IEC 62271-204:2022
(Main)High-voltage switchgear and controlgear - Part 204: Rigid gas-insulated transmission lines for rated voltage above 52 kV
High-voltage switchgear and controlgear - Part 204: Rigid gas-insulated transmission lines for rated voltage above 52 kV
IEC 62271-204:2022 applies to rigid HV gas‑insulated transmission lines (GIL) in which the insulation is obtained, at least partly, by an insulating gas or gas mixture other than air at atmospheric pressure, for alternating current of rated voltages above 52 kV, and for service frequencies up to and including 60 Hz. This second edition cancels and replaces the first edition published in 2011. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- update to be in line with IEC 62271-1:2017 and alignment of the voltage ratings and the test voltages.
- addition of new information for welds on pressurized parts and gas tightness.
Appareillage à haute tension - Partie 204: Lignes de transport rigides à isolation gazeuse de tension assignée supérieure à 52 kV
L’IEC 62271-204:2022 est applicable aux lignes de transport rigides haute tension à isolation gazeuse (LIG) dont l’isolation est réalisée, au moins partiellement, par un gaz isolant ou un mélange gazeux autre que l’air à la pression atmosphérique, pour un courant alternatif de tension assignée supérieure à 52 kV, pour des fréquences de service inférieures ou égales à 60 Hz. Cette deuxième édition annule et remplace la première édition parue en 2011. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- mise à jour par rapport à l’IEC 62271-1:2017 et alignement des caractéristiques assignées de tension et des tensions d’essai;
- ajout de nouvelles informations relatives aux soudures sur les parties sous pression et à l’étanchéité au gaz.
General Information
Relations
Standards Content (Sample)
IEC 62271-204 EXV ®
Edition 2.0 2022-09
EXTENDED VERSION
INTERNATIONAL
STANDARD
colour
inside
This extended version of IEC 62271-204:2022 includes the content of the references made to
IEC 62271-1:2017+AMD1:2021 CSV and IEC 62271-203:2022
High-voltage switchgear and controlgear –
Part 204: Rigid gas-insulated transmission lines for rated voltage above 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.: +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 - 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. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
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 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary
(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.
IEC 62271-204 EXV ®
Edition 2.0 2022-09
EXTENDED VERSION
INTERNATIONAL
STANDARD
colour
inside
This extended version of IEC 62271-204:2022 includes the content of the references made to
IEC 62271-1:2017+AMD1:2021 CSV and IEC 62271-203:2022
High-voltage switchgear and controlgear –
Part 204: Rigid gas-insulated transmission lines for rated voltage above 52 kV
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.130.10 ISBN 978-2-8322-5677-0
IEC 62271-1:2017/ISH1:2021 – 1 –
© IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
IEC 62271-1
Edition 2.0 2017-07
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 1: Common specifications for alternating
current switchgear and controlgear
INT ERPRET AT ION SHEET 1
This interpretation sheet has been prepared by IEC technical committee 17: High-voltage
switchgear and controlgear.
The text of this interpretation sheet is based on the following documents:
DISH Report on voting
17/1090/DISH 17/1095/RVDISH
Full information on the voting for the approval of this interpretation sheet can be found in the
report on voting indicated in the above table.
___________
Interpretation of 4.2.2 of IEC 62271-1:2017 regarding the altitude correction factor
Subclause 4.2.2 of IEC 62271-1:2017 contains two references for calculation of the required
insulation withstand level at altitudes higher than 1 000 m, IEC 60071-2:1996 and
IEC TR 62271-306. The two references are in conflict, as the altitude correction factor
according to IEC 60071-2:1996 starts at sea level and that of IEC TR 62271-306 starts at an
altitude of 1 000 m. This results in different altitude correction factors.
As already stated in 5.3 of IEC 62271-1:2017, the rated insulation levels refer to normal
service conditions. Altitudes up to 1 000 m above sea level are covered and need no altitude
correction.
For altitudes higher than 1 000 m the equation provided in 4.5.1.1 b) of
IEC TR 62271-306:2012 and in H.3.4 of IEC 60071-2:2018 shall be used, i.e.
H−1 000
m( )
8 150
k =e
alt
ICS 29.130.10; 29.130.99
IEC 62271-1:2017-07/ISH1:2021-05(en-fr)
– 2 – IEC 62271-1:2017/ISH1:2021
© IEC 2021
where
k is the altitude correction factor;
alt
H is the altitude in m above sea level;
m is an exponent.
Conservative values for the exponent m are provided in Table 4 of IEC TR 62271-306:2012.
For further details about the exponent m, see H.4 of IEC 60071-2:2018.
– 2 – IEC 62271-204:2022 EXV © IEC 2022
CONTENTS
FOREWORD . 10
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 15
3.1 General terms and definitions . 15
3.2 Assemblies of switchgear and controlgear . 18
3.3 Parts of assemblies . 18
3.4 Switching devices . 19
3.5 Parts of switchgear and controlgear . 19
3.6 Operational characteristics of switchgear and controlgear . 23
3.7 Characteristic quantities . 26
3.8 Index of definitions . 27
4 Normal and special service conditions . 31
4.1 Normal service conditions . 31
4.1.1 General . 31
4.1.2 Indoor switchgear and controlgear . 31
4.1.3 Outdoor switchgear and controlgear . 31
4.2 Special service conditions . 32
4.2.1 General . 32
4.2.2 Altitude . 32
4.2.3 Exposure to pollution . 32
4.2.4 Temperature and humidity . 33
4.2.5 Exposure to abnormal vibrations, shock or tilting . 33
4.2.6 Wind speed . 33
4.2.7 Other parameters . 33
4.101 Installation in open air. 33
4.102 Buried installation . 33
4.103 Installation in tunnel, shaft or similar situation . 34
5 Ratings . 34
5.1 General . 34
5.2 Rated voltage (U ) . 34
r
5.2.1 General . 34
5.2.2 Range I for rated voltages of 245 kV and below . 35
5.2.3 Range II for rated voltages above 245 kV . 35
5.3 Rated insulation level (U , U , U ) . 35
d p s
5.4 Rated frequency (f ) . 39
r
5.5 Rated continuous current (I ) . 39
r
5.6 Rated short-time withstand current (I ) . 40
k
5.7 Rated peak withstand current (I ) . 40
p
5.8 Rated duration of short-circuit (t ) . 40
k
5.9 Rated supply voltage of auxiliary and control circuits (U ) . 41
a
5.9.1 General . 41
5.9.2 Rated supply voltage (U ). 41
a
5.10 Rated supply frequency of auxiliary and control circuits . 41
5.11 Rated pressure of compressed gas supply for controlled pressure systems . 41
6 Design and construction . 42
6.1 Requirements for liquids in GIL . 42
6.2 Requirements for gases in GIL . 42
6.3 Earthing . 42
6.3.101 Earthing of the main circuits . 43
6.3.102 Earthing of the enclosure . 43
6.4 Auxiliary and control equipment . 43
6.4.1 General . 43
6.4.2 Protection against electric shock . 44
6.4.3 Components installed in enclosures . 45
6.5 Dependent power operation . 47
6.6 Stored energy operation. 47
6.7 Independent manual or power operation (independent unlatched operation) . 48
6.8 Manually operated actuators . 48
6.9 Operation of releases . 48
6.10 Pressure/level indication . 48
6.10.1 Gas pressure. 48
6.10.2 Liquid level . 48
6.11 Nameplates . 48
6.11.1 General . 48
6.11.2 Application . 49
6.12 Locking devices . 49
6.13 Position indication . 49
6.14 Degree of protection provided by enclosures . 49
6.14.1 General . 49
6.14.2 Protection of persons against access to hazardous parts and protection of
the equipment against ingress of solid foreign objects (IP coding) . 49
6.14.3 Protection against ingress of water (IP coding) . 50
6.14.4 Protection against mechanical impact under normal service conditions
(IK coding) . 50
6.15 Creepage distances for outdoor insulators . 50
6.16 Gas and vacuum tightness . 50
6.16.1 General . 50
6.16.2 Controlled pressure systems for gas . 50
6.16.3 Closed pressure systems for gas . 51
6.16.4 Sealed pressure systems . 51
6.16.5 Internal partitions . 52
6.17 Tightness of liquid systems . 52
6.18 Fire hazard (flammability) . 52
6.19 Electromagnetic compatibility (EMC) . 52
6.20 X-ray emission . 52
6.21 Corrosion . 52
6.21.101 Corrosion protection for buried installations . 52
6.21.102 Corrosion protection for not buried installations . 52
6.22 Filling levels for insulation, switching and/or operation . 52
6.101 Minimizing of internal fault effects . 53
– 4 – IEC 62271-204:2022 EXV © IEC 2022
6.101.1 General . 53
6.101.2 External effects of the arc . 53
6.101.3 Internal fault location . 53
6.102 Enclosures . 54
6.102.1 General . 54
6.102.2 Design of enclosures . 54
6.103 Partitions and partitioning . 55
6.104 Sections of a GIL system . 55
6.105 Pressure relief . 56
6.105.1 General . 56
6.105.2 Limitation of maximum filling pressure . 56
6.105.3 Pressure relief devices to limit pressure rise in the case of an internal fault . 56
6.106 Compensation of thermal expansion . 56
6.107 External vibrations . 57
6.108 Supporting structures for non-buried GIL . 57
6.108.1 General . 57
6.108.2 Conditions of the design . 57
6.108.3 Types of supporting structures . 57
7 Type tests . 58
7.1 General . 58
7.1.1 Basics . 58
7.1.2 Information for identification of test objects . 58
7.1.3 Information to be included in type-test reports . 58
7.1.101 Mandatory type tests . 59
7.1.102 Special type tests . 59
7.2 Dielectric tests . 60
7.2.1 General . 60
7.2.2 Ambient air conditions during tests . 60
7.2.3 Wet test procedure . 60
7.2.4 Arrangement of the equipment . 60
7.2.5 Criteria to pass the test. 60
7.2.6 Application of test voltage and test conditions . 61
7.2.7 Test of switchgear and controlgear of U ≤ 245 kV . 61
r
7.2.8 Test of switchgear and controlgear of U > 245 kV . 61
r
7.2.9 Artificial pollution tests for outdoor insulators. 62
7.2.10 Partial discharge tests . 62
7.2.11 Dielectric tests on auxiliary and control circuits . 63
7.2.12 Voltage test as condition check . 63
7.3 Radio interference voltage (RIV) test . 63
7.4 Measurement of the resistance of circuits . 63
7.4.1 Measurement of the resistance of auxiliary contacts class 1 and class 2 . 64
7.4.2 Measurement of the resistance of auxiliary contacts class 3 . 64
7.4.3 Electrical continuity of earthed metallic parts test . 64
7.4.4 Resistance measurement of contacts and connections in the main circuit
as a condition check . 64
7.5 Continuous current test . 65
7.5.1 Condition of the test object . 65
7.5.2 Arrangement of the equipment . 65
7.5.3 Test current and duration . 66
7.5.4 Temperature measurement during test . 67
7.5.5 Resistance of the main circuit . 68
7.5.6 Criteria to pass test . 68
7.6 Short-time withstand current and peak withstand current tests . 73
7.6.1 General . 73
7.6.2 Arrangements of the GIL and of the test circuit . 73
7.6.3 Test current and duration . 73
7.6.4 Conditions of the GIL after test . 74
7.7 Verification of the protection . 74
7.7.1 Verification of the IP coding . 74
7.7.2 Verification of the IK coding . 75
7.8 Tightness tests . 75
7.8.1 General . 75
7.8.2 Controlled pressure systems for gas . 76
7.8.3 Closed pressure systems for gas . 77
7.8.4 Sealed pressure systems . 77
7.8.5 Liquid tightness tests . 77
7.9 Electromagnetic compatibility tests (EMC) . 78
7.10 Additional test on auxiliary and control circuits. 78
7.11 X-radiation test procedure for vacuum interrupters . 78
7.101 Proof tests for enclosures . 78
7.101.1 General . 78
7.101.2 Destructive pressure tests . 78
7.101.3 Non-destructive pressure test . 79
7.102 Pressure test on partitions . 80
7.103 Passive corrosion protection tests for buried installation . 80
7.103.1 Passive corrosion protection . 80
7.103.2 Electrical testing . 80
7.103.3 Mechanical testing . 80
7.103.4 Thermal testing . 80
7.104 Special mechanical test on sliding contacts . 81
7.105 Test under conditions of arcing due to internal fault . 81
7.106 Weatherproofing test . 82
8 Routine tests . 82
8.1 General . 82
8.2 Dielectric test on the main circuit. 83
8.3 Tests on auxiliary and control circuits . 83
8.3.1 Inspection of auxiliary and control circuits, and verification of conformity to
the circuit diagrams and wiring diagrams . 83
8.3.2 Functional tests . 84
8.3.3 Verification of protection against electrical shock . 84
8.3.4 Dielectric tests . 84
8.4 Measurement of the resistance of the main circuit. 84
8.5 Tightness test . 84
8.5.1 General . 84
8.5.2 Controlled pressure systems for gas . 84
8.5.3 Closed pressure systems for gas . 85
8.5.4 Sealed pressure systems . 85
– 6 – IEC 62271-204:2022 EXV © IEC 2022
8.5.5 Liquid tightness tests . 85
8.6 Design and visual checks . 85
8.101 Partial discharge measurement . 85
8.102 Pressure tests of factory made enclosures . 85
9 Guide to the selection of GIL (informative) . 86
9.1 General . 86
9.2 Selection of rated values. 86
9.3 Cable-interface considerations . 86
9.4 Continuous or temporary overload due to changed service conditions . 86
9.5 Environmental aspects . 86
9.5.1 Service conditions . 86
9.5.2 Clearances affected by service conditions . 87
9.5.3 High humidity . 87
9.5.4 Solar radiation . 87
9.101 Short time overload capability . 87
9.102 Forced cooling . 87
10 Information to be given with enquiries, tenders and orders (informative) . 87
10.101 Information with enquiries and orders . 87
10.101.1 General . 87
10.101.2 Particulars of the system . 88
10.101.3 Environmental conditions . 88
10.101.4 Service conditions . 88
10.101.5 Particulars of the installation . 88
10.101.6 Particulars of the auxiliary devices . 88
10.101.7 Specific conditions. 89
10.102 Information with tenders and contract documentation . 89
10.102.1 General . 89
10.102.2 Rated values and characteristics . 89
10.102.3 Further particulars of the transmission line and its components . 89
10.102.4 Type test certificate or reports . 89
10.102.5 Particulars of the auxiliary devices . 89
10.102.6 List of recommended essential spare parts . 89
11 Transport, storage, installation, operating instructions and maintenance . 89
11.1 General . 89
11.2 Conditions during transport, storage and installation . 90
11.3 Installation . 90
11.3.1 General . 90
11.3.2 Unpacking and lifting . 91
11.3.3 Assembly . 91
11.3.4 Mounting . 91
11.3.5 Connections . 91
11.3.6 Information about gas and gas mixtures for controlled and closed
pressure systems . 91
11.3.7 Final installation inspection . 92
11.3.8 Basic input data by the user . 92
11.3.9 Basic input data by the manufacturer . 93
11.3.101 Constructional features . 93
11.4 Operating instructions . 93
11.4.101 Voltage test on the main circuits . 94
11.4.102 Measurement of gas conditions . 95
11.4.103 Measurement of the resistance of the main circuit . 95
11.4.104 Tests on enclosures welded on site . 96
11.4.105 Periodic testing of the enclosure . 96
11.4.106 Checks and verifications . 96
11.4.107 Tests on corrosion protection for directly buried GIL . 96
11.5 Maintenance . 97
11.5.1 General . 97
11.5.2 Information about fluids and gas to be included in maintenance manual . 97
11.5.3 Recommendations for the manufacturer . 97
11.5.4 Recommendations for the user. 98
11.5.5 Failure report . 99
11.5.101 Maintenance of GIL . 100
11.5.102 Gas handling . 100
12 Safety . 101
12.1 General . 101
12.2 Precautions by manufacturers . 101
12.3 Precautions by users . 102
12.101 Mechanical aspects . 102
12.102 Thermal aspects . 103
12.103 Maintenance aspects . 103
13 Influence of the product on the environment . 103
Annex A (normative) Identification of test objects . 104
A.1 General . 104
A.2 Data . 104
A.3 Drawings . 104
Annex B (informative) Determination of the equivalent RMS value of a short-time current
during a short-circuit of a given duration . 106
Annex C (normative) Method for the weatherproofing test for outdoor switchgear and
controlgear . 107
Annex D (informative) References for auxiliary and control circuit components . 110
Annex E (normative) Tolerances on test quantities during tests . 112
Annex F (informative) Information and technical requirements to be given with enquiries,
tenders and orders . 115
F.1 General . 115
F.2 Normal and special service conditions (refer to Clause 4) . 115
F.3 Ratings (refer to Clause 5) . 116
F.4 Design and construction (refer to Clause 6) . 116
F.5 System information . 117
F.6 Documentation for enquiries and tenders . 117
Annex G (informative) List of symbols . 118
Annex H (informative) Electromagnetic compatibility on site . 120
Annex I (informative) List of notes concerning certain countries . 121
Annex J (informative) Extension of validity of type tests . 122
J.1 General . 122
– 8 – IEC 62271-204:2022 EXV © IEC 2022
J.2 Dielectric tests . 122
J.3 Short-time withstand current tests . 122
J.4 Continuous current test . 122
J.5 Electromagnetic immunity test on auxiliary and control circuits . 123
J.6 Environmental tests on auxiliary and control circuits . 123
Annex K (informative) Exposure to pollution . 124
K.1 General . 124
K.2 Pollution levels . 124
K.3 Minimum requirements for switchgear . 124
Annex A (informative) Estimation of continuous current . 126
A.1 General . 126
A.2 Symbols . 126
A.3 Reference values . 126
A.3.1 General . 126
A.3.2 General type test values . 127
A.3.3 AC resistances . 127
A.3.4 Dissipation . 127
A.3.5 Thermal resistances . 128
A.3.6 Thermal coefficient . 128
A.4 Estimation of current rating . 128
A.4.1 General . 128
A.4.2 Maximum temperature rise . 128
A.4.3 Heat input . 129
A.4.4 Thermal resistances . 129
A.4.5 Estimated maximum temperature rise . 129
A.4.6 Permissible temperature rises . 130
A.4.7 Estimated continuous current . 130
A.4.8 Informal documents . 130
Annex B (informative) Earthing . 131
B.1 General . 131
B.2 Safe limits on potential rise . 131
B.3 Enclosures . 131
B.4 Earth electrodes . 131
B.5 Conductors of earthing system . 131
B.6 Earth continuity . 132
B.7 Induced voltages . 132
B.8 Transient enclosure voltage . 132
B.9 Non-linear resistors . 132
B.10 Bonding and earthing . 133
B.10.1 General . 133
B.10.2 Cross-bonding . 133
B.11 Application to directly buried installations . 133
B.12 Informal documents . 134
Annex C (informative) Long-term testing of buried installations . 135
C.1 Assessment of long-term behaviour . 135
C.1.1 General . 135
C.1.2 Thermomechanical performance . 135
C.1.3 Corrosion protection of the enclosures . 135
C.2 Summary of long-term tests . 135
Annex D (normative) Requirements for welds on pressurized parts . 137
D.1 General . 137
D.2 Process and personal qualifications . 137
D.3 Non-destructive tests of welding .
...
IEC 62271-204 ®
Edition 2.0 2022-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
High-voltage switchgear and controlgear –
Part 204: Rigid gas-insulated transmission lines for rated voltage above 52 kV
IEC IEC 62271-204:2022-05 RLV(en)
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.: +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 - 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. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
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 22 300 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 19 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary
(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.
IEC 62271-204 ®
Edition 2.0 2022-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
High-voltage switchgear and controlgear –
Part 204: Rigid gas-insulated transmission lines for rated voltage above 52 kV
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.130.10 ISBN 978-2-8322-3805-9
– 2 – IEC 62271-204:2022 RLV © IEC 2022
CONTENTS
FOREWORD . 3
1 General .
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Normal and special service conditions . 8
5 Ratings . 9
6 Design and construction . 12
7 Type tests . 23
8 Routine tests . 31
9 Guide to the selection of GIL (informative) . 33
10 Information to be given with enquiries, tenders and orders (informative) . 33
11 Transport, storage, installation, operation operating instructions and maintenance . 36
12 Safety . 42
13 Influence of the product on the environment . 44
Annex A (informative) Estimation of continuous current . 45
Annex B (informative) Earthing . 50
Annex C (normative informative) Long-term testing of buried installations . 54
Annex D (normative) Requirements for welds on pressurized parts . 56
Bibliography . 58
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 . 53
Table 1 – Second characteristic numeral of IP coding . 16
Table D.1 – Quantity of NDTs . 56
Table D.2 – Acceptance criteria of imperfections . 57
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.
This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 62271-204:2011. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.
– 4 – IEC 62271-204:2022 RLV © IEC 2022
IEC 62271-204 has been prepared by subcommittee 17C: Assemblies, of IEC technical
committee 17: High-voltage switchgear and controlgear. It is an International Standard.
This second edition cancels and replaces the first edition published in 2011. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) update to be in line with IEC 62271-1:2017 and alignment of the voltage ratings and the test
voltages.
b) addition of new information for welds on pressurized parts and gas tightness.
The text of this document is based on the following documents:
Draft Report on voting
17C/840/FDIS 17C/846/RVD
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/standardsdev/publications.
This document is to be read in conjunction with IEC 62271-1:2017 and IEC 62271-203:2022, to
which it refers and which are 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 62271-1:2017 and IEC 62271-203:2022. Amendments to these clauses and
subclauses are given under the same numbering, whilst additional subclauses are numbered
from 101.
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 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,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 204: Rigid gas-insulated transmission lines
for rated voltage above 52 kV
1 General
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, an insulating gas or
gas mixture other than air at atmospheric pressure, for alternating current of rated voltages
above 52 kV, and for service frequencies up to and including 60 Hz.
This document is intended that this international standard be used applicable 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 is 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 document, the term "HV gas-insulated transmission line" is abbreviated to "GIL".
NOTE 2 In this document, the word "gas" means gas or gas mixture, as defined by the manufacturer.
NOTE 3 Examples of GIL applications:
– where all or part of the HV gas-insulated transmission line is directly buried;
– where the HV gas-insulated transmission line is located, wholly or partly, in an area accessible to public;
– where the HV gas-insulated transmission line is long (typically longer than 500 m) and the typical gas
compartment length exceeds the common practice of GIS technology.
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 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 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
– 6 – IEC 62271-204:2022 RLV © IEC 2022
IEC 60229:2007, Electric cables – Tests on extruded oversheaths with a special protective
function
IEC 60270, High-voltage test techniques – Partial discharge measurements
IEC 60287-3-1:19952017, Electric cables – Calculation of the current rating – Part 3-1: Sections
on Operating conditions – Reference operating conditions and selection of cable type Site
reference conditions
IEC 60376, Specification of technical grade sulfur hexafluoride (SF ) and complementary gases
to be used in its mixtures for use in electrical equipment
IEC 60480, Guidelines for the checking and treatment of sulfur hexafluoride (SF ) taken from
electrical equipment and specification or its re-use Specifications for the re-use of sulfur
hexafluoride (SF ) and its mixtures in electrical equipment
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60529:1989/AMD1:1999
IEC 60529:1989/AMD2:2013
IEC 62271-1:20072017, High-voltage switchgear and controlgear – Part 1: Common
specifications for alternating current switchgear and controlgear
IEC 62271-203:20112022, High-voltage switchgear and controlgear – Part 203: AC
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 )
IEC 62271-4:2013, High-voltage switchgear and controlgear – Part 4: Handling procedures for
sulphur hexafluoride (SF ) and its mixtures
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
ISO 9606 (all parts), Qualification test of welders – Fusion welding
ISO 9712, Non-destructive testing – Qualification and certification of NDT personnel
ISO 14732, Welding personnel – Qualification testing of welding operators and weld setters for
mechanized and automatic welding of metallic materials
ISO 15609 (all parts), Specification and qualification of welding procedures for metallic
materials – Welding procedure specification
ISO 15614 (all parts), Specification and qualification of welding procedures for metallic
materials – Welding procedure test
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-441,
IEC 60050-151, IEC 62271-1:2017 and the following apply.
___________
To be published.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.101
area accessible to public
access not restricted to authorized personnel
area accessible without restriction to any person
Note 1 to entry: A GIL installed above the 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
part of gas-insulated line GIL retaining the insulating gas under the prescribed required
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, GIL totally gastight enclosed except for openings necessary for
interconnection and control
3.105
partition
part of gas-insulated line separating one compartment from other compartments
gas tight support insulator of gas-insulated metal-enclosed switchgear separating two adjacent
compartments
3.106
main circuit
all the conductive parts of gas-insulated line GIL included in a circuit which is intended to
transmit electrical energy
[SOURCE: IEC 60050-441:1984, 441-13-02, modified – Replacement of “an assembly" by
“GIL".]
3.107
ambient air temperature (of gas-insulated line)
temperature, determined under prescribed required conditions, of the air surrounding the
external GIL enclosure of gas-insulated line in case of installation in open air, open trenches or
tunnels
[SOURCE: IEC 60050-441:1984, 441-11-13, modified – Replacement of “complete switching
device or fuse" by “external GIL enclosure in case of installation in open air, open trenches or
tunnels".]
3.108
design temperature (of the enclosure)
highest maximum temperature which can be reached by the on a GIL enclosure under service
conditions
– 8 – IEC 62271-204:2022 RLV © IEC 2022
3.109
design pressure (of the enclosure)
relative pressure used to determine the design of the enclosure
Note 1 to entry: It is at least equal to the maximum relative pressure in the enclosure at the highest temperature
that the gas used for isolation can reach under specified maximum service conditions design temperature of the
enclosure.
3.110
design pressure (of the partitions)
relative pressure used to determine the design of across the partition
Note 1 to entry: It is at least equal to the maximum differential pressure across the partition during maintenance
activities.
3.111
disconnecting unit
unit to separate gas compartments electrically isolate one side from another of the main circuit,
mainly for site testing or maintenance
3.112
disruptive discharge
phenomenon 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 to entry: The term applies to discharges in solid, liquid and gaseous dielectrics and to combinations of these.
Note 2 to entry: 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 can be only temporary (self-restoring insulation).
Note 3 to entry: 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 part of GIL which is defined by operational or other requirements such as
maximum length for dielectric testing or installation sequence
Note 1 to entry: A GIL can consist on the assembly of several GIL sections.
Note 1 2 to entry: It may can consist of one or more compartments.
Note 2 3 to entry: Sections may can be segregated by disconnecting units.
4 Normal and special service conditions
4.1 Normal service conditions
4.1.1 General
Subclause 4.1.1 of IEC 62271-1:2017 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 4.101, 4.102 and 4.103. When more than one of these installation conditions apply, the
relevant subclause shall apply to each section of the GIL.
4.1.2 Indoor switchgear and controlgear
Subclause 4.1.2 of IEC 62271-1:2017 is applicable.
4.1.3 Outdoor switchgear and controlgear
Subclause 4.1.3 of IEC 62271-1:2017 is applicable.
4.2 Special service conditions
Subclause 4.2 of IEC 62271-1:2017 is applicable.
4.101 Installation in open air
For determining the ratings of GIL for open air installation, the normal service conditions of
IEC 62271-1:2017 shall apply. Typical rating conditions These 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.
4.102 Buried installation
Typical General 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 can be considered.
NOTE 1 For long distance transmission lines (several kilometres), site measurement of soil
resistivity should also be considered.
NOTE 2 1 The use of controlled backfill with a given soil thermal resistivity may can also be considered.
NOTE 3 2 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 should be agreed between manufacturer and user. The determination
of depth of laying shall take into account thermo mechanical stresses, safety requirements and
local regulations.
4.103 Installation in tunnel, shaft or similar situation
Forced cooling is an adequate method to handle with the waste heat and can be used in case
of tunnel, shaft or similar installations.
In the case of long vertical shafts and inclinated inclined tunnels or sections thereof, attention
shall be paid to thermal and density gradients, especially if a gas mixture is used.
5 Ratings
5.1 General
Subclause 5.1 of IEC 62271-1:2017 is not applicable, except and is replaced as follows.
– 10 – IEC 62271-204:2022 RLV © IEC 2022
The rating of a GIL consists of the following:
a) rated voltage (U ) and number of phases;
r
b) rated insulation level (U , U , U ;
d p s)
c) rated frequency (f );
r
d) rated normal continuous 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;
h) rated supply voltage of auxiliary and control circuits (U );
a
i) rated filling pressure of insulating gas.
i) rated supply frequency of auxiliary and control circuits.
5.2 Rated voltage (U )
r
Subclause 4.1 of IEC 62271-203 5.2 of IEC 62271-1:2017 is applicable.
5.3 Rated insulation level (U , U , U )
d p s
Subclause 5.3 of IEC 62271-1:2017 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. For more information, see [1] .
Although internal arcing faults can largely be avoided by the choice of a suitable insulation level,
measures to limit external overvoltages at each end of the installation (e.g. surge arresters)
should be considered.
5.4 Rated frequency (f )
r
Subclause 5.4 of IEC 62271-1:2017 is applicable.
4.4 Rated normal current and temperature rise
5.5 Rated normal continuous current (I )
r
Subclause 5.5 of IEC 62271-1:2017 is applicable with the following addition:
The rated normal continuous current is defined for a single, or a three-phase circuit GIL installed
above ground with an ambient air temperature at 40 °C. For other installation conditions, the
maximum allowable continuous current can differ from the rated continuous current. See
Annex A.
4.4.2 Temperature rise
Subclause 4.4.2 of IEC 62271-1 is applicable with the following addition:
___________
Numbers in square brackets refer to the Bibliography.
The temperature of the enclosure shall not exceed the maximum allowable temperature of the
anti-corrosion coating if applicable.
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.
5.6 Rated short-time withstand current (I )
k
Subclause 5.6 of IEC 62271-1:2017 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.
5.7 Rated peak withstand current (I )
p
Subclause 5.7 of IEC 62271-1:2017 is applicable.
5.8 Rated duration of short-circuit (t )
k
Subclause 5.8 of IEC 62271-1:2017 is applicable.
5.9 Rated supply voltage of closing and opening devices and of auxiliary and control
circuits (U )
a
Subclause 5.9 of IEC 62271-1:2017 is applicable.
5.10 Rated supply frequency of closing and opening devices and of auxiliary and
control circuits
Subclause 5.10 of IEC 62271-1:2017 is applicable with the following addition:.
– 12 – IEC 62271-204:2022 RLV © IEC 2022
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.
5.11 Rated pressure of compressed gas supply for controlled pressure systems
Subclause 5.11 of IEC 62271-1:2017 is not applicable.
4.11 Rated filling levels for insulation and/or operation
Subclause 4.11 of IEC 62271-1 is applicable.
6 Design and construction
Clause 6 of IEC 62271-1:2017 is not applicable, except as follows.
Any component GIL equipment which requires routine preventive maintenance or diagnostic
testing shall should be easily accessible.
GIL shall should 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 should 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.
6.1 Requirements for liquids in GIL
Subclause 6.1 of IEC 62271-1:2017 is not applicable.
6.2 Requirements for gases in GIL
Subclause 6.2 of IEC 62271-1:2017 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 [2], [3] and [4].
6.3 Earthing
Subclause 6.3 of IEC 62271-1:2017 is applicable, except as follows with the following additions.
6.3.101 Earthing of the 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 can be made by
a) earthing switches with a making current capacity equal to the rated peak withstand current,
if there is no certainty still a possibility that the circuit connected is not live;
b) earthing switches without a short-circuit making current capacity capability or with a short-
circuit making capacity capability lower than the rated peak withstand current, if there is a
certainty that the circuit connected is not live, or
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 should 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).
The earthing circuit can be degraded after being subjected to the rated short-circuit current.
After such event, earthing circuit can be replaced if applicable.
6.3.102 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 aluminum 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 can 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 step and touch 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.
6.4 Auxiliary and control equipment
Subclause 6.4 of IEC 62271-1:2017 is applicable.
6.5 Dependent power operation
Subclause 6.5 of IEC 62271-1:2017 is not applicable.
6.6 Stored energy operation
Subclause 6.6 of IEC 62271-1:2017 is not applicable.
6.7 Independent manual or power operation (independent unlatched operation)
Subclause 6.7 of IEC 62271-1:2017 is not applicable.
6.8 Manually operated actuators
Subclause 6.8 of IEC 62271-1:2017 is not applicable.
– 14 – IEC 62271-204:2022 RLV © IEC 2022
6.9 Operation of releases
Subclause 6.9 of IEC 62271-1:2017 is not applicable.
6.10 Low- and high-pressure interlocking and monitoring devices Pressure/level
indication
Subclause 6.10 of IEC 62271-1:2017 is applicable, except as follows.
Means shall be provided for monitoring gas pressure or gas density, taking into account the
relevant IEC standards. It is recommended that signals be provided when the gas pressure for
insulation has fallen to the alarm pressure for insulation and to the minimum functional pressure
for insulation, or risen to the maximum value in the case of controlled pressure system, as
defined by the manufacturer.
6.11 Nameplates
Subclause 6.11 of IEC 62271-1:2017 is not applicable and is replaced as follows:
6.11.1 General
5.10.101 Nameplates
For outdoor installation, the nameplates and their fixings shall be weather-proof and corrosion
proof. Reference is made to IEC 62271-1 subclause 5.10.
A complete nameplate shall be provided at each end of the installation, and at each point where
service is needed. These nameplates shall contain the following information:
– manufacturer's name or trademark
– type designation or and serial number
– rated voltage U
r
– U
rated lightning impulse withstand voltage
p
– rated switching impulse withstand voltage U
s
– rated short-duration power-frequency withstand voltage U
d
– rated normal continuous current I
r
– rated short-time withstand current I
k
– rated peak withstand current I
p
– rated frequency f
r
– rated duration of short-circuit t
k
– rated filling pressure for insulation; minimum functional pressure
for insulation; design pressure for enclosures
– type of gas
– mass of gas contained kg
NOTE The word "rated" need not appear is optional on the nameplates.
___________
The values to be used for nameplates are phase-to-earth values.
5.10.102 Equipment identification
6.11.2 Application
Subclause 6.11.2 of IEC 62271-1:2017 is not applicable and is replaced as follows:
Since characteristics of different sections may can be different, a marking shall be provided on
the enclosure for equipment identification, or on the coating of the enclosure, if any. The
maximum distance between two identification markings shall should be agreed between
manufacturer and user.
Markings shall be durable and clearly legible and shall contain the following information:
– manufacturer's name or trademark;
– type designation;
– rated voltage;
– type of gas and rated filling pressure for insulation.
6.12 Interlocking Locking devices
Subclause 6.12 of IEC 62271-1:2017 is not applicable.
6.13 Position indication
Subclause 6.13 of IEC 62271-1:2017 is not applicable.
6.14 Degree of protection provided by enclosures
6.14.1 General
Subclause 6.14.1 of IEC 62271-1:2017 is applicable with the following additions.
No specification applies to the main circuit and parts directly connected thereto, because of the
gas tightness of the enclosure.
Degrees of protection according to IEC 60529 shall be specified for all enclosures of
appropriate low-voltage control and/or auxiliary circuits.
The degrees of protection apply to the service conditions of the equipment.
6.14.2 Protection of persons against access to hazardous parts and protection of the
equipment against ingress of solid foreign objects (IP coding)
Subclause 6.14.2 of IEC 62271-1:2017 is applicable with the following additions:
Protection means are applicable only for control and/or auxiliary circuits. The first characteristic
numeral shall be 3 or higher.
6.14.3 Protection against ingress of water (IP coding)
Subclause 6.14.3 of IEC 62271-1:2017 is applicable with the following additions:
For installations where the laying conditions impose a risk of ingress of water (buried
installations, installations in trenches, ducts, etc.), the second characteristic numeral shall
be specified. In this case the letter X in the second position of the designation in Table 7 of
IEC 62271-1 is replaced by a numeral as shown in Table 1 below.
– 16 – IEC 62271-204:2022 RLV © IEC 2022
Table 1 – Second characteristic numeral of IP coding
Second characteristic Brief description Definition
numeral
Protected against the effects of Ingress of water causing harmful effects shall
temporary immersion in water not be possible when the enclosure is tempor-
arily immersed in water under standardized
conditions of pressure and time
NOTE For more severe situations than those corresponding to the second characteristic numeral 7, the protection
should be agreed between manufacturer and user.
Equipment for outdoor installation, provided with additional features against rain and other
weather conditions shall be specified by means of the supplementary letter W placed after the
second characteristic numeral, or after the additional letter, if any.
6.14.4 Protection against mechanical impact under normal service conditions
(IK coding)
Subclause 6.14.4 of IEC 62271-1:2017 is applicable.
5.13.101 Degree of protection for the main circuits
No specification applies to the main circuit and parts directly connected thereto, because of the
gas tightness of the enclosure.
5.13.102 Degree of protection for auxiliary circuits
Degrees of protection according to IEC 60529 shall be specified for all enclosures of
appropriate low-voltage control and/or auxiliary circuits.
The degrees of protection apply to the service conditions of the equipment.
6.15 Creepage distances for outdoor insulators
Subclause 6.15 of IEC 62271-1:2017 is not applicable.
6.16 Gas and vacuum tightness
6.16.1 General
Subclause 6.16.1 of IEC 62271-1:2017 is not applicable.
6.16.2 Controlled pressure systems for gas
Not applicable for GIL.
Subclause 6.16.2 of IEC 62271-1:2017 is not applicable.
6.16.3 Closed pressure systems for gas
Subclause 6.16.3 of IEC 62271-203:2022 is applicable with the following additions:
The tightness characteristic of a closed pressure system and the time between replenishment
under normal service condition shall be stated by the manufacturer and shall be consistent with
a minimum maintenance and inspection philosophy.
The tightness of closed pressure systems for gas is specified by the relative leakage rate F
rel
of each compartment; standardized values are:
– for SF and SF mixtures, the standardized value is 0,5 % per year per compartment;
6 6
– for other gases, the standardized value is 0,5 % per year per compartment.
The value for the time between replenishment shall be at least 10 years for SF systems and
for other gases should be consistent with the tightness values. The possible leakages between
subassemblies having different pressures shall also be taken into account. In the particular
case of maintenance in a compartment when adjacent compartments contain gas under
pressure, the permissible gas leakage rate across partitions should also be stated by the
manufacturer, and the time between replenishments shall be not less than one month. Means
shall be provided to enable gas systems to be safely replenished whilst the equipment is in
service.
6.16.4 Sealed pressure systems
Subclause 6.16.4 of IEC 62271-1:2017 is applicable.
The tightness of sealed pressure systems is specified by their expected operating life. The
expected operating life with regard to leakage performance shall be specified by the
manufacturer. Preferred values are 20 years, 30 years and 40 years.
NOTE To fulfil the expected operating life requirement, the leakage rate for SF systems is considered to be 0,1 %
per year.
6.16.5 Internal partitions
If requested by the user, in order to permit maintenance in a compartment when adjacent
compartments contain gas under pressure, the permissible gas leakage across partitions should
also be stated by the manufacturer.
In the particular case of maintenance in a compartment when adjacent compartments contain
gas under pressure, the permissible gas leakage rate across partitions should also be stated
by the manufacturer, and the time between replenishments shall be not less than one month.
Means shall be provided to enable gas systems to be safely replenished whilst the equipment
is in service.
Handling for repair and maintenance shall be carried out according to local regulation, see
IEC 62271-4.
6.17 Liquid tightness Tightness of liquid systems
Subclause 6.17 of IEC 62271-1:2017 is not applicable.
6.18 Fire hazard (flammability)
Subclause 6.18 of IEC 62271-1:2017 is not applicable.
6.19 Electromagnetic compatibility (EMC)
Subclause 6.19 of IEC 62271-1:2017 is not applicable.
6.20 X-ray emission
Subclause 6.20 of IEC 62271-1:2017 is not applicable.
6.21 Corrosion
Subclause 6.21 of IEC 62271-1:2017 is applicable, except as follows with the following
additions:
– 18 – IEC 62271-204:2022 RLV © IEC 2022
6.21.101 Corrosion protection for buried installations
Corrosion protection, i.e. both the external coating and any active protection system, shall take
into account special considerations such as: the location, the soil/backfill material and
conditions, the enclosure material and the type of earthing adopted.
In general, the corrosion protection for GIL is similar to the protection means of normal pipeline
or power cables. The enclosure is coated with rubber or plastic in one or more layers. The
coating acts as a passive corrosion protection system by keeping humidity or water away from
the metal enclosure of the electrical equipment.
In addition to the passive corrosion protection, an active system can be installed in case the
passive system fails. The active corrosion protection system keeps the me
...
IEC 62271-204 ®
Edition 2.0 2022-05
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
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 - 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. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
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 22 300 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 19 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary
(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 IEC gratuitement tous les aperçus des publications. Avec un
en utilisant différents critères (numéro de référence, texte, abonnement, vous aurez toujours accès à un contenu à jour
comité d’études, …). Elle donne aussi des informations sur adapté à vos besoins.
les projets et les publications remplacées ou retirées.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
Le premier dictionnaire d'électrotechnologie en ligne au
Restez informé sur les nouvelles publications IEC. Just
monde, avec plus de 22 300 articles terminologiques en
Published détaille les nouvelles publications parues.
anglais et en français, ainsi que les termes équivalents dans
Disponible en ligne et une fois par mois par email.
19 langues additionnelles. Egalement appelé 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.
IEC 62271-204 ®
Edition 2.0 2022-05
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
INTERNATIONALE
ICS 29.130.10 ISBN 978-2-8322-3804-2
– 2 – IEC 62271-204:2022 © IEC 2022
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Normal and special service conditions . 8
5 Ratings . 9
6 Design and construction . 10
7 Type tests . 21
8 Routine tests . 28
9 Guide to the selection of GIL (informative) . 29
10 Information to be given with enquiries, tenders and orders (informative) . 30
11 Transport, storage, installation, operating instructions and maintenance. 32
12 Safety . 38
13 Influence of the product on the environment . 39
Annex A (informative) Estimation of continuous current . 40
Annex B (informative) Earthing . 45
Annex C (informative) Long-term testing of buried installations . 49
Annex D (normative) Requirements for welds on pressurized parts . 51
Bibliography . 53
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 . 48
Table 1 – Second characteristic numeral of IP coding . 14
Table D.1 – Quantity of NDTs . 51
Table D.2 – Acceptance criteria of imperfections . 52
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.
IEC 62271-204 has been prepared by subcommittee 17C: Assemblies, of IEC technical
committee 17: High-voltage switchgear and controlgear. It is an International Standard.
This second edition cancels and replaces the first edition published in 2011. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) update to be in line with IEC 62271-1:2017 and alignment of the voltage ratings and the test
voltages.
b) addition of new information for welds on pressurized parts and gas tightness.
– 4 – IEC 62271-204:2022 © IEC 2022
The text of this document is based on the following documents:
Draft Report on voting
17C/840/FDIS 17C/846/RVD
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/standardsdev/publications.
This document is to be read in conjunction with IEC 62271-1:2017 and IEC 62271-203:2022, to
which it refers and which are 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 62271-1:2017 and IEC 62271-203:2022. Amendments to these clauses and
subclauses are given under the same numbering, whilst additional subclauses are numbered
from 101.
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 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,
• replaced by a revised edition, or
• amended.
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 204: Rigid gas-insulated transmission lines
for rated voltage above 52 kV
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 an insulating gas or gas mixture other than air at
atmospheric pressure, for alternating current of rated voltages above 52 kV, and for service
frequencies up to and including 60 Hz.
This document is applicable 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 is 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 document, the term "HV gas-insulated transmission line" is abbreviated to "GIL".
NOTE 2 In this document, the word "gas" means gas or gas mixture, as defined by the manufacturer.
NOTE 3 Examples of GIL applications:
– where all or part of the HV gas-insulated transmission line is directly buried;
– where the HV gas-insulated transmission line is located, wholly or partly, in an area accessible to public;
– where the HV gas-insulated transmission line is long (typically longer than 500 m) and the typical gas
compartment length exceeds the common practice of GIS technology.
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 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60229:2007, Electric cables – Tests on extruded oversheaths with a special protective
function
IEC 60287-3-1:2017, Electric cables – Calculation of the current rating – Part 3-1: Operating
conditions – Site reference conditions
IEC 60376, Specification of technical grade sulfur hexafluoride (SF ) and complementary gases
to be used in its mixtures for use in electrical equipment
– 6 – IEC 62271-204:2022 © IEC 2022
IEC 60480, Specifications for the re-use of sulfur hexafluoride (SF ) and its mixtures in
electrical equipment
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60529:1989/AMD1:1999
IEC 60529:1989/AMD2:2013
IEC 62271-1:2017, High-voltage switchgear and controlgear – Part 1: Common specifications
for alternating current switchgear and controlgear
IEC 62271-203:2022, High-voltage switchgear and controlgear – Part 203: AC gas-insulated
metal-enclosed switchgear for rated voltages above 52 kV
IEC 62271-4:2013, High-voltage switchgear and controlgear – Part 4: Handling procedures for
sulphur hexafluoride (SF ) and its mixtures
ISO 9606 (all parts), Qualification test of welders – Fusion welding
ISO 9712, Non-destructive testing – Qualification and certification of NDT personnel
ISO 14732, Welding personnel – Qualification testing of welding operators and weld setters for
mechanized and automatic welding of metallic materials
ISO 15609 (all parts), Specification and qualification of welding procedures for metallic
materials – Welding procedure specification
ISO 15614 (all parts), Specification and qualification of welding procedures for metallic
materials – Welding procedure test
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62271-1:2017 and
the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.101
area accessible to public
area accessible without restriction to any person
Note 1 to entry: A GIL installed above the 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
part of GIL retaining the insulating gas under the required conditions protecting the equipment
against external influences and providing a high degree of protection to personnel
3.104
compartment
part of GIL totally gastight enclosed except for openings necessary for interconnection and
control
3.105
partition
gas tight support insulator of gas-insulated metal-enclosed switchgear separating two adjacent
compartments
3.106
main circuit
all the conductive parts of GIL included in a circuit which is intended to transmit electrical energy
[SOURCE: IEC 60050-441:1984, 441-13-02, modified – Replacement of “an assembly" by
“GIL".]
3.107
ambient air temperature
temperature, determined under required conditions, of the air surrounding the external GIL
enclosure in case of installation in open air, open trenches or tunnels
[SOURCE: IEC 60050-441:1984, 441-11-13, modified – Replacement of “complete switching
device or fuse" by “external GIL enclosure in case of installation in open air, open trenches or
tunnels".]
3.108
design temperature of the enclosure
maximum temperature which can be reached on a GIL enclosure under service conditions
3.109
design pressure of the enclosure
relative pressure used to determine the design of the enclosure
Note 1 to entry: It is at least equal to the maximum relative pressure in the enclosure at the design temperature of
the enclosure.
3.110
design pressure of the partitions
relative pressure across the partition
Note 1 to entry: It is at least equal to the maximum differential pressure across the partition during maintenance
activities.
3.111
disconnecting unit
unit to electrically isolate one side from another of the main circuit, mainly for site testing or
maintenance
3.112
disruptive discharge
phenomenon associated with the failure of insulation under electric stress, in which the dis-
charge completely bridges the insulation, reducing the voltage between the electrodes to zero
or almost zero
Note 1 to entry: The term applies to discharges in solid, liquid and gaseous dielectrics and to combinations of these.
Note 2 to entry: 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 can be only temporary (self-restoring insulation).
– 8 – IEC 62271-204:2022 © IEC 2022
Note 3 to entry: 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
part of GIL which is defined by operational or other requirements such as maximum length for
dielectric testing or installation sequence
Note 1 to entry: A GIL can consist on the assembly of several GIL sections.
Note 2 to entry: It can consist of one or more compartments.
Note 3 to entry: Sections can be segregated by disconnecting units.
4 Normal and special service conditions
4.1 Normal service conditions
4.1.1 General
Subclause 4.1.1 of IEC 62271-1:2017 is applicable with the following addition.
The normal service conditions which apply to a GIL depending on the installation conditions are
given in 4.101, 4.102 and 4.103. When more than one of these installation conditions apply, the
relevant subclause shall apply to each section of the GIL.
4.1.2 Indoor switchgear and controlgear
Subclause 4.1.2 of IEC 62271-1:2017 is applicable.
4.1.3 Outdoor switchgear and controlgear
Subclause 4.1.3 of IEC 62271-1:2017 is applicable.
4.2 Special service conditions
Subclause 4.2 of IEC 62271-1:2017 is applicable.
4.101 Installation in open air
For determining the ratings of GIL for open air installation, the normal service conditions of
IEC 62271-1:2017 shall apply. These are also valid for open trenches.
If the actual service conditions differ from the normal service conditions, the ratings shall be
adapted accordingly.
4.102 Buried installation
General 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 can be considered.
For long distance transmission lines (several kilometres), site measurement of soil resistivity
should also be considered.
NOTE 1 The use of controlled backfill with a given soil thermal resistivity can also be considered.
NOTE 2 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 should be agreed between manufacturer and user. The determination of
depth of laying shall take into account thermo mechanical stresses, safety requirements and
local regulations.
4.103 Installation in tunnel, shaft or similar situation
Forced cooling is an adequate method to handle with the waste heat and can be used in case
of tunnel, shaft or similar installations.
In the case of long vertical shafts and inclined tunnels or sections thereof, attention shall be
paid to thermal and density gradients.
5 Ratings
5.1 General
Subclause 5.1 of IEC 62271-1:2017 is not applicable and is replaced as follows.
The rating of a GIL consists of the following:
a) rated voltage (U );
r
b) rated insulation level (U , U , U ;
d p s)
c) rated frequency (f );
r
d) rated continuous current (I );
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 supply voltage of auxiliary and control circuits (U );
a
i) rated supply frequency of auxiliary and control circuits.
5.2 Rated voltage (U )
r
Subclause 5.2 of IEC 62271-1:2017 is applicable.
5.3 Rated insulation level (U , U , U )
d p s
Subclause 5.3 of IEC 62271-1:2017 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. For more information, see [1] .
Although internal arcing faults can largely be avoided by the choice of a suitable insulation level,
measures to limit external overvoltages at each end of the installation (e.g. surge arresters)
should be considered.
___________
Numbers in square brackets refer to the Bibliography.
– 10 – IEC 62271-204:2022 © IEC 2022
5.4 Rated frequency (f )
r
Subclause 5.4 of IEC 62271-1:2017 is applicable.
5.5 Rated continuous current (I )
r
Subclause 5.5 of IEC 62271-1:2017 is applicable with the following addition:
The rated continuous current is defined for a single or a three-phase GIL installed above ground
with an ambient air temperature at 40 °C. For other installation conditions, the maximum
allowable continuous current can differ from the rated continuous current. See Annex A.
5.6 Rated short-time withstand current (I )
k
Subclause 5.6 of IEC 62271-1:2017 is applicable.
5.7 Rated peak withstand current (I )
p
Subclause 5.7 of IEC 62271-1:2017 is applicable.
5.8 Rated duration of short-circuit (t )
k
Subclause 5.8 of IEC 62271-1:2017 is applicable.
5.9 Rated supply voltage of auxiliary and control circuits (U )
a
Subclause 5.9 of IEC 62271-1:2017 is applicable.
5.10 Rated supply frequency of auxiliary and control circuits
Subclause 5.10 of IEC 62271-1:2017 is applicable.
5.11 Rated pressure of compressed gas supply for controlled pressure systems
Subclause 5.11 of IEC 62271-1:2017 is not applicable.
6 Design and construction
Clause 6 of IEC 62271-1:2017 is applicable, except as follows.
Any GIL equipment which requires routine preventive maintenance or diagnostic testing should
be easily accessible.
GIL should 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 should 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.
6.1 Requirements for liquids in GIL
Subclause 6.1 of IEC 62271-1:2017 is not applicable.
6.2 Requirements for gases in GIL
Subclause 6.2 of IEC 62271-1:2017 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 [2], [3] and [4].
6.3 Earthing
Subclause 6.3 of IEC 62271-1:2017 is applicable, with the following additions.
6.3.101 Earthing of the 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 can be made by
a) earthing switches with a making capacity equal to the rated peak withstand current, if there
is still a possibility that the circuit connected is live;
b) earthing switches without a short-circuit making capability or with a short-circuit making
capability lower than the rated peak withstand current, if there is a certainty that the circuit
connected is not live, or
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 should 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).
The earthing circuit can be degraded after being subjected to the rated short-circuit current.
After such event, earthing circuit can be replaced if applicable.
6.3.102 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 aluminum 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 can 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, step and touch 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.
– 12 – IEC 62271-204:2022 © IEC 2022
6.4 Auxiliary and control equipment
Subclause 6.4 of IEC 62271-1:2017 is applicable.
6.5 Dependent power operation
Subclause 6.5 of IEC 62271-1:2017 is not applicable.
6.6 Stored energy operation
Subclause 6.6 of IEC 62271-1:2017 is not applicable.
6.7 Independent manual or power operation (independent unlatched operation)
Subclause 6.7 of IEC 62271-1:2017 is not applicable.
6.8 Manually operated actuators
Subclause 6.8 of IEC 62271-1:2017 is not applicable.
6.9 Operation of releases
Subclause 6.9 of IEC 62271-1:2017 is not applicable.
6.10 Pressure/level indication
Subclause 6.10 of IEC 62271-1:2017 is applicable.
6.11 Nameplates
Subclause 6.11 of IEC 62271-1:2017 is not applicable and is replaced as follows:
6.11.1 General
For outdoor installation, the nameplates and their fixings shall be weather-proof and corrosion
proof.
A complete nameplate shall be provided at each end of the installation, and at each point where
service is needed. These nameplates shall contain the following information:
– manufacturer's name or trademark
– type designation and serial number
– rated voltage U
r
– rated lightning impulse withstand voltage U
p
– rated switching impulse withstand voltage U
s
– rated short-duration power-frequency withstand voltage U
d
– rated continuous current I
r
– rated short-time withstand current I
k
– rated peak withstand current I
p
– rated frequency f
r
– rated duration of short-circuit t
k
– filling pressure for insulation; minimum functional pressure for
insulation; design pressure for enclosures
– type of gas
– mass of gas
NOTE The word "rated" is optional on the nameplates.
6.11.2 Application
Subclause 6.11.2 of IEC 62271-1:2017 is not applicable and is replaced as follows:
Since characteristics of different sections can be different, a marking shall be provided on the
enclosure for equipment identification, or on the coating of the enclosure, if any. The maximum
distance between two identification markings should be agreed between manufacturer and user.
Markings shall be durable and clearly legible and shall contain the following information:
– manufacturer's name or trademark;
– type designation;
– rated voltage;
– type of gas and filling pressure for insulation.
6.12 Locking devices
Subclause 6.12 of IEC 62271-1:2017 is applicable.
6.13 Position indication
Subclause 6.13 of IEC 62271-1:2017 is applicable.
6.14 Degree of protection provided by enclosures
6.14.1 General
Subclause 6.14.1 of IEC 62271-1:2017 is applicable with the following additions.
No specification applies to the main circuit and parts directly connected thereto, because of the
gas tightness of the enclosure.
Degrees of protection according to IEC 60529 shall be specified for all enclosures of
appropriate low-voltage control and/or auxiliary circuits.
The degrees of protection apply to the service conditions of the equipment.
6.14.2 Protection of persons against access to hazardous parts and protection of the
equipment against ingress of solid foreign objects (IP coding)
Subclause 6.14.2 of IEC 62271-1:2017 is applicable with the following additions:
Protection means are applicable only for control and/or auxiliary circuits. The first characteristic
numeral shall be 3 or higher.
– 14 – IEC 62271-204:2022 © IEC 2022
6.14.3 Protection against ingress of water (IP coding)
Subclause 6.14.3 of IEC 62271-1:2017 is applicable with the following additions:
For installations where the laying conditions impose a risk of ingress of water (buried
installations, installations in trenches, ducts, etc.), the second characteristic numeral shall
be specified as shown in Table 1 below.
Table 1 – Second characteristic numeral of IP coding
Second characteristic Brief description Definition
numeral
7 Protected against the effects of Ingress of water causing harmful effects shall not
temporary immersion in water be possible when the enclosure is temporarily
immersed in water under standardized conditions
of pressure and time
For more severe situations than those corresponding to the second characteristic numeral 7, the protection should
be agreed between manufacturer and user.
6.14.4 Protection against mechanical impact under normal service conditions
(IK coding)
Subclause 6.14.4 of IEC 62271-1:2017 is applicable.
6.15 Creepage distances for outdoor insulators
Subclause 6.15 of IEC 62271-1:2017 is not applicable.
6.16 Gas and vacuum tightness
6.16.1 General
Subclause 6.16.1 of IEC 62271-1:2017 is not applicable.
6.16.2 Controlled pressure systems for gas
Subclause 6.16.2 of IEC 62271-1:2017 is not applicable.
6.16.3 Closed pressure systems for gas
Subclause 6.16.3 of IEC 62271-203:2022 is applicable with the following additions:
The tightness characteristic of a closed pressure system and the time between replenishment
under normal service condition shall be stated by the manufacturer and shall be consistent with
a minimum maintenance and inspection philosophy.
The value for the time between replenishment shall be at least 10 years for SF systems and
for other gases should be consistent with the tightness values. The possible leakages between
subassemblies having different pressures shall also be taken into account.
6.16.4 Sealed pressure systems
Subclause 6.16.4 of IEC 62271-1:2017 is applicable.
6.16.5 Internal partitions
In the particular case of maintenance in a compartment when adjacent compartments contain
gas under pressure, the permissible gas leakage rate across partitions should also be stated
by the manufacturer, and the time between replenishments shall be not less than one month.
Means shall be provided to enable gas systems to be safely replenished whilst the equipment
is in service.
Handling for repair and maintenance shall be carried out according to local regulation, see
IEC 62271-4.
6.17 Tightness of liquid systems
Subclause 6.17 of IEC 62271-1:2017 is not applicable.
6.18 Fire hazard (flammability)
Subclause 6.18 of IEC 62271-1:2017 is not applicable.
6.19 Electromagnetic compatibility (EMC)
Subclause 6.19 of IEC 62271-1:2017 is not applicable.
6.20 X-ray emission
Subclause 6.20 of IEC 62271-1:2017 is not applicable.
6.21 Corrosion
Subclause 6.21 of IEC 62271-1:2017 is applicable, with the following additions:
6.21.101 Corrosion protection for buried installations
Corrosion protection, i.e. both the external coating and any active protection system, shall take
into account special considerations such as: the location, the soil/backfill material and
conditions, the enclosure material and the type of earthing adopted.
In general, the corrosion protection for GIL is similar to the protection means of normal pipeline
or power cables. The enclosure is coated with rubber or plastic in one or more layers. The
coating acts as a passive corrosion protection system by keeping humidity or water away from
the metal enclosure of the electrical equipment.
Passive corrosion protection is required and any active corrosion system, if requested and
installed by mutual agreement between operator and supplier, shall be laid out in accordance
with environmental conditions along the GIL.
6.21.102 Corrosion protection for not buried installations
Subclause 6.21 of IEC 62271-1:2017 is applicable.
6.22 Filling levels for insulation, switching and/or operation
Subclause 6.22 of IEC 62271-1:2017 is applicable.
– 16 – IEC 62271-204:2022 © IEC 2022
6.101 Minimizing of internal fault effects
6.101.1 General
A fault leading to an internal arc fault within GIL built according to this document has a very low
probability. This results from the use of an insulating gas, other than air at atmospheric pressure,
which will not be affected by pollution, humidity or vermin.
Examples of measures to avoid an internal arc fault and to limit duration and consequences are
– insulation coordination,
– gas-leakage limitation and control,
– high-speed protection,
– high-speed arc short-circuiting devices,
– interlocking of switching devices,
– remote control,
– internal and/or external pressure reliefs, and
– checking of workmanship on site.
Arrangements should also be made to minimize the effects of internal arc faults on the continued
service capability of the GIL. The effect of an arc should be confined to the compartment in
which the arc has been initiated.
If, in spite of the measures taken, a test is agreed between manufacturer and user to verify the
effect of internal arc faults, this test should be in accordance with 7.105 of IEC 62271-203:2022.
Tests would normally not be necessary in the case of single-phase enclosed GIL installed in
isolated neutral or resonant earthed systems and equipped with a protection to limit the duration
of internal earth faults.
6.101.2 External effects of the arc
Adequate installation precautions shall be taken in order to reduce the hazards to a tolerable
risk. For more information, see [4].
In order to provide a high protection to personnel, the external effects of an arc shall be limited
(by taking adequate precautions) to the appearance of a hole or tear in the enclosure without
any fragmentation.
The manufacturer shall provide sufficient information to allow the user to take these precautions.
Manufacturer and user can agree upon a time during which an arc due to an internal fault up to
a given value of short-circuit current will cause no external effects (refer also to 6.102.2).
6.101.3 Internal fault location
Appropriate devices shall be available to enable determination of the faults location.
6.102 Enclosures
6.102.1 General
The enclosure shall be of metal, permanently earthed and capable of withstanding the normal
and transient service pressures.
The enclosures of gas-filled equipment conforming to this document are permanently
pressurized in service and are subjected to particular service conditions which distinguish them
from compressed air receivers and similar storage vessels. These conditions are as follows:
– the main circuit is enclose to prevent hazardous approach to live parts and are so shaped
that, when filled at or above the minimum functional gas pressure for insulation (see 5.11),
they meet the rated insulation level (see 5.3) for the equipment (electrical rather than
mechanical considerations predominate in determining the shape and materials employed);
– enclosures are normally filled with a non-corrosive, dry, stable and inert gas, and the gas
shall remain in this condition (with only small fluctuations in pressure) in order to ensure
correct operation of the installation. However, since the enclosures will not be subject to
internal corrosion, there is no need to make allowances for these factors in determining the
design of the enclosures (but, the effect of possible transmitted vibrations should be taken
into account).
For outdoor installation, the manufacturer shall take into account the influence of climatic
conditions (see Clause 4).
For buried installation, environment conditions shall be taken into account. Concerning the
prevention of external corrosion, see 6.21.
6.102.2 Design of enclosures
The wall thickness of the enclosure shall be based on the design pressure as well as the
following minimum withstand durations in case of an internal arc without burn-through:
– 0,1 s for short-circuit currents of 40 kA and above;
– 0,2 s for lower short-circuit currents.
In order to minimize the risk of burn-through, the level and duration of the fault current, the
enclosure design and the size of the compartments shall be carefully coordinated.
In the absence of an international agreement on a standard procedure, methods for calculating
the thickness and the construction of enclosures, either by welding or casting, can be chosen
from established relevant pressure vessel and pipeline codes, based on the design temperature
and design pressure defined in this document.
When designing an enclosure, account should also be taken of the following:
– the possible evacuation of the enclosure as part of the normal filling process;
– the full differential pressure that is possible across the enclosure walls or partitions;
– the resulting pressure between compartments in the event of an abnormal leak in the case
adjacent compartments have different filling pressures;
– the possibility of the occurrence of an internal fault (see 6.101).
The design temperature of the enclosure is generally the upper limit of the ambient temperature
taking into consideration the increase in temperature rise due to the flow of rated continuous
current. Solar radiations should be considered when they have
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...