IEC 62271-202:2022

IEC 62271-202 ®
Edition 3.0 2022-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
High-voltage switchgear and controlgear –
Part 202: AC prefabricated substations for rated voltages above 1 kV and up to
and including 52 kV
Appareillage à haute tension –
Partie 202: Postes préfabriqués pour courant alternatif de tensions assignées
supérieures à 1 kV et inférieures ou égales à 52 kV
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IEC 62271-202 ®
Edition 3.0 2022-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
High-voltage switchgear and controlgear –

Part 202: AC prefabricated substations for rated voltages above 1 kV and up to

and including 52 kV
Appareillage à haute tension –

Partie 202 : Postes préfabriqués pour courant alternatif de tensions assignées

supérieures à 1 kV et inférieures ou égales à 52 kV

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.10 ISBN 978-2-8322-1609-5

– 2 – IEC 62271-202:2022 © IEC 2022
CONTENTS
FOREWORD . 9
INTRODUCTION . 11
1 Scope . 12
2 Normative references . 13
3 Terms and definitions . 15
3.1 General terms and definitions . 15
3.2 Assemblies of switchgear and controlgear . 15
3.3 Parts of assemblies . 15
3.4 Switching devices . 16
3.5 Parts of switchgear and controlgear . 17
3.6 Operational characteristics of switchgear and controlgear . 17
3.7 Characteristic quantities . 18
3.8 Index of definitions . 18
4 Normal and special service conditions . 18
4.1 Normal service conditions . 18
4.1.1 General . 18
4.1.2 Indoor switchgear and controlgear . 19
4.1.3 Outdoor switchgear and controlgear . 19
4.1.101 Low-voltage switchgear and controlgear . 19
4.1.102 Power transformer . 19
4.2 Special service conditions . 20
4.2.1 General . 20
4.2.2 Altitude . 20
4.2.3 Exposure to pollution . 20
4.2.4 Temperature and humidity . 21
4.2.5 Exposure to abnormal vibrations, shock or tilting . 21
4.2.6 Wind speed . 21
4.2.7 Other parameters . 21
5 Ratings . 21
5.1 General . 21
5.2 Rated voltage (U ) . 22
r
5.3 Rated insulation level (U , U , U ) . 22
d p s
5.4 Rated frequency (f ) . 23
r
5.5 Rated continuous current (I ) . 23
r
5.6 Rated short-time withstand current (I ) . 23
k
5.6.101 Rated short-time withstand current of high-voltage switchgear and
controlgear and high-voltage interconnection (I ) . 23
k
5.6.102 Rated short-time phase to earth withstand current (I ) . 24
ke
5.6.103 Rated short-time withstand currents of low-voltage switchgear and
controlgear and low-voltage interconnection (I ) . 24
cw
5.7 Rated peak withstand current (I ) . 24
p
5.7.101 Rated peak phase to earth withstand current (I ) . 24
pe
5.7.102 Rated peak withstand currents of low-voltage switchgear and
controlgear and low-voltage interconnection (I ) . 24
pk
5.8 Rated duration of short-circuit (t ) . 24
k
5.8.101 Rated duration of short-circuit (t ) . 25
k
5.8.102 Rated duration of phase to earth short-circuit (t ) . 25
ke
5.8.103 Rated duration of short-circuits for low-voltage switchgear and
controlgear and low-voltage interconnection . 25
5.8.104 Rated duration of short-circuits for power transformers . 25
5.9 Rated supply voltage of auxiliary and control circuits (U ) . 25
a
5.10 Rated supply frequency of auxiliary and control circuits . 25
5.11 Rated pressure of compressed gas supply for controlled pressure systems . 25
5.101 Rated power of prefabricated substation and class of enclosure . 25
5.101.1 Rated power of the prefabricated substation . 25
5.101.2 Rated class of enclosure . 26
5.102 Ratings of the internal arc classification (IAC) . 26
5.102.1 General . 26
5.102.2 Types of accessibility (A, B, AB) . 26
5.102.3 Rated arc fault currents (I , I ) . 27
A Ae
5.102.4 Rated arc fault duration (t , t ) . 27
A Ae
6 Design and construction . 27
6.1 Requirements for liquids in switchgear and controlgear . 28
6.2 Requirements for gases in switchgear and controlgear . 28
6.3 Earthing of switchgear and controlgear . 28
6.4 Auxiliary and control equipment and circuits . 29
6.4.1 General . 29
6.4.2 Protection against electric shock . 29
6.4.3 Components installed in enclosures . 30
6.5 Dependent power operation . 30
6.6 Stored energy operation . 30
6.7 Independent unlatched operation (independent manual or power operation) . 31
6.8 Manually operated actuators . 31
6.9 Operation of releases . 31
6.10 Pressure/level indication . 31
6.11 Nameplates. 31
6.12 Locking devices . 31
6.13 Position indication . 31
6.14 Degrees of protection provided by enclosures . 31
6.15 Creepage distances for outdoor insulators . 32
6.16 Gas and vacuum tightness . 32
6.17 Tightness for liquid systems . 32
6.18 Fire hazard (flammability) . 32
6.19 Electromagnetic compatibility (EMC) . 32
6.20 X-ray emission . 32
6.21 Corrosion . 32
6.22 Filling levels for insulation, switching and/or operation . 32
6.101 Protection of the prefabricated substation against mechanical stress . 33
6.102 Protection of the environment due to internal defects . 33
6.103 Internal arc fault . 34
6.104 Enclosure . 34
6.104.1 General . 34
6.104.2 Fire behaviour . 35

– 4 – IEC 62271-202:2022 © IEC 2022
6.104.3 Environmental considerations . 36
6.104.4 Covers and doors . 36
6.104.5 Ventilation openings . 37
6.104.6 Partitions . 37
6.105 Other provisions. 37
6.105.1 Provisions for dielectric tests on cables . 37
6.105.2 Accessories . 37
6.105.3 Operation aisle . 38
6.105.4 Labels . 38
6.105.5 Provisions for on-site assembly of prefabricated substation . 38
6.106 Sound emission . 38
6.107 Electromagnetic fields . 38
6.108 Solar radiation . 38
7 Type tests . 39
7.1 General . 39
7.1.1 Basics . 39
7.1.2 Information for identification of test objects . 40
7.1.3 Information to be included in type-test reports . 40
7.2 Dielectric tests . 40
7.2.1 General . 40
7.2.2 Ambient air conditions during tests . 41
7.2.3 Wet test procedure . 41
7.2.4 Arrangement of the equipment . 41
7.2.5 Criteria to pass the test . 41
7.2.6 Application of the test voltage and test conditions . 41
7.2.7 Tests of switchgear and controlgear of U ≤ 245 kV . 41
r
7.2.8 Tests of switchgear and controlgear of U > 245 kV . 41
r
7.2.9 Artificial pollution tests for outdoor insulators . 41
7.2.10 Partial discharge tests . 41
7.2.11 Dielectric tests on auxiliary and control circuits . 41
7.2.12 Voltage test as condition check . 42
7.2.101 Tests on the high-voltage components . 42
7.2.102 Tests on low-voltage interconnection . 43
7.3 Radio interference voltage (RIV) test . 44
7.4 Resistance measurement . 44
7.4.1 Measurement of the resistance of auxiliary contacts class 1 and class 2. 44
7.4.2 Measurement of the resistance of auxiliary contacts class 3 . 44
7.4.3 Electrical continuity of earthed metallic parts test . 44
7.4.4 Resistance measurement of contacts and connections in the main
circuit as a condition check . 45
7.5 Continuous current tests . 45
7.5.101 General . 45
7.5.102 Test conditions . 46
7.5.103 Test methods . 47
7.5.104 Measurements . 51
7.5.105 Acceptance criteria . 53
7.5.106 Continuous current test under solar radiation . 54
7.6 Short-time withstand current and peak withstand current tests . 54
7.7 Verification of the protection . 55

7.8 Tightness tests . 55
7.9 Electromagnetic compatibility tests (EMC) . 55
7.10 Additional tests on auxiliary and control circuits . 55
7.10.1 General . 55
7.10.2 Functional tests . 55
7.10.3 Verification of the operational characteristics of auxiliary contacts . 56
7.10.4 Environmental tests . 56
7.10.5 Dielectric test . 56
7.11 X-radiation test for vacuum interrupters . 56
7.101 Calculations and mechanical tests . 56
7.101.1 Wind pressure . 56
7.101.2 Roof loads . 56
7.101.3 Mechanical impacts . 56
7.101.4 Handling . 56
7.102 Internal arc test . 57
7.102.1 General . 57
7.102.2 Test conditions . 57
7.102.3 Arrangement of the equipment . 58
7.102.4 Test procedure . 58
7.102.5 Criteria to pass the test . 58
7.102.6 Test report . 60
7.102.7 Transferability of tests results . 60
7.103 Measurement or calculation of electromagnetic fields . 61
8 Routine tests . 61
8.1 General . 61
8.2 Dielectric test on the main circuit . 61
8.3 Test on auxiliary and control circuits . 61
8.3.1 Inspection of auxiliary and control circuits, and verification of conformity
to the circuit diagrams and wiring diagrams . 61
8.3.2 Functional tests . 61
8.3.3 Verification of protection against electric shock . 61
8.3.4 Dielectric tests . 62
8.4 Measurement of the resistance of the main circuit . 62
8.5 Tightness test . 62
8.6 Design and visual checks . 62
8.101 Other functional tests . 62
8.102 Tests after assembly on site . 62
9 Guide to the selection of switchgear and controlgear (informative) . 62
9.101 General . 62
9.102 Selection of rated values . 63
9.103 Selection of class of enclosure . 63
9.104 Internal arc fault . 64
9.104.1 General . 64
9.104.2 Causes and preventive measures . 64
9.104.3 Supplementary protective measures . 64
9.104.4 Considerations for the selection and installation . 66
9.104.5 IAC classification . 66
9.105 Summary of technical requirements and ratings . 67
10 Information to be given with enquiries, tenders and orders (informative) . 73

– 6 – IEC 62271-202:2022 © IEC 2022
10.1 General . 73
10.2 Information with enquiries and orders . 73
10.3 Information with tenders . 74
11 Transport, storage, installation, operating instructions and maintenance. 74
11.1 General . 74
11.2 Conditions during transport, storage and installation . 75
11.3 Installation . 75
11.3.1 General . 75
11.3.2 Unpacking and lifting . 75
11.3.3 Assembly . 75
11.3.4 Mounting . 75
11.3.5 Connections . 76
11.3.6 Information about gas and gas mixtures for controlled and closed
pressure systems . 76
11.3.7 Final installation inspection . 76
11.3.8 Basic input data by the user . 76
11.3.9 Basic input data by the manufacturer . 76
11.4 Operating instructions . 76
11.5 Maintenance . 76
12 Safety . 77
12.101 General . 77
12.102 Electrical aspects . 77
12.103 Mechanical aspects . 77
12.104 Thermal aspects . 77
12.105 Internal arc aspects . 77
13 Influence of the product on the environment . 77
Annex A (normative) Internal arc fault – Method to verify the internal arc classification
(IAC) . 78
A.1 General . 78
A.2 Room simulation . 78
A.3 Indicators (for assessing the thermal effects of the gases) . 78
A.3.1 General . 78
A.3.2 Arrangement of indicators . 80
A.4 Tolerances for geometrical dimensions of test arrangements . 86
A.5 Test parameters . 86
A.6 Test procedure . 87
Annex B (normative) Test to verify the sound level of a high-voltage/low-voltage
transformer prefabricated substation . 92
B.1 Purpose . 92
B.2 Test object . 92
B.3 Test method . 92
B.4 Measurements . 92
B.5 Presentation and calculation of the results . 92
Annex C (normative) Mechanical impact test. 94
C.1 Test for the verification of the resistance to mechanical impact . 94
C.2 Apparatus for the verification of the protection against mechanical damage . 94
Annex D (informative) Rating of power transformers in an enclosure. 96
D.1 General . 96
D.2 Mineral-oil-immersed power transformer . 96

D.3 Dry-type power transformer . 97
D.4 Example. 101
Annex E (informative) Examples of earthing arrangements . 104
Annex F (informative) Characteristics of enclosure materials . 107
F.1 Metals . 107
F.1.1 Coatings . 107
F.1.2 Paints . 107
F.2 Concrete . 107
Annex G (informative) Evaluation of the impact of solar radiation – Simulated solar
radiation continuous current test . 109
G.1 General . 109
G.2 Test method . 109
G.2.1 General . 109
G.2.2 Test parameters, equipment and preparation . 109
G.2.3 Test procedure and application of test currents. 111
G.2.4 Measurements . 111
G.3 Evaluation of the solar radiation effects . 112
G.3.1 Evaluation of solar radiation effects on the temperature rise of power
transformer . 112
G.3.2 Evaluation of solar radiation effects on the temperature rise of
components other than the power transformer . 112
G.4 Application considerations . 112
Annex H (informative) Installation conditions of electronic equipment . 114
H.1 General . 114
H.2 Accessibility . 114
H.3 Application of air temperature measurements inside the prefabricated
substation . 115
Bibliography . 116

Figure 1 – Measurement of power transformer temperature rise in ambient air: ∆t . 46
Figure 2 – Measurement of power transformer temperature rise in an enclosure: ∆t . 46
Figure 3 – Diagram of the preferred continuous current test method . 48
Figure 4 – Diagram of the continuous current test alternative method . 49
Figure 5 – Diagram for open-circuit test . 50
Figure 6 – Example of air temperature measurement locations inside a non-walk-in
type prefabricated substation . 53
Figure A.1 – Mounting frame for vertical indicators . 79
Figure A.2 – Horizontal indicators . 79
Figure A.3 – Arrangement of indicators . 86
Figure A.4 – Selection of tests on high-voltage switchgear and controlgear for
class IAC-A . 87
Figure A.5 – Selection of tests on high-voltage switchgear and controlgear for
class IAC-B . 88
Figure A.6 – Selection of tests on high-voltage interconnections for class IAC-A. 89
Figure A.7 – Selection of tests on high-voltage interconnections for class IAC-B. 90
Figure C.1 – Impact test apparatus . 95

– 8 – IEC 62271-202:2022 © IEC 2022
Figure D.1 – Mineral-oil-immersed power transformer load factor inside of the
enclosure related to ambient air at the location and top-oil and winding temperature
rise limits . 97
Figure D.2 – Dry-type power transformer load factor outside of the enclosure . 97
Figure D.3 – Insulation class 105 °C (A) dry-type power transformers load factor in an
enclosure . 98
Figure D.4 – Insulation class 120 °C (E) dry-type power transformers load factor in an
enclosure . 99
Figure D.5 – Insulation class 130 °C (B) dry-type power transformers load factor in an
enclosure . 99
Figure D.6 – Insulation class 155 °C (F) dry-type power transformers load factor in an
enclosure . 100
Figure D.7 – Insulation class 180 °C (H) dry-type power transformers load factor in an
enclosure . 100
Figure D.8 – Insulation class 200 °C (H) dry-type power transformers load factor in an
enclosure . 101
Figure D.9 – Insulation class 220 °C (H) dry-type power transformers load factor in an
enclosure . 101
Figure E.1 – Example of earthing arrangement . 104
Figure E.2 – Example of earthing arrangement . 105
Figure E.3 – Example with the framework serving as part of the main earthing
conductor . 106
Figure G.1 – Indicative arrangement of laboratory radiation sources (e.g. radiant heat
lamps) for continuous current test with simulated solar radiation . 110

Table 1 – Synthetic material characteristics . 35
Table 2 – Type tests . 40
Table 3 – Locations, causes and examples of measures decreasing the probability of
internal arcs . 65
Table 4 – Single phase-to-earth arc fault current depending on the network neutral
earthing . 67
Table 5 – Summary of technical requirements, characteristics and ratings relevant for
prefabricated substations . 68
Table F.1 – Treatment of coatings . 107
Table F.2 – Tests of coatings . 107
Table F.3 – Test of concrete . 108

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 202: AC prefabricated substations for rated voltages above 1 kV and
up to and including 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. Internatio
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