IEC 62271-202:2014

IEC 62271-202 ®
Edition 2.0 2014-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
High-voltage switchgear and controlgear –
Part 202: High-voltage/low-voltage prefabricated substation

Appareillage à haute tension –
Partie 202: Postes préfabriqués haute tension/basse tension

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IEC 62271-202 ®
Edition 2.0 2014-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
High-voltage switchgear and controlgear –

Part 202: High-voltage/low-voltage prefabricated substation

Appareillage à haute tension –

Partie 202: Postes préfabriqués haute tension/basse tension

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XD
ICS 29.130.10 ISBN 978-2-8322-1483-1

– 2 – IEC 62271-202:2014 © IEC 2014
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 General . 11
1.1 Scope . 11
1.2 Normative references . 11
2 Normal and special service conditions . 13
2.1 Normal service conditions . 13
2.1.1 Indoor switchgear and controlgear . 13
2.1.1.101 Low-voltage switchgear and controlgear . 13
2.1.1.102 Transformer . 13
2.1.2 Outdoor switchgear and controlgear . 14
2.2 Special service conditions . 14
2.2.1 Altitude . 14
2.2.2 Pollution . 14
2.2.3 Temperature and humidity . 15
2.2.4 Vibrations, shock or tilting. 15
2.2.5 Wind speed . 15
2.2.6 Other parameters . 15
3 Terms and definitions . 15
4 Ratings . 17
4.1 Rated voltage (U ) . 18
r
4.2 Rated insulation level . 18
4.3 Rated frequency (f ) . 19
r
4.4 Rated normal current and temperature rise . 19
4.4.1 Rated normal current (I ) . 19
r
4.4.2 Temperature rise . 19
4.4.3 Particular points of Table 3 . 19
4.5 Rated short-time withstand current (I ) . 19
k
4.5.101 Rated short-time withstand current of high voltage switchgear
and controlgear and high voltage interconnection (I ) . 20
k
4.5.102 Rated short-time phase to earth withstand current (I ) . 20
ke
4.5.103 Rated short-time withstand currents of low voltage switchgear
and controlgear and low voltage interconnection (I ) . 20
cw
4.6 Rated peak withstand current (I ) . 20
p
4.6.101 Rated peak withstand current (I ) . 20
p
4.6.102 Rated peak phase to earth withstand current (I ) . 20
pe
4.6.103 Rated peak withstand currents of low voltage switchgear and
controlgear and low voltage interconnection (I ) . 20
pk
4.7 Rated durations of short circuit (t ) . 20
k
4.7.101 Rated duration of short circuit (t ) . 21
k
4.7.102 Rated duration of phase to earth short circuit (t ) . 21
ke
4.7.103 Rated duration of short circuits for low voltage switchgear and
controlgear and low voltage interconnection . 21
4.7.104 Rated duration of short circuits for transformers . 21
4.8 Rated supply voltage of closing and opening devices and auxiliary and
control circuits (U ) . 21
a
4.9 Rated supply frequency of closing and opening devices and of auxiliary
circuits . 21

4.10 Rated pressure of compressed gas supply for controlled pressure
systems . 21
4.11 Rated filling levels for insulation and/or operation . 21
4.101 Rated maximum power and class of enclosure . 22
4.101.1 Rated maximum power of the prefabricated substation . 22
4.101.2 Rated class of enclosure . 22
4.102 Ratings of the internal arc classification . 22
4.102.1 General . 22
4.102.2 Types of accessibility (A, B, AB) . 22
4.102.3 Rated arc fault currents (I , I ) . 22
A Ae
4.102.4 Rated arc fault duration (t , t ) . 23
A Ae
5 Design and construction . 23
5.1 Requirements for liquids in switchgear and controlgear . 23
5.2 Requirements for gases in switchgear and controlgear . 23
5.3 Earthing of switchgear and controlgear . 24
5.4 Auxiliary and control equipment . 25
5.5 Dependent power operation . 25
5.6 Stored energy operation . 25
5.7 Independent manual or power operation (independent unlatched
operation) . 25
5.8 Operation of releases . 25
5.9 Low- and high-pressure interlocking and monitoring devices . 25
5.10 Nameplates. 25
5.11 Interlocking devices . 25
5.12 Position indication . 26
5.13 Degree of protection provided by enclosures . 26
5.14 Creepage distances for outdoor insulators . 26
5.15 Gas and vacuum tightness . 26
5.16 Liquid tightness . 26
5.17 Fire hazard (flammability) . 26
5.18 Electromagnetic compatibility (EMC) . 26
5.101 Protection of the prefabricated substation against mechanical stress . 26
5.102 Protection of the environment due to internal defects . 27
5.103 Internal arc fault . 27
5.104 Enclosure . 28
5.104.1 General . 28
5.104.2 Fire behaviour . 28
5.104.3 Corrosion . 29
5.104.4 Covers and doors . 30
5.104.5 Ventilation openings . 30
5.104.6 Partitions . 30
5.105 Other provisions. 31
5.105.1 Provisions for dielectric tests on cables . 31
5.105.2 Accessories . 31
5.105.3 Operation aisle . 31
5.105.4 Labels . 31
5.106 Sound emission . 31
5.107 Electromagnetic fields . 31
6 Type tests . 31

– 4 – IEC 62271-202:2014 © IEC 2014
6.1 General . 31
6.1.1 Grouping of tests . 32
6.1.2 Information for identification of specimens . 32
6.1.3 Information to be included in type-test reports . 32
6.2 Dielectric tests . 33
6.2.1 Ambient air conditions during tests . 33
6.2.2 Wet test procedure . 33
6.2.3 Conditions of switchgear and controlgear during dielectric
tests . 33
6.2.4 Criteria to pass the test . 33
6.2.5 Application of the test voltage and test conditions . 33
6.2.6 Tests of switchgear and controlgear of U ≤ 245 kV . 33
r
6.2.7 Tests of switchgear and controlgear of U > 245 kV . 33
r
6.2.8 Artificial pollution tests for outdoor insulators . 33
6.2.9 Partial discharge tests . 33
6.2.10 Dielectric tests on auxiliary and control circuits. . 34
6.2.11 Voltage test as condition check . 34
6.2.101 Tests on the high-voltage interconnection . 34
6.2.102 Tests on low-voltage interconnection . 35
6.3 Radio interference voltage (r.i.v.) test . 36
6.4 Measurement of the resistance of circuits . 36
6.5 Temperature-rise tests . 36
6.5.101 General . 36
6.5.102 Test conditions . 37
6.5.103 Test methods . 38
6.5.104 Measurements . 41
6.5.105 Acceptance criteria . 42
6.6 Short-time withstand current and peak withstand current tests . 43
6.7 Verification of the protection . 43
6.8 Tightness tests . 43
6.9 Electromagnetic compatibility tests (EMC) . 43
6.10 Additional tests on auxiliary and control circuits . 44
6.10.1 General . 44
6.10.2 Functional tests . 44
6.10.3 Electrical continuity of earthed metallic parts test . 44
6.10.4 Verification of the operational characteristics of auxiliary
contacts . 44
6.10.5 Environmental tests . 44
6.10.6 Dielectric test . 44
6.11 X-radiation test procedures for vacuum interrupters . 44
6.101 Calculations and mechanical tests . 44
6.101.1 Wind pressure . 44
6.101.2 Roof loads . 45
6.101.3 Mechanical impacts . 45
6.102 Internal arc test . 45
6.102.1 General . 45
6.102.2 Test conditions . 45
6.102.3 Arrangement of the equipment . 46
6.102.4 Test procedure . 46

6.102.5 Criteria to pass the test . 46
6.102.6 Test report . 47
6.102.7 Transferability of tests results . 48
6.103 Measurement or calculation of electromagnetic fields . 48
7 Routine tests . 48
Replacement: . 49
7.101 Dielectric test on the high voltage interconnection. 49
7.102 Voltage withstand tests on auxiliary circuits . 49
7.103 Functional tests . 49
7.104 Verification of correct wiring . 49
7.105 Tests after assembly on site . 49
8 Guide to the selection of prefabricated substation . 49
Replacement: . 49
8.101 General . 49
8.102 Selection of rated values . 50
8.103 Selection of class of enclosure . 50
8.104 Internal arc fault . 50
8.104.1 General . 50
8.104.2 Causes and preventive measures . 51
8.104.3 Supplementary protective measures . 51
8.104.4 Considerations for the selection and installation . 53
8.104.5 Internal arc test . 53
8.104.6 IAC classification . 53
8.105 Summary of technical requirements, ratings and optional tests . 54
9 Information to be given with enquiries, tenders and orders . 58
9.1 Information with enquiries and orders . 58
9.2 Information with tenders . 59
10 Transport, storage, installation, operation, maintenance . 60
10.1 Conditions during transport, storage and installation . 60
10.2 Installation . 60
10.2.1 Unpacking and lifting . 61
10.2.2 Assembly . 61
10.2.3 Mounting . 61
10.2.4 Connections . 61
10.2.5 Final installation inspection . 61
10.2.6 Basic input data by the user . 61
10.2.7 Basic input data by the manufacturer . 61
10.3 Operation . 61
10.4 Maintenance . 62
10.101 Dismantling, recycling and disposal at the end-of-service life . 62
11 Safety . 62
11.101 Electrical aspects . 62
11.102 Mechanical aspects . 62
11.103 Thermal aspects . 62
11.104 Internal arc aspects . 62
12 Influence of the product on the environment . 63
Annex AA (normative) Internal arc fault – Method to verify the internal arc
classification (IAC) . 64

– 6 – IEC 62271-202:2014 © IEC 2014
AA.1 General . 64
AA.2 Room simulation . 64
AA.3 Indicators (for assessing the thermal effects of the gases) . 64
AA.3.1 General . 64
AA.3.2 Arrangement of indicators . 65
AA.4 Tolerances for geometrical dimensions of test arrangements . 66
AA.5 Test parameters . 67
AA.6 Test procedure . 67
Annex BB (normative) Test to verify the sound level of a prefabricated substation . 76
BB.1 Purpose . 76
BB.2 Test specimen . 76
BB.3 Test method . 76
BB.4 Measurements . 76
BB.5 Presentation and calculation of the results . 76
Annex CC (normative) Mechanical impact test . 78
CC.1 Test for the verification of the resistance to mechanical impact . 78
CC.2 Apparatus for the verification of the protection against mechanical
damage. 78
Annex DD (informative)  Rating of transformers in an enclosure . 80
DD.1 General . 80
DD.2 Liquid-filled transformer . 80
DD.3 Dry-type transformer . 81
DD.4 Example. 85
Annex EE (informative) Examples of earthing circuits . 88
Annex FF (informative) Characteristics of enclosure materials . 91
FF.1 Metals . 91
FF.1.1 Coatings . 91
FF.1.2 Paints . 91
FF.2 Concrete . 91
Bibliography . 93

Figure 101 – Measurement of transformer temperature rise in ambient air: ∆t . 37
Figure 102 – Measurement of transformer temperature rise in an enclosure: ∆t . 37
Figure 103 – Diagram of the preferred temperature-rise test method . 39
Figure 104 – Diagram of the alternative temperature-rise test method . 40
Figure 105 – Diagram for open-circuit test . 41
Figure AA.1 – Mounting frame for vertical indicators . 68
Figure AA.2 – Horizontal indicators . 68
Figure AA.3 – Arrangement of indicators . 71
Figure AA.4 – Selection of tests on high voltage switchgear for class IAC-A . 72
Figure AA.5 – Selection of tests on high voltage switchgear for class IAC-B . 73
Figure AA.6 – Selection of tests on high voltage interconnections for class IAC-A . 74
Figure AA.7 – Selection of tests on high voltage interconnections for class IAC-B . 75
Figure CC.1 – Impact test apparatus . 79
Figure DD.1 – Liquid-filled transformer load factor in an enclosure . 81
Figure DD.2 – Dry-type transformer load factor outside of the enclosure . 81

Figure DD.3 – Insulation class 105 °C (A) dry-type transformers load factor in an
enclosure . 82
Figure DD.4 – Insulation class 120 °C (E) dry-type transformers load factor in an
enclosure . 82
Figure DD.5 – Insulation class 130 °C (B) dry-type transformers load factor in an
enclosure . 83
Figure DD.6 – Insulation class 155 °C (F) dry-type transformers load factor in an
enclosure . 83
Figure DD.7 – Insulation class 180 °C (H) dry-type transformers load factor in an
enclosure . 84
Figure DD.8 – Insulation class 200 °C (H) dry-type transformers load factor in an
enclosure . 84
Figure DD.9 – Insulation class 220 °C (H) dry-type transformers load factor in an
enclosure . 85
Figure EE.1 – Example of earthing circuits . 88
Figure EE.2 – Example of earthing circuits . 89
Figure EE.3 – Example within the framework serving as the main earthing conductor . 90

Table 101 – Synthetic material characteristics . 29
Table 102 – Locations, causes and examples of measures decreasing the probability
of internal arcs . 52
Table 103 – Single phase-to-earth arc fault current depending on the network neutral
earthing . 54
Table 104 – Summary of technical requirements and ratings for prefabricated
substations (1 of 4) . 55
Table FF.1 – Treatment of coatings . 91
Table FF.2 – Tests of coatings . 91
Table FF.3 – Test of concrete . 92

– 8 – IEC 62271-202:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 202: High-voltage/low-voltage prefabricated substation

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62271-202 has been prepared by subcommittee 17C: High-voltage
switchgear and controlgear assemblies, of IEC technical committee 17: Switchgear and
controlgear.
This second edition cancels and replaces the first edition published in 2006. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) regarding temperature-rise test an alternative method for liquid filled transformers is
(re)introduced and the temperature-rise test method for dry-type transformers is specified
more precisely;
b) testing procedure for short time and peak withstand current tests are specified more
precisely;
c) assessment of electromagnetic fields is considered including a type test (optional)
according IEC/TR 62271-208:2009;

d) influence of the product on the environment is considered (Clause 12);
e) internal arc test requirements have been adapted to IEC 62271-200:2011 and
requirements for the assessment of pressure relief volumes below the floor / ground has
been assigned;
f) the method for defining the load factor in an enclosure for liquid filled transformers is
extended with different temperature rises for the transformer outside the enclosure
(Annex DD);
g) for the calculation of the load factor of dry-type transformers in an enclosure the insulation
systems according to IEC 60076-1:2011, Tables B.1 and B.2 are worked out in detail.
The text of this standard is based on the following documents:
FDIS Report on voting
17C/595/FDIS 17C/598/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This standard should be read in conjunction with IEC 62271-1:2007 and its Amendment
1:2011, to which it refers and which is applicable, unless otherwise specified. In order to
simplify the indication of corresponding requirements, the same numbering of clauses and
subclauses is used as in IEC 62271-1. Amendments to these clauses and subclauses are
given under the same numbering, whilst additional subclauses are numbered from 101.
A list of all parts of the IEC 62271 series can be found, under the general title High-voltage
switchgear and controlgear, on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
The contents of the corrigendum of April 2015 have been included in this copy.

IMPORTANT – The 'colour inside' logo on the cover page of this publication 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.
– 10 – IEC 62271-202:2014 © IEC 2014
INTRODUCTION
Prefabricated substations are defined as a type-tested assembly comprising an enclosure
containing in general transformers, low-voltage and high-voltage switchgear, connections and
auxiliary equipment to supply low-voltage energy from a high-voltage system or vice versa.
These substations are in locations accessible to the public and should ensure protection to
persons according to the specified service conditions.
This means that, in addition to the specified characteristics, ratings and relevant test
procedures, particular attention has been paid to the specification concerning the protection
of persons, both operators and general public. Use of type-tested components and suitable
design and construction of the enclosure ensure this protection. The correct design and
performance of the prefabricated substation are verified by means of relevant type tests
described in this standard, including internal arc tests.

HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 202: High-voltage/low-voltage prefabricated substation

1 General
1.1 Scope
This part of IEC 62271 specifies the service conditions, rated characteristics, general
structural requirements and test methods of high voltage/low voltage or low voltage/high
voltage prefabricated substations, which are cable-connected, to be operated from inside
(walk-in type) or outside (non-walk-in type) for alternating current of rated voltages above
1 kV and up to and including 52 kV on the high voltage side, and for one or more transformers
for service frequencies up to and including 60 Hz for outdoor installation at locations with
public accessibility and where protection of personnel is provided.
Prefabricated substations can be situated at ground level or
...