage reflections, etc. Specific insulation coordination studies are
recommended for each installation.
Although internal arcing faults can largely be avoided by the choice of a suitable insulation
level, measures to limit external over-voltages at each end of the installation (e.g. surge
arresters) should be considered.
4.3 Rated frequency (f )
r
Subclause 4.3 of IEC 62271-1 is applicable.
4.4 Rated normal current and temperature rise
4.4.1 Rated normal current (I )
r
Subclause 4.4.1 of IEC 62271-1 is applicable with the following addition:
The rated normal current is defined for a single, three-phase circuit installed above ground with
an ambient air temperature at 40 °C. For other installation conditions, see Annex A.
4.4.2 Temperature rise
Subclause 4.4.2 of IEC 62271-1 is applicable with the following addition:
The temperature of the enclosure shall not exceed the maximum allowable temperature of the
anti-corrosion coating if applicable.

– 12 – 62271-204  IEC:2011
The temperature rise of components contained in the GIL which are subject to standards not
covered by the scope of IEC 62271-1 shall not exceed the temperature-rise limits permitted in
the relevant standard for those components.
For open air, tunnel and shaft installations, the maximum temperature of the enclosure shall
not exceed 80 °C. Parts normally touched during operation not to exceed 70 °C. Reference is
made to Clause 11 of this standard.
For direct buried installation, the maximum temperature of the enclosure shall be limited to
minimise soil drying. A temperature in the 50 °C and 60 °C range is generally considered
applicable.
4.4.3 Particular points of Table 3
Subclause 4.4.3 of IEC 62271-1 is applicable.
4.4.101 Particular requirements for temperature rise
Where a non-oxidizing gas is used as the dielectric, the limits of the temperature and
temperature rise shall be as specified for SF in Table 3 of IEC 62271-1.
Where compressed air is used as the dielectric, the limits of the temperature and temperature
rise shall be as specified for air in Table 3 of IEC 62271-1.
Where an oxidizing gas (other than air) is used as the dielectric, lower limits of temperature
and temperature rise shall be agreed between manufacturer and user.
4.5 Rated short-time withstand current (I )
k
Subclause 4.5 of IEC 62271-1 is applicable, with the following addition.
In selecting a rated short-time withstand current for an installation, or part of an installation,
consideration may be given to the fact that the maximum fault current in a circuit reduces as
the distance from the substation increases.
4.6 Rated peak withstand current (I )
p
Subclause 4.6 of IEC 62271-1 is applicable.
4.7 Rated duration of short circuit (t )
k
Subclause 4.7 of IEC 62271-1 is applicable.
4.8 Rated supply voltage of closing and opening devices and of auxiliary and control
circuits (U )
a
Subclause 4.8 of IEC 62271-1 is applicable.
4.9 Rated supply frequency of closing and opening devices and of auxiliary circuits
Subclause 4.9 of IEC 62271-1 is applicable with the following addition:
The rated supply frequency of auxiliary circuits is the frequency at which the conditions of
operation and temperature rise of these devices and circuits are determined.

62271-204  IEC:2011 – 13 –
4.10 Rated pressure of compressed gas supply for controlled pressure systems
Subclause 4.10 of IEC 62271-1 is not applicable.
4.11 Rated filling levels for insulation and/or operation
Subclause 4.11 of IEC 62271-1 is applicable.
5 Design and construction
Clause 5 of IEC 62271-1 is not applicable, except as follows.
Any component which requires routine preventive maintenance or diagnostic testing shall be
easily accessible.
GIL shall be designed so that normal service, inspection and maintenance operations can be
carried out safely, including the checking of phase sequence after erection and extension.
The equipment shall be designed such that the mechanical stress caused by all relevant loads,
for example thermal expansion, agreed permitted movement of foundations, external vibration,
earthquakes, soil loading, wind and ice do not impair the assigned performance of the
equipment.
All components of the same rating and construction which may need to be replaced shall be
interchangeable.
5.1 Requirements for liquids in GIL
Clause 5.1 of IEC 62271-1 is not applicable.
5.2 Requirements for gases in GIL
Subclause 5.2 of IEC 62271-1 is applicable.
In case a gas mixture is used, the manufacturer should provide information about the gas
characteristics such as dielectric strength, mixing ratio, process of mixing and filling pressure.
NOTE See references [6], [7] and [8] in the Bibliography.
5.3 Earthing
Subclause 5.3 of IEC 62271-1 is applicable, except as follows.
5.3.101 Earthing of main circuits
To ensure safety during maintenance work all parts of the main circuits to which access is
required or provided shall be capable of being earthed. In addition, it shall be possible, after
the opening of the enclosure, to connect earth electrodes to the conductor for the duration of
the work.
Earthing may be made by
a) earthing switches with a making current capacity equal to the rated peak withstand current,
if there is no certainty that the circuit connected is not live;
b) earthing switches without a making current capacity or with a making capacity lower than
the rated peak withstand current, if there is certainty that the circuit connected is not live;

– 14 – 62271-204  IEC:2011
c) removable earthing devices, only by agreement between manufacturer and user.
Each part being capable of being disconnected shall be capable of being earthed.
Consideration shall be given to the ability of the first operated earthing device to dissipate the
maximum level of trapped charge on the isolated circuit.
Where the earthing switches form part of the plant connected to the transmission line, the user
shall ensure that they comply with the above items a) to c).
5.3.102 Earthing of the enclosure
The enclosures shall be capable of being connected to earth. All metal parts intended to be
earthed, which do not belong to a main or an auxiliary circuit, shall be connected to earth. For
the interconnection of enclosures, frames, etc., fastening (e.g. bolting or welding) is generally
acceptable for providing electrical continuity. If the fastening is done by bolting, provisions shall
be given in order that a proper electrical contact is provided. If not, the mechanical joint shall
be by-passed by a proper electrical connection such as copper or aluminium leads of proper
cross section.
The continuity of the earthing circuits shall be ensured taking into account the thermal and
electrical stresses caused by the current they may have to carry.
It is envisaged that most GIL installation will be solidly bonded and earthed at both ends. The
particular design has an influence on heat dissipation, standing voltages and the external
magnetic field. These are discussed in Annex B.
The design of the earthing of the enclosure shall be compatible with the measures for corrosion
protection when the GIL is buried.
5.4 Auxiliary and control equipment
Subclause 5.4 of IEC 62271-1 is applicable.
5.5 Dependent power operation
Subclause 5.5 of IEC 62271-1 is not applicable.
5.6 Stored energy operation
Subclause 5.6 of IEC 62271-1 is not applicable.
5.7 Independent manual or power operation (independent unlatched operation)
Subclause 5.7 of IEC 62271-1 is not applicable.
5.8 Operation of releases
Subclause 5.8 of IEC 62271-1 is not
...