SIST-TS CLC IEC/TS 62271-318:2026

SLOVENSKI STANDARD
01-marec-2026
Visokonapetostne stikalne in krmilne naprave - 318. del: Plinsko izolirane stikalne
naprave v kovinskih ohišjih (DC) za naznačene napetosti vključno s 100 kV in več
(IEC/TS 62271-318:2024)
High-voltage switchgear and controlgear - Part 318: DC gas-insulated metal-enclosed
switchgear for rated voltages including and above 100 kV (IEC/TS 62271-318:2024)
Hochspannungs-Schaltgeräte und -Schaltanlagen - Teil 318: Metallgekapselte
gasisolierte Gleichstrom-Schaltanlagen für Bemessungsspannungen größer oder gleich
100 kV (IEC/TS 62271-318:2024)
Appareillage haute tension - Partie 318: Appareillage à courant continu sous enveloppe
métallique à isolation gazeuse de tension assignée supérieure ou égale à 100 kV
(IEC/TS 62271-318:2024)
Ta slovenski standard je istoveten z: CLC IEC/TS 62271-318:2025
ICS:
29.130.10 Visokonapetostne stikalne in High voltage switchgear and
krmilne naprave controlgear
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION CLC IEC/TS 62271-318

SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION December 2025
ICS 29.130.10
English Version
High-voltage switchgear and controlgear - Part 318: DC gas-
insulated metal-enclosed switchgear for rated voltages including
and above 100 kV
(IEC/TS 62271-318:2024)
Appareillage haute tension - Partie 318: Appareillage à Hochspannungs-Schaltgeräte und -Schaltanlagen - Teil
courant continu sous enveloppe métallique à isolation 318: Metallgekapselte gasisolierte Gleichstrom-
gazeuse de tension assignée supérieure ou égale à 100 kV Schaltanlagen für Bemessungsspannungen größer oder
(IEC/TS 62271-318:2024) gleich 100 kV
(IEC/TS 62271-318:2024)
This Technical Specification was approved by CENELEC on 2025-12-08.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to make the TS available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC IEC/TS 62271-318:2025 E

European foreword
This document (CLC IEC/TS 62271-318:2025) consists of the text of IEC/TS 62271-318:2024 prepared
by IEC/TC 17 "High-voltage switchgear and controlgear".
This document is read in conjunction with CLC IEC/TS 62271-5:2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Technical Specification/Technical Report IEC/TS 62271-318:2024 was
approved by CENELEC as a European Technical Specification/Technical Report without any
modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60071-12:2022 NOTE Approved as EN IEC 60071-12:2022 (not modified)
IEC 61672-1:2013 NOTE Approved as EN 61672-1:2013 (not modified)
IEC 61672-2:2013 NOTE Approved as EN 61672-2:2013 (not modified)
IEC 62271-203:2022 NOTE Approved as EN IEC 62271-203:2022 (not modified)
IEC 62271-207:2023 NOTE Approved as EN IEC 62271-207:2023 (not modified)
IEC 63360 NOTE Approved as EN IEC 63360
IEC 60071-11 NOTE Approved as EN IEC 60071-11

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60060-1 2010 High-voltage test techniques - Part 1: EN 60060-1 2010
General definitions and test requirements
IEC 60085 2007 Electrical insulation - Thermal evaluation EN 60085 2008
and designation
IEC 60068-2-11 2021 Environmental testing - Part 2-11: Tests - EN IEC 60068-2-11 2021
Test Ka: Salt mist
IEC 60068-2-17 2023 Environmental testing - Part 2-17: Tests - EN IEC 60068-2-17 2023
Test Q: Sealing
IEC/IEEE 60076-57- 2017 Power transformers - Part 57-129: - -
129 Transformers for HVDC applications
IEC 60099-4 2014 Surge arresters - Part 4: Metal-oxide surge EN 60099-4 2014
arresters without gaps for a.c. systems
IEC 60099-9 2014 Surge arresters - Part 9: Metal-oxide surge EN 60099-9 2014
arresters without gaps for HVDC converter
stations
IEC 60137 2017 Insulated bushings for alternating voltages EN 60137 2017
above 1000 V
IEC 60270 2000 High-voltage test techniques - Partial EN 60270 2001
discharge measurements
+ A1 2015 + A1 2016
IEC 60376 2018 Specification of technical grade sulphur EN IEC 60376 2018
hexafluoride (SF6) and complementary
gases to be used in its mixtures for use in
electrical equipment
IEC 60480 2019 Specifications for the re-use of sulphur EN IEC 60480 2019
hexafluoride (SF6) and its mixtures in
electrical equipment
IEC/TS 60815-1 2008 Selection and dimensioning of high-voltage - -
insulators intended for use in polluted
conditions - Part 1: Definitions, information
and general principles
Publication Year Title EN/HD Year
IEC/TS 60815-4 2016 Selection and dimensioning of high-voltage - -
insulators intended for use in polluted
conditions - Part 4: Insulators for d.c.
systems
IEC 61869-14 2018 Instrument transformers - Part 14: EN IEC 61869-14 2019
Additional requirements for current
transformers for DC applications
IEC 61869-15 2018 Instrument transformers - Part 15: EN IEC 61869-15 2019
Additional requirements for voltage
transformers for DC applications
IEC 62271-1 2017 High-voltage switchgear and controlgear - EN 62271-1 2017
Part 1: Common specifications for
alternating current switchgear and
controlgear
IEC 62271-4 - High-voltage switchgear and controlgear - EN IEC 62271-4 -
Part 4: Handling procedures for gases for
insulation and/or switching
IEC/TS 62271-5 2024 High-voltage switchgear and controlgear - CLC IEC/TS 62271- 2025
Part 5: Common specifications for direct 5
current switchgear and controlgear
IEC 62271-209 2019 High-voltage switchgear and controlgear - EN IEC 62271-209 2019
Part 209: Cable connections for gas-
insulated metal-enclosed switchgear for
rated voltages above 52 kV - Fluid-filled
and extruded insulation cables - Fluid-filled
and dry-type cable-terminations
+ AMD1 2022 + A1 2022
IEC 62271-211 2014 High-voltage switchgear and controlgear - EN 62271-211 2014
Part 211: Direct connection between power
transformers and gas-insulated metal-
enclosed switchgear for rated voltages
above 52 kV
IEC/TR 62271-306 2012 High-voltage switchgear and controlgear - - -
Part 306: Guide to IEC 62271-100, IEC
62271-1 and other IEC standards related
to alternating current circuit-breakers
+ A1 2018 - -
IEC/TS 62271-313 - High-voltage switchgear and controlgear - - -
Part 313: Direct current circuit-breakers
IEC/TS 62271-314 2024 High-voltage switchgear and controlgear - CLC IEC/TS 62271- 2025
Part 314: Direct current disconnectors and 314
earthing switches
IEC/TS 62271-315 2025 High-voltage switchgear and controlgear - - -
Part 315: Direct current (DC) transfer
switches
IEC 62895 2017 High voltage direct current (HVDC) power - -
transmission - Cables with extruded
insulation and their accessories for rated
voltages up to 320 kV for land applications
- Test methods and requirements
Publication Year Title EN/HD Year
ISO 22479 2019 Corrosion of metals and alloys - Sulfur EN ISO 22479 2022
dioxide test in a humid atmosphere (fixed
gas method)
IEC/IEEE 65700-19- 2014 Bushings for DC application EN IEC/IEEE 2018
03 65700-19-03
- - + AC 2019-03
IEC TS 62271-318 ®
Edition 1.0 2024-09
TECHNICAL
SPECIFICATION
High-voltage switchgear and controlgear –

Part 318: DC gas-insulated metal-enclosed switchgear for rated voltages

including and above 100 kV
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.130.10  ISBN 978-2-8322-9674-5

– 2 – IEC TS 62271-318:2024 © IEC 2024
CONTENTS
FOREWORD . 8
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 12
4 Normal and special service conditions . 16
4.1 Normal service conditions . 16
4.2 Special service conditions . 16
4.101 General . 17
5 Ratings . 17
5.1 General . 17
5.2 Rated direct voltage (U ) . 17
rd
5.3 Rated insulation level (U , U , U ) . 18
dd p s
5.4 Rated continuous current (I ) . 18
rd
5.5 Rated values of short-time withstand current . 18
5.5.1 Typical waveform of short-circuit current . 18
5.5.2 Rated short-time withstand direct current (I ) . 18
kd
5.5.3 Rated peak withstand current (I ) . 18
pd
5.5.4 Rated duration of short-circuit (t ) . 18
kd
5.6 Rated supply voltage of auxiliary and control circuits (U ) . 18
a
5.7 Rated supply frequency of auxiliary and control circuits . 18
5.8 Rated pressure of compressed gas supply for controlled pressure systems . 18
6 Design and construction . 19
6.1 Requirements for liquids in switchgear and controlgear . 19
6.2 Requirements for gases in switchgear and controlgear . 19
6.3 Earthing of switchgear and controlgear . 19
6.3.101 Earthing of the main circuit . 19
6.3.102 Earthing of the enclosure . 19
6.4 Auxiliary and control equipment and circuits . 19
6.5 Dependent power operation . 19
6.6 Stored energy operation . 19
6.7 Independent unlatched operation (independent manual or power operation) . 19
6.8 Manually operated actuators . 20
6.9 Operation of releases . 20
6.10 Pressure/level indication . 20
6.11 Nameplates. 20
6.12 Locking devices . 21
6.13 Position indication . 21
6.14 Degrees of protection provided by enclosures . 21
6.15 Creepage distances for outdoor insulators . 21
6.16 Gas and vacuum tightness . 21
6.16.1 General . 21
6.16.2 Controlled pressure systems for gas . 21
6.16.3 Closed pressure systems for gas . 21
6.16.4 Sealed pressure systems . 22
6.16.101 Leakage . 22

IEC TS 62271-318:2024 © IEC 2024 – 3 –
6.16.102 Gas handling . 22
6.17 Tightness for liquid systems . 22
6.18 Fire hazard (flammability) . 22
6.19 Electromagnetic compatibility (EMC) . 22
6.20 X-Ray emission . 22
6.21 Corrosion . 23
6.22 Filling levels for insulation, switching and/or operation . 23
6.101 General requirements for DC GIS . 23
6.102 Pressure coordination . 23
6.103 Internal arc fault . 24
6.103.1 General . 24
6.103.2 External effects of the arc . 25
6.103.3 Internal fault location . 26
6.104 Enclosures . 26
6.104.1 General . 26
6.104.2 Design of enclosures . 26
6.105 Partitions . 27
6.105.1 Design of partitions . 27
6.105.2 Partitioning . 27
6.106 Pressure relief . 29
6.106.1 General . 29
6.106.2 Non-reclosing pressure relief device . 29
6.106.3 Pressure relief valve . 29
6.106.4 Limitation of pressure rise in the case of an internal fault. 30
6.107 Noise . 30
6.108 Interfaces . 30
6.108.1 General . 30
6.108.2 Cable connections . 30
6.108.3 Direct transformer connections . 31
6.108.4 Bushings . 31
6.108.5 Interfaces for future extensions. 31
6.109 Interlocking . 32
7 Type tests . 32
7.1 General . 32
7.1.1 General remarks . 32
7.1.2 Information for identification of test objects . 33
7.1.3 Information to be included in type-test reports . 33
7.2 Dielectric tests . 33
7.2.1 General . 33
7.2.2 Ambient air conditions during tests . 34
7.2.3 Wet test procedure . 34
7.2.4 Arrangement of the equipment . 34
7.2.5 Criteria to pass the test . 34
7.2.6 Application of the test voltage and test conditions . 34
7.2.7 Tests of switchgear and controlgear . 35
7.2.8 Artificial pollution tests for outdoor insulators . 36
7.2.9 Partial discharge tests . 36
7.2.10 Dielectric tests on auxiliary and control circuits . 38
7.2.11 Voltage test as condition check . 38

– 4 – IEC TS 62271-318:2024 © IEC 2024
7.2.101 DC insulation system test . 38
7.2.102 Long-term energized test . 41
7.3 Resistance measurement . 41
7.3.1 Measurement of the resistance of auxiliary contacts class 1 and class 2. 41
7.3.2 Measurement of the resistance of auxiliary contacts class 3 . 41
7.3.3 Electrical continuity of earthed metallic parts test . 41
7.3.4 Resistance measurement of contacts and connections in the main
circuit as a condition check . 42
7.4 Continuous current tests . 42
7.4.1 Conditions of the test object . 42
7.4.2 Arrangement of the equipment . 42
7.4.3 Test current and duration . 42
7.4.4 Temperature measurement during test . 42
7.4.5 Resistance of the main circuit . 43
7.4.6 Criteria to pass test . 43
7.5 Short-time withstand current and peak withstand current tests . 43
7.5.1 General . 43
7.5.2 Arrangement of the equipment and of the test circuit . 43
7.5.3 Test current and duration . 43
7.5.4 Conditions of the test object after test . 43
7.5.101 Tests on the main circuits . 43
7.5.102 Tests on earthing circuits . 44
7.6 Verification of the protection . 44
7.6.1 General . 44
7.6.2 Verification of the IP coding . 44
7.6.3 Verification of the IK coding . 44
7.7 Tightness tests . 44
7.7.1 General . 44
7.7.2 Controlled pressure systems for gas . 44
7.7.3 Closed pressure systems for gas . 45
7.7.4 Sealed pressure systems . 45
7.7.5 Liquid tightness tests . 45
7.8 Electromagnetic compatibility tests (EMC) . 45
7.9 Additional tests on auxiliary and control circuits . 45
7.10 X-radiation test for vacuum interrupters . 45
7.101 Verification of making and breaking capacities . 45
7.102 Mechanical and environmental tests . 45
7.102.1 General . 45
7.102.2 Mechanical operation test at ambient temperature . 45
7.102.3 Low- and high-temperature test . 46
7.103 Proof tests for enclosures . 46
7.103.1 General . 46
7.103.2 Burst test procedure . 46
7.103.3 Strain measurement test . 47
7.104 Pressure test on partitions . 47
7.105 Test under conditions of arcing due to an internal fault . 48
7.106 Insulator tests . 48
7.106.1 General . 48
7.106.2 Thermal performance . 48

IEC TS 62271-318:2024 © IEC 2024 – 5 –
7.106.3 Tightness test for partitions . 49
7.107 Corrosion test on earthing connections . 49
7.107.1 General . 49
7.107.2 Test procedure . 49
7.107.3 Criteria to pass the test . 49
7.108 Corrosion tests on sealing systems of enclosures and auxiliary equipment . 50
7.108.1 General . 50
7.108.2 Test procedure . 50
7.108.3 Criteria to pass the test . 50
8 Routine tests . 50
8.1 General . 50
8.2 Dielectric test on the main circuit . 51
8.2.101 Alternating or direct voltage tests on the main circuit . 51
8.2.102 Partial discharge measurement . 51
8.3 Tests on auxiliary and control circuits . 51
8.4 Measurement of the resistance of the main circuit . 52
8.5 Tightness test . 52
8.6 Design and visual checks . 52
8.101 Pressure tests of enclosures . 52
8.102 Mechanical operation tests . 52
8.103 Tests on auxiliary circuits, equipment and interlocks in the control

mechanism . 53
8.104 Pressure test on partitions . 53
9 Guide to the selection of switchgear and controlgear (informative) . 53
9.1 General . 53
9.2 Selection of rated values . 53
9.3 Cable-interface considerations . 53
9.4 Continuous or temporary overload due to changed service conditions . 53
9.5 Environmental aspects . 53
10 Information to be given with enquiries, tenders and orders (informative) . 54
10.1 General . 54
10.2 Information with enquiries and orders . 54
10.3 Information with tenders . 54
11 Transport, storage, installation, operating instructions and maintenance. 54
11.1 General . 54
11.2 Conditions during transport, storage and installation . 54
11.3 Installation . 54
11.4 Operating instructions . 54
11.5 Maintenance . 54
11.101 Tests after installation on-site . 54
11.101.1 General . 54
11.101.2 Dielectric tests on the main circuits . 55
11.101.3 Dielectric tests on auxiliary circuits . 59
11.101.4 Measurement of the resistance of the main circuit . 59
11.101.5 Gas tightness tests . 59
11.101.6 Checks and verifications . 59
11.101.7 Gas quality verifications . 59
12 Safety . 60

– 6 – IEC TS 62271-318:2024 © IEC 2024
13 Influence of the product on the environment . 60
Annex A (normative) Methods for alternating current testing of DC gas-insulated
metal-enclosed switchgear under conditions of arcing due to an internal fault . 61
A.1 General . 61
A.2 Short-circuit current arcing test . 61
A.2.1 Test arrangements . 61
A.2.2 Current and voltage applied . 61
A.2.3 Test procedure . 62
A.2.4 Criteria to pass the test . 62
A.2.5 Test report . 63
A.2.6 Extension of the test results . 63
A.3 Composite verification by calculation and separate tests . 63
Annex B (informative) Technical and practical considerations of site testing . 64
B.1 Test voltage generators . 64
B.2 Locating discharges . 64
B.3 Special test procedures . 64
B.3.1 General . 64
B.3.2 Testing at reduced voltage. 65
B.3.3 Testing at reduced gas density . 65
B.4 Partial discharge measurements . 65
B.5 Electrical conditioning . 65
B.6 Repetition tests . 65
B.6.1 General . 65
B.6.2 Recommended procedure . 66
B.7 Partial discharge detection method . 66
B.7.1 General . 66
B.7.2 Conventional method according to IEC 60270 . 66
B.7.3 VHF/UHF method . 66
B.7.4 Acoustic method . 67
B.7.5 Sensitivity verification of acoustic and UHF method . 68
Annex C (informative) Calculation of pressure rise due to an internal fault . 69
Annex D (informative) Information to be given with enquiries, tenders and orders . 70
D.1 General . 70
D.2 Normal and special service conditions . 70
D.3 Ratings . 71
D.4 Design and construction . 72
D.5 Bus ducts . 72
D.6 Disconnector and earthing switch . 73
D.7 Bushing . 73
D.8 Cable connection . 73
D.9 Transformer connection . 74
D.10 Current transducer . 74
D.11 Voltage transducer . 74
D.12 Metal-oxide surge arrester . 74
D.13 Documentation for enquiries and tenders . 75
Annex E (informative) List of notes concerning certain countries . 76
Annex F (informative) Long-term energized test . 77
F.1 Test objects . 77

IEC TS 62271-318:2024 © IEC 2024 – 7 –
F.2 Test sequence . 77
F.3 Pre-test . 79
F.4 Condition check . 79
F.5 Success criteria, re-testing and interruptions . 79
Annex G (informative) Application of DC GIS under composite voltage of alternating

and direct voltage components . 81
G.1 General . 81
G.2 Composite voltage consisting of alternating and direct voltage components . 81
G.3 Recommendation for application of DC GIS in bipolar DC schemes under

composite voltage stress . 82
Annex H (informative) DC switchgear located on neutral buses . 83
Bibliography . 84

Figure 1 – Pressure coordination . 24
Figure 2 – Example of arrangement of enclosures and gas compartments . 29
Figure G.1 – Composite phase-to-earth voltage at midpoint of converter pole including
third harmonic content and simplified voltage curve . 81

Table 1 – Reference table of service conditions relevant to DC GIS . 17
Table 2 – Performance criteria . 25
Table 3 – Type tests . 33
Table 4 – Test voltage for measuring PD intensity . 37
Table 5 – Sequence of DC insulation system test . 40
Table 6 – On-site test voltages . 57
Table D.1 – Normal and special service conditions . 70
Table D.2 – Ratings . 71
Table D.3 – Design and construction. 72
Table D.4 – Bus ducts . 72
Table D.5 – Bushing . 73
Table D.6 – Cable connection . 73
Table D.7 – Transformer connection . 74
Table D.8 – Current transducer . 74
Table D.9 – Voltage transducer . 74
Table D.10 – Documentation for enquiries and tenders . 75
Table F.1 – Test sequence for long-term energized test . 77
Table F.2 – Test sequence for long-term energized test with combined switching and
lightning impulse voltage tests and changed sequence . 78
Table F.3 – Test procedure for the long-term energized test . 79
Table F.4 – Condition check for the long-term energized test . 79

– 8 – IEC TS 62271-318:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 318: DC gas-insulated metal-enclosed switchgear
for rated voltages including and above 100 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. Intern
...