IEC TS 62271-5:2024

IEC TS 62271-5 ®
Edition 1.0 2024-05
TECHNICAL
SPECIFICATION
High-voltage switchgear and controlgear –
Part 5: Common specifications for direct current switchgear and controlgear

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IEC TS 62271-5 ®
Edition 1.0 2024-05
TECHNICAL
SPECIFICATION
High-voltage switchgear and controlgear –

Part 5: Common specifications for direct current switchgear and controlgear

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.130.10  ISBN 978-2-8322-8774-3

– 2 – IEC TS 62271-5:2024 © IEC 2024
CONTENTS
FOREWORD . 9
INTRODUCTION . 11
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 14
3.1 General terms and definitions . 14
3.2 Assemblies of switchgear and controlgear . 19
3.3 Parts of assemblies . 19
3.4 Switching devices . 19
3.5 Parts of switchgear and controlgear . 21
3.6 Operational characteristics of switchgear and controlgear . 25
3.6.5 Terms and definitions relative to pressure (or density) . 26
3.6.6 Terms and definitions relating to gas and vacuum tightness . 27
3.6.7 Terms and definitions relating to liquid tightness. 29
3.7 Characteristic quantities . 29
3.8 Index of definitions . 30
4 Normal and special service conditions . 33
4.1 Normal service conditions . 33
4.1.1 General . 33
4.1.2 Indoor switchgear and controlgear . 33
4.1.3 Outdoor switchgear and controlgear . 34
4.2 Special service conditions . 34
4.2.1 General . 34
4.2.2 Altitude . 34
4.2.3 Exposure to pollution . 35
4.2.4 Temperature and humidity . 35
4.2.5 Exposure to abnormal vibrations, shock or tilting . 35
4.2.6 Wind speed . 35
4.2.7 Other parameters . 35
5 Ratings . 36
5.1 General . 36
5.2 Rated direct voltage (U ) . 36
rd
5.2.1 General . 36
5.2.2 Rated voltages . 37
5.3 Rated insulation level (U , U , U ) . 37
dd p s
5.4 Rated continuous current (I ) . 40
rd
5.5 Rated values of short-time withstand current . 40
5.5.1 Typical waveform of short-circuit current . 40
5.5.2 Rated short-time withstand direct current (I ) . 43
kd
5.5.3 Rated peak withstand current (I ) . 43
pd
5.5.4 Rated duration of short-circuit (t ) . 43
kd
5.6 Rated supply voltage of auxiliary and control circuits (U ) . 43
a
5.6.1 General . 43
5.6.2 Rated supply voltage (U ) . 44
a
5.7 Rated supply frequency of auxiliary and control circuits . 44

6 Design and construction . 45
6.1 Requirements for liquids in switchgear and controlgear . 45
6.2 Requirements for gases in switchgear and controlgear . 45
6.3 Earthing of switchgear and controlgear . 45
6.4 Auxiliary and control equipment and circuits . 45
6.4.1 General . 45
6.4.2 Protection against electric shock . 46
6.4.3 Components installed in enclosures . 46
6.5 Dependent power operation . 50
6.6 Stored energy operation . 50
6.6.1 General . 50
6.6.2 Energy storage in gas receivers or hydraulic accumulators . 50
6.6.3 Energy storage in springs (or weights) . 50
6.6.4 Manual charging . 50
6.6.5 Motor charging . 51
6.6.6 Energy storage in capacitors . 51
6.7 Independent unlatched operation (independent manual or power operation) . 51
6.8 Manually operated actuators . 51
6.9 Operation of releases . 51
6.9.1 General . 51
6.9.2 Shunt closing release . 52
6.9.3 Shunt opening release . 52
6.9.4 Capacitor operation of shunt releases . 52
6.9.5 Under-voltage release . 52
6.10 Pressure/level indication . 52
6.10.1 Gas pressure . 52
6.10.2 Liquid level . 52
6.11 Nameplates. 53
6.11.1 General . 53
6.11.2 Application . 53
6.12 Locking devices . 54
6.13 Position indication . 55
6.14 Degrees of protection provided by enclosures . 55
6.14.1 General . 55
6.14.2 Protection of persons against access to hazardous parts and protection
of the equipment against ingress of solid foreign objects (IP coding) . 55
6.14.3 Protection against ingress of water (IP coding) . 55
6.14.4 Protection against mechanical impact under normal service conditions
(IK coding) . 55
6.15 Creepage distances for outdoor insulators . 55
6.16 Gas and vacuum tightness . 56
6.16.1 General . 56
6.16.2 Controlled pressure systems for gas . 56
6.16.3 Closed pressure systems for gas . 56
6.16.4 Sealed pressure systems . 56
6.17 Tightness for liquid systems . 57
6.17.1 General . 57
6.17.2 Leakage rates . 57
6.18 Fire hazard (flammability) . 57

– 4 – IEC TS 62271-5:2024 © IEC 2024
6.19 Electromagnetic compatibility (EMC) . 57
6.20 X-ray emission . 57
6.21 Corrosion . 57
6.22 Filling levels for insulation, switching and/or operation . 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
7.2 Dielectric tests . 59
7.2.1 General . 59
7.2.2 Ambient air conditions during tests . 59
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 the test voltage and test conditions . 61
7.2.7 Tests of switchgear and controlgear . 63
7.2.8 Artificial pollution tests for outdoor insulators . 65
7.2.9 Partial discharge tests . 65
7.2.10 Dielectric tests on auxiliary and control circuits . 65
7.2.11 Voltage test as condition check . 65
7.3 Resistance measurement . 66
7.3.1 Measurement of the resistance of auxiliary contacts class 1 and class 2. 66
7.3.2 Measurement of the resistance of auxiliary contacts class 3 . 66
7.3.3 Electrical continuity of earthed metallic parts test . 66
7.3.4 Resistance measurement of contacts and connections in the main
circuit as a condition check . 66
7.4 Continuous current tests . 67
7.4.1 Condition of the test object . 67
7.4.2 Arrangement of the equipment . 67
7.4.3 Test current and duration . 68
7.4.4 Temperature measurement during test . 69
7.4.5 Resistance of the main circuit . 70
7.4.6 Criteria to pass test . 70
7.5 Short-time withstand current and peak withstand current tests . 74
7.5.1 General . 74
7.5.2 Arrangement of the equipment and of the test circuit . 74
7.5.3 Test current and duration . 75
7.5.4 Conditions of the test object after test . 76
7.6 Verification of the protection . 76
7.6.1 Verification of the IP coding . 76
7.6.2 Verification of the IK coding . 76
7.7 Tightness tests . 77
7.7.1 General . 77
7.7.2 Controlled pressure systems for gas . 78
7.7.3 Closed pressure systems for gas . 78
7.7.4 Sealed pressure systems . 79
7.7.5 Liquid tightness tests . 79
7.8 Electromagnetic compatibility tests (EMC) . 79

7.8.1 Emission tests . 79
7.8.2 Immunity tests on auxiliary and control circuits . 82
7.8.3 Additional EMC tests on auxiliary and control circuits . 85
7.9 Additional tests on auxiliary and control circuits . 86
7.9.1 General . 86
7.9.2 Functional tests . 86
7.9.3 Verification of the operational characteristics of auxiliary contacts . 86
7.9.4 Environmental tests . 87
7.9.5 Dielectric test . 88
7.10 X-radiation test for vacuum interrupters . 88
7.10.1 General requirements . 88
7.10.2 Test voltage and measurement procedure . 90
7.10.3 Acceptance criteria . 90
8 Routine tests . 91
8.1 General . 91
8.2 Dielectric test on the main circuit . 91
8.3 Tests on auxiliary and control circuits . 91
8.3.1 Inspection of auxiliary and control circuits, and verification of conformity
to the circuit diagrams and wiring diagrams . 91
8.3.2 Functional tests . 92
8.3.3 Verification of protection against electrical shock . 92
8.3.4 Dielectric tests . 92
8.4 Measurement of the resistance of the main circuit . 92
8.5 Tightness test . 93
8.5.1 General . 93
8.5.2 Controlled pressure systems for gas . 93
8.5.3 Closed pressure systems for gas . 93
8.5.4 Sealed pressure systems . 93
8.5.5 Liquid tightness tests . 93
8.6 Design and visual checks . 93
9 Guide to the selection of switchgear and controlgear (informative) . 94
9.1 General . 94
9.2 Selection of rated values . 94
9.3 Cable-interface considerations . 94
9.4 Continuous or temporary overload due to changed service conditions . 94
9.5 Environmental aspects . 94
9.5.1 Service conditions . 94
9.5.2 Clearances affected by service conditions . 94
9.5.3 High humidity . 94
9.5.4 Solar radiation . 95
10 Information to be given with enquiries, tenders and orders (informative) . 95
10.1 General . 95
10.2 Information with enquiries and orders . 95
10.3 Information with tenders . 96
11 Transport, storage, installation, operating instructions and maintenance. 97
11.1 General . 97
11.2 Conditions during transport, storage and installation . 97
11.3 Installation . 97
11.3.1 General . 97

– 6 – IEC TS 62271-5:2024 © IEC 2024
11.3.2 Unpacking and lifting . 97
11.3.3 Assembly . 98
11.3.4 Mounting . 98
11.3.5 Connections . 98
11.3.6 Information about gas and gas mixtures for controlled and closed

pressure systems . 98
11.3.7 Final installation inspection . 99
11.3.8 Basic input data by the user . 99
11.3.9 Basic input data by the manufacturer . 99
11.4 Operating instructions . 100
11.5 Maintenance . 100
11.5.1 General . 100
11.5.2 Information about fluids and gas to be included in maintenance manual . 100
11.5.3 Recommendations for the manufacturer . 100
11.5.4 Recommendations for the user . 101
11.5.5 Failure report . 102
12 Safety . 103
12.1 General . 103
12.2 Precautions by manufacturers . 104
12.3 Precautions by users . 104
13 Influence of the product on the environment . 105
Annex A (informative) Examples of HVDC side switchgear arrangement for one pole in
an HVDC substation . 106
Annex B (informative) Exposure to pollution . 108
B.1 General . 108
B.2 Minimum requirements for switchgear in normal service condition. 108
B.3 Minimum requirements for switchgear in special service condition . 108
Annex C (informative) Preferred insulation levels for rated voltages lower than 105 kV . 109
Annex D (informative) Short-circuit current in HVDC systems . 110
D.1 VSC HVDC . 110
D.2 LCC HVDC . 111
D.3 Special case of LCC HVDC DC faults – LCC as diode bridge . 111
D.4 HVDC systems with DC circuit-breakers. 113
D.5 Calculation of the rated short-time withstand direct current . 114
D.6 Calculation of Joule integral value (E ) . 115
j
Annex E (informative) References for auxiliary and control circuit components . 116
Annex F (informative) List of symbols . 118
Annex G (normative) Method for the weatherproofing test for outdoor switchgear and
controlgear . 120
Annex H (normative) Tolerances on test quantities during tests . 123
Annex I (informative) Extension of validity of type tests. 126
I.1 General . 126
I.2 Dielectric tests . 126
I.3 Short-time withstand current and peak withstand current tests . 126
I.4 Electromagnetic immunity test on auxiliary and control circuits . 126
I.5 Environmental tests on auxiliary and control circuits . 126
Annex J (normative) Identification of test objects . 128
J.1 General . 128

J.2 Data . 128
J.3 Drawings. 128
Annex K (informative) Test circuit for superimposed impulse voltage tests . 130
K.1 General . 130
K.2 Test circuit using blocking capacitor . 130
K.3 Test circuit using sphere gap . 130
Annex L (informative) Information and technical requirements to be given with
enquiries, tenders and orders . 132
L.1 General . 132
L.2 Normal and special service conditions (refer to Clause 4) . 132
L.3 Ratings (refer to Clause 5) . 133
L.4 Design and construction (refer to Clause 6) . 133
L.5 System information . 134
L.6 Documentation for enquiries and tenders . 134
Annex M (informative) Electromagnetic compatibility on site . 135
Annex N (informative) Standardization activities of HVDC . 136
Bibliography . 137

Figure 1 – Schematic representation of superimposed impulse voltage tests . 40
Figure 2 – Typical waveform of a short-circuit current in an HVDC system . 42
Figure 3 – Examples of classes of contacts. 49
Figure 4 – Diagram of connections of a switching device . 62
Figure 5 – Test sequence for polarity reversal tests . 65
Figure 6 – Diagram of a test circuit for the radio interference voltage test . 81
Figure 7 – Test location of radiation survey instrument . 90
Figure A.1 – Example of HVDC side switchgear arrangement for one pole in an HVDC
substation . 107
Figure D.1 – VSC HVDC under worst-case, pole-pole DC fault . 110
Figure D.2 – LCC HVDC under worst-case, pole-pole DC fault . 111
Figure D.3 – Special case LCC HVDC under worst-case, pole-pole DC fault . 112
Figure D.4 – HVDC system with DC circuit-breaker under worst-case, pole-pole DC

fault 113
Figure D.5 – DC circuit-breaker simple model . 113
Figure D.6 – Equivalent fault current for calculation of rated short time withstand direct
current . 114
Figure G.1 – Arrangement for weatherproofing test . 121
Figure G.2 – Nozzle for weatherproofing test . 122
Figure K.1 – Test circuit for superimposed impulse tests using blocking capacitor . 130
Figure K.2 – Test circuit for superimposed impulse tests using sphere gap . 131

Table 1 – Preferred rated insulation levels . 38
Table 2 – Direct voltage of auxiliary and control circuits . 44
Table 3 – Alternating voltage of auxiliary and control circuits . 44
Table 4 – Auxiliary contact classes . 49
Table 5 – Nameplate information . 54
Table 6 – Test conditions in general case . 62

– 8 – IEC TS 62271-5:2024 © IEC 2024
Table 7 – Test conditions in case of impulse voltage tests across the isolating distance
(or open switching device) . 62
Table 8 – Test conditions in case of superimposed impulse voltage tests . 63
Table 9 – Test conditions for polarity reversal tests . 65
Table 10 – Limits of temperature and temperature rise for various parts, materials and

dielectrics of high-voltage switchgear and controlgear . 71
Table 11 – Permissible leakage rates for gas systems . 78
Table 12 – Application of voltages at the fast transient/burst test . 83
Table 13 – Application of voltage at the damped oscillatory wave test. 84
Table 14 – Assessment criteria for transient disturbance immunity. 85
Table C.1 – Preferred insulation levels for rated voltages lower than 105 kV . 109
Table E.1 – List of reference documents for auxiliary and control circuit components . 116
Table H.1 – Tolerances on test quantities for type test . 123
Table J.1 Drawing list and contents . 128

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 5: Common specifications for direct current
switchgear and controlgear
FOREWORD
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC TS 62271-5 has been prepared by IEC technical committee 17: High-voltage switchgear
and controlgear. It is a Technical Specification.
The text of this document is based on the following documents:
Draft Report on voting
17/1136/DTS 17/1143B/RVDTS
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 document is English.

– 10 – IEC TS 62271-5:2024 © IEC 2024
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.
The list of all parts of the IEC 62271 series under the general title, High-voltage switchgear and
controlgear, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under “http://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
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INTRODUCTION
This Technical Specification has been prepared by TC 17 and it defines common specifications
for high-voltage direct current (HVDC) switchgear and controlgear covering both types of air
insulated (AIS) and gas insulated (GIS) equipment of HVDC substations. This document
includes rules for service conditions, ratings, design and construction requirements. Test
requirements and criteria to proof for passing type and routine tests are defined in this document
for development and manufacturing of HVDC switchgear.
This specification is applicable for both LCC and VSC HVDC technology.
SC 17A is in the process of preparing documents for the following HVDC switching devices:
– circuit-breakers (IEC TS 62271-313 [1]) ;
– disconnectors and earthing switches (IEC TS 62271-314 [2]);
– transfer switches (IEC TS 62271-315 [3]);
– by-pass switches and paralleling switches (IEC TS 62271-316 [4]).
SC 17C is in the process of preparing a document for DC gas insulated switchgears (IEC TS
62271-318 [5]).
Standardization of direct voltages is the responsibility of TC 8 (System aspects of electrical
energy supply).
TC 99 (Insulation co-ordination and system engineering of high voltage electrical power
installations above 1,0 kV AC and 1,5 kV DC) defines requirements of DC substations for safety
of insulation, equipment, installation and earthing (IEC 61936-2).
TC 115 (High Voltage Direct Current (HVDC) transmission for DC voltages above 100 kV) is
responsible for DC transmission system aspects. It is the responsibility of TC 115 to define
...