IEC 62271-107:2019

IEC 62271-107 ®
Edition 3.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage switchgear and controlgear –
Part 107: Alternating current fused circuit-switchers for rated voltages
above 1 kV up to and including 52 kV

Appareillage à haute tension –
Partie 107: Circuits-switchers à fusibles pour courant alternatif de tension
assignée supérieure à 1 kV et jusqu'à 52 kV inclus
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IEC 62271-107 ®
Edition 3.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage switchgear and controlgear –

Part 107: Alternating current fused circuit-switchers for rated voltages

above 1 kV up to and including 52 kV

Appareillage à haute tension –

Partie 107: Circuits-switchers à fusibles pour courant alternatif de tension

assignée supérieure à 1 kV et jusqu'à 52 kV inclus

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.10 ISBN 978-2-8322-6924-4

– 2 – IEC 62271-107:2019 © IEC 2019
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
3.1 General terms and definitions . 10
3.2 Assemblies of switchgear and controlgear . 10
3.3 Parts of assemblies . 10
3.4 Switching devices . 10
3.5 Parts of switchgear and controlgear . 10
3.6 Operational characteristics of switchgear and controlgear . 11
3.7 Characteristic quantities . 11
3.101 Fuses . 14
4 Normal and special service conditions . 14
5 Ratings . 15
5.1 General . 15
5.2 Rated voltage (U ) . 15
r
5.3 Rated insulation level (U , U , U ) . 15
d p s
5.4 Rated frequency (f ) . 15
r
5.5 Rated continuous current (I ) . 15
r
5.6 Rated short-time withstand current (I ) . 15
k
5.7 Rated peak withstand current (I ) . 15
p
5.8 Rated duration of short-circuit (t ) . 16
k
5.9 Rated supply voltage of auxiliary and control circuits (U ) . 16
a
5.10 Rated supply frequency of auxiliary and control circuits . 16
5.11 Rated pressure of compressed gas supply for controlled pressure systems . 16
5.101 Rated short-circuit breaking current (I ) . 16
sc
5.102 Rated short-circuit making current (I ) . 16
ma
5.103 Rated take-over current (I ) . 17
to
6 Design and construction . 18
6.1 Requirements for liquids in fused circuit-switchers . 18
6.2 Requirements for gases in fused circuit-switchers . 18
6.3 Earthing of fused circuit-switchers . 18
6.4 Auxiliary and control equipment and circuits . 18
6.5 Dependent power operation . 18
6.6 Stored energy operation. 18
6.7 Independent unlatched operation (independent manual or power operation) . 18
6.8 Manually operated actuators . 18
6.9 Operation of releases. 18
6.10 Pressure/level indication . 18
6.11 Nameplates . 18
6.12 Locking devices . 20
6.13 Position indication . 20

6.14 Degrees of protection provided by enclosures . 20
6.15 Creepage distances for outdoor insulators . 20
6.16 Gas and vacuum tightness . 20
6.17 Tightness for liquid systems . 20
6.18 Fire hazard (flammability) . 20
6.19 Electromagnetic compatibility (EMC) . 20
6.20 X-ray emission . 20
6.21 Corrosion . 21
6.22 Filling levels for insulation, switching and/or operation . 21
6.101 Basic requirements for fuses . 21
6.102 Linkages between the fuse striker(s) and the circuit-switcher release . 21
6.103 Low over-current conditions (long fuse-pre-arcing time conditions) . 21
6.104 Rated continuous current values . 21
7 Type tests . 22
7.1 General . 22
7.2 Dielectric tests . 22
7.3 Radio interference voltage (RIV) test . 22
7.4 Resistance measurement . 22
7.5 Continuous current tests . 22
7.6 Short-time withstand current and peak withstand current tests . 22
7.7 Verification of the protection . 22
7.8 Tightness tests . 23
7.9 Electromagnetic compatibility tests (EMC) . 23
7.10 Additional tests on auxiliary and control circuits . 23
7.11 X-radiation test for vacuum interrupters . 23
7.101 Making and breaking tests . 23
7.101.1 General . 23
7.101.2 Conditions for performing the tests . 23
7.101.3 Test duty procedures . 29
7.101.4 Behaviour of the fused circuit-switcher during tests . 35
7.101.5 Condition of the apparatus after tests . 35
7.102 Mechanical operation tests . 36
7.102.1 General . 36
7.102.2 Test procedure . 36
7.102.3 Condition of fused circuit-switcher during and after mechanical
operation tests . 37
7.102.4 Condition of the fuses during and after mechanical operation tests . 37
7.103 Extension of validity of type tests . 37
7.103.1 General . 37
7.103.2 Dielectric properties . 38
7.103.3 Continuous current tests . 38
7.103.4 Making and breaking . 38
8 Routine tests . 38
8.1 General . 38
8.2 Dielectric test on the main circuit . 38
8.3 Tests on auxiliary and control circuits . 38
8.4 Measurement of the resistance of the main circuit . 39
8.5 Tightness test . 39
8.6 Design and visual checks . 39

– 4 – IEC 62271-107:2019 © IEC 2019
8.101 Mechanical operating tests . 39
9 Guide to the selection of fused circuit-switchers (informative) . 40
9.1 General . 40
9.2 Selection of rated values . 40
9.3 Cable interface consideration . 40
9.4 Continuous or temporary overload due to changed service conditions . 40
9.5 Environmental aspects . 40
9.101 Additional criteria . 40
9.102 Rated short-circuit breaking current . 41
9.103 Rated continuous current . 41
9.104 Currents between rated continuous current and I of the fuses . 41
9.105 Transfer current . 41
9.106 Take-over current . 41
9.107 Extension of the validity of type tests . 42
9.108 Operation . 42
9.109 Comparison of performances of fused circuit-switchers with performances of
switch-fuse combinations and circuit-breakers . 43
10 Information to be given with enquiries, tenders and orders (informative) . 43
10.1 General . 43
10.2 Information with enquiries and orders . 43
10.3 Information with tenders . 43
11 Transport, storage, installation, operating instructions and maintenance . 44
12 Safety . 44
13 Influence of the product on the environment . 44
Annex A (informative) Applicability of the rated take-over current test duty . 45
A.1 Problem formulation . 45
A.2 Background . 45
A.3 Terms, definitions and symbols . 46
A.4 Assumptions about the fuse melting process . 47
A.4.1 General . 47
A.4.2 First phase . 47
A.4.3 Second phase . 47
A.4.4 Modelling of the "application margin" . 48
A.5 Mathematical expression of the application requirements . 48
A.5.1 General . 48
A.5.2 First pole-to-clear . 48
A.5.3 Second pole-to-clear . 48
A.6 Analysis . 50
A.6.1 Applications with fuse strikers . 50
A.6.2 Applications with protection relays . 51
A.7 Conclusions . 52
Annex B (informative) Particular conditions existing in certain countries . 53
Bibliography . 54

Figure 1 – Characteristics for determining the take-over current . 17
Figure 2 – Arrangement of test circuits for test duties TD , TD , TD and TD . 26
Ir Isc Ito Ilow
Figure 3 – Representation of a specified TRV by a two-parameter reference line and a
delay line . 28
Figure 4 – Example of a two parameters envelope for a TRV . 29
Figure 5 – Measurement of the power frequency recovery voltage with striker operation . 31
Figure A.1 – Visualization of the application margin for a given fuse . 47

Table 1 – Nameplate information . 19
Table 2 – Summary of test parameters for test duties . 34
Table 3 – Comparison between switch-fuse combination and fused circuit-switcher . 43
Table 4 – Comparison between fused circuit-switcher and circuit breaker . 43
Table A.1 – Minimum application margin Am according to fuse characteristic . 51
Table A.2 – Minimum protection time delay . 51
Table A.3 – Examples of possible need for time delay . 52
Table B.1 – Voltages used in the Czech Republic . 53
Table B.2 – Rated insulation levels for voltage ratings of Table B.1 . 53

– 6 – IEC 62271-107:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 107: Alternating current fused circuit-switchers for
rated voltages above 1 kV 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
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agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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
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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.
International Standard IEC 62271-107 has been prepared by subcommittee 17A: Switching
devices, of IEC technical committee 17: High-voltage switchgear and controlgear
This third edition cancels and replaces the second edition published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) technical changes introduced by the second edition of IEC 62271-1 are applied, where
relevant;
b) rated TRV is removed and TRV is now treated as a test parameter, as in IEC 62271-100;
c) the term "thermal current" is no longer used; the rated continuous current is linked to the
installed fuse-links, and values shall be provided by the manufacturer together with the list
of the acceptable fuse-links; for tests purpose, the highest rated continuous current listed

is referred, where previously the wording was "rated maximum thermal current", for
consistency with IEC 62271-105;
d) making and breaking test duties are independent type tests (as some may be omitted if
and
the switching device has been validated as a load-break switch). However, TD
It0
TD are kept as a sequence as they are linked to the same rated value (I );
Ilow t0
e) differentiation has been introduced between requirements expressed for fulfilling the
function expected from a fused circuit-switcher, from requirements only relevant when the
function is performed by a stand-alone device. The goal is to avoid duplication or conflicts
of requirements with a standard dealing with assemblies, when the function is
implemented within such an assembly.
The text of this International Standard is based on the following documents:
FDIS Report on voting
17A/1216/FDIS 17A/1227/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
This International Standard is to be read in conjunction with IEC 62271-1:2017, 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.
Particular conditions existing in certain countries are listed in Annex B.
A list of all parts in the IEC 62271 series, published 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.
– 8 – IEC 62271-107:2019 © IEC 2019
INTRODUCTION
Earthing switches forming an integral part of a circuit-switcher are covered by
IEC 62271-102 [1] .
Installation in enclosure, if any, is covered either by IEC 62271-200 [2] or by
IEC 62271-201 [3].
______________
Numbers in square brackets refer to the Bibliography.

HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 107: Alternating current fused circuit-switchers for
rated voltages above 1 kV up to and including 52 kV

1 Scope
This part of IEC 62271 applies to three-pole-operated fused circuit-switchers designed with
rated voltages above 1 kV up to and including 52 kV for use on three-phase alternating
current systems of either 50 Hz or 60 Hz.
They can be designed either as stand-alone devices, or be embedded in a switchgear and
controlgear assembly.
They are intended to be used for circuits or applications requiring only a normal mechanical
and electrical endurance capability. Such applications cover protection of HV/LV transformers
for instance, but exclude distribution lines or cables, as well as motor circuits and capacitor
bank circuits.
Short-circuit conditions with low currents, up to the fused circuit-switcher rated take-over
current, are dealt with by supplementary devices (strikers, relays, etc.), properly arranged,
tripping the circuit-switcher. Current-limiting fuses are incorporated in order to ensure that the
short-circuit breaking capacity of the device is above that of the circuit-switcher alone.
NOTE 1 In this document, the term "fuse" is used to designate either the fuse or the fuse-link where the general
meaning of the text does not result in ambiguity.
NOTE 2 Other circuit-switchers exist; see reference [4].
Devices that require a dependent manual operation are not covered by this document.
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 60282-1:2009, High-voltage fuses – Part 1: Current-limiting fuses
IEC 60282-1:2009/AMD1:2014
IEC 62271-1:2017, High-voltage switchgear and controlgear – Part 1: Common specifications
IEC 62271-100:2008, High-voltage switchgear and controlgear – Part 100: Alternating-current
circuit-breakers
IEC 62271-100:2008/AMD1:2012
IEC 62271-100:2008/AMD2:2017
IEC 62271-103:2011, High-voltage switchgear and controlgear – Part 103: Switches for rated
voltages above 1 kV up to and including 52 kV
IEC 62271-105:2012, High-voltage switchgear and controlgear – Part 105: Alternating current
switch-fuse combinations for rated voltages above 1 kV up to and including 52 kV

– 10 – IEC 62271-107:2019 © IEC 2019
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
NOTE IEC Electropedia lists the terms defined in the IEC 60050 [5].
3.1 General terms and definitions
Subclause 3.1 of IEC 62271-1:2017 applies.
3.2 Assemblies of switchgear and controlgear
Subclause 3.2 of IEC 62271-1:2017 applies.
3.3 Parts of assemblies
Subclause 3.3 of IEC 62271-1:2017 applies.
3.4 Switching devices
Subclause 3.4 of IEC 62271-1:2017 applies, with the following additions.
3.4.101
circuit-switcher
mechanical switching device suitable for making, carrying and interrupting currents under
normal circuit conditions and for interrupting specified fault currents that are usually smaller
than its short-time withstand current
Note 1 to entry: Other circuit-switchers exist; see reference [4].
3.4.102
fused circuit-switcher
combination, in a single device or function, of a circuit-switcher and fuses, one fuse being
placed in series with each pole of the circuit-switcher intended to be connected to a phase
conductor
Note 1 to entry: the term "one fuse" does not preclude the use of several fuse-links in parallel.
3.4.103
fused circuit-switcher base
fused circuit-switcher without fuse-links mounted
3.5 Parts of switchgear and controlgear
Subclause 3.5 of IEC 62271-1:2017 applies, with the following additions.
3.5.101
release
device, mechanically connected to a mechanical
switching device, which releases the holding means and permits the opening or the closing of
the switching device
[SOURCE: IEC 60050-441:2000, 441-15-17]

3.5.102
shunt release
release energized by a source of voltage
Note 1 to entry: The source of voltage may be independent of the voltage of the main circuit.
[SOURCE: IEC 60050-441:2000, 441-16-41]
3.6 Operational characteristics of switchgear and controlgear
Subclause 3.6 of IEC 62271-1:2017 applies, with the following additions.
3.6.101
independent manual operation
stored energy operation where the energy originates from
manual power, stored and released in one continuous operation, such that the speed and
force of the operation are independent of the action of the operator
[SOURCE: IEC 60050-441:2000, 441-16-16]
3.6.102
stored energy operation
operation by means of energy stored in the mechanism
itself prior to the completion of the operation and sufficient to complete it under predetermined
conditions
Note 1 to entry: This kind of operation may be subdivided according to:
1) The manner of storing the energy (spring, weight, etc.);
2) The origin of the energy (manual, electric, etc.);
3) The manner of releasing the energy (manual, electric, etc.).
[SOURCE: IEC 60050-441: 2000, 441-16-15]
3.7 Characteristic quantities
Subclause 3.7 of IEC 62271-1:2017 applies, with the following additions.
3.7.101
prospective current
current that would flow in the
circuit if each pole of the switching device or the fuse were replaced by a conductor of
negligible impedance
Note 1 to entry: The method to be used to evaluate and to express the prospective current is to be specified in
the relevant publications.
[SOURCE: IEC 60050-441:2000, 441-17-01]
3.7.102
prospective peak current
peak value of a prospective current during the transient period following initiation
Note 1 to entry: The definition assumes that the current is made by an ideal switching device, i.e. with
instantaneous transition from infinite to zero impedance. For circuits where the current can follow several different
paths, e.g. polyphase circuits, it further assumes that the current is made simultaneously in all poles, even if only
the current in one pole is considered.
[SOURCE: IEC 60050-441:2000, 441-17-02]

– 12 – IEC 62271-107:2019 © IEC 2019
3.7.103
maximum prospective peak current
prospective peak current when initiation of the current takes place at the
instant which leads to the highest possible value
Note 1 to entry: For a multiple device in a polyphase circuit, the maximum prospective peak current refers to a
single pole only.
[SOURCE: IEC 60050-441:2000, 441-17-04]
3.7.104
prospective breaking current
prospective current evaluated at a time
corresponding to the instant of the initiation of the breaking process
Note 1 to entry: Specifications concerning the instant of the initiation of the breaking process are to be found in
the relevant publications. For mechanical switching devices or fuses, it is usually defined as the moment of
initiation of the arc during the breaking process.
[SOURCE: IEC 60050-441:2000, 441-17-06]
3.7.105
breaking current
current in a pole of a switching device or in a fuse at the
instant of initiation of the arc during a breaking process
[SOURCE: IEC 60050-441:2000, 441-17-07]
3.7.106
minimum breaking current
minimum value of prospective current that a fuse-link is capable of breaking at a stated
voltage under prescribed conditions of use and behaviour
[SOURCE: IEC 60050-441:2000, 441-18-29]
3.7.107
short-circuit making capacity
making capacity for which the prescribed conditions include a short circuit at the terminals of
the switching device
[SOURCE: IEC 60050-441:2000, 441-17-10]
3.7.108
take-over current
current co-ordinate of the intersection between the time-current characteristics of two over-
current protective devices
[SOURCE: IEC 60050-441:2000, 441-17-16]
3.7.109
fused short-circuit current
conditional short-circuit current when the current-limiting device is a fuse
[SOURCE: IEC 60050-441:2000, 441-17-21]

3.7.110
applied voltage
voltage which exists across the terminals of a pole of a switching
device just before the making of the current
[SOURCE: IEC 60050-441:2000, 441-17-24]
3.7.111
recovery voltage
voltage which appears across the terminals of a pole of a switching device or a fuse after the
breaking of the current
Note 1 to entry: This voltage may be considered in two successive intervals of time, one during which a transient
voltage exists, followed by a second one during which the power frequency or the steady-state recovery voltage
alone exists.
[SOURCE: IEC 60050-441:2000, 441-17-25]
3.7.112
transient recovery voltage
TRV
recovery voltage during the time in which it has a significant transient character
Note 1 to entry: The transient recovery voltage may be oscillatory or non-oscillatory or a combination of these
depending on the characteristics of the circuit and the switching device. It includes the voltage shift of the neutral
of a polyphase circuit.
Note 2 to entry: The transient recovery voltages in three-phase circuits is, unless otherwise stated, that across
the first pole to clear, because this voltage is generally higher than that which appears across each of the other
two poles.
[SOURCE: IEC 60050-441:2000, 441-17-26]
3.7.113
power frequency recovery voltage
recovery voltage after the transient voltage phenomena have subsided
[SOURCE: IEC 60050-441:2000, 441-17-27]
3.7.114
prospective transient recovery voltage
transient recovery voltage following the breaking of the prospective symmetrical
current by an ideal switching device
Note 1 to entry: The definition assumes that the switching device or the fuse, for which the prospective transient
recovery voltage is sought, is replaced by an ideal switching device, i.e. having instantaneous transition from zero
to infinite impedance at the very instant of zero current, i.e. at the "natural" zero. For circuits where the current can
follow several different paths, e.g. a polyphase circuit, the definition further assumes that the breaking of the
current by the ideal switching device takes place only in the pole considered.
[SOURCE: IEC 60050-441:2000, 441-17-29]
3.7.115
opening time
interval of time between the specified instant of initiation
of the opening operation and the instant when the arcing contacts have separated in all poles
Note 1 to entry: For release operation, instant of initiation is taken as the instant of application of power supply on
the release
[SOURCE: IEC 60050-441:2000, 441-17-36, modified – The initial note has been deleted and
the current note added.]
– 14 – IEC 62271-107:2019 © IEC 2019
3.7.116
fuse-initiated opening time
time taken from the instant at which arcing in the fuse
commences to the instant when the arcing contacts have separated in all poles
Note 1 to entry: This definition applies only for fused circuit-switchers fitted with fuse-striker release.
3.101 Fuses
3.101.1
fuse-base
fuse mount
fixed part of a fuse provided with contacts and terminals
[SOURCE: IEC 60050-441:2000, 441-18-02]
3.101.2
striker
mechanical device forming part of a fuse-link which, when the fuse operates, releases the
energy required to cause operation of other apparatus or indicators or to provide interlocking
[SOURCE: IEC 60050-441:2000, 441-18-18]
3.101.3
cut-off current
let-through current
maximum instantaneous value of current attained during the breaking operation of a switching
device or a fuse
Note 1 to entry: This concept is of particular importance when the switching device or the fuse operates in such a
manner that the prospective peak current of the circuit is not reached.
[SOURCE: IEC 60050-441:2000, 441-17-12]
3.101.4
I t
joule integral
integral of the square of the current over a given time interval:
t
2 2
I t = i dt
∫
t
2 2
Note 1 to entry: The pre-arcing I t is the I t integral extended over the pre-arcing time of the fuse.
2 2
Note 2 to entry: The operating I t is the I t integral extended over the operating time of the fuse.
Note 3 to entry: The energy in joules liberated in one ohm of resistance in a circuit protected by a fuse is equal to
2 2
the value of the operating I t expressed in A s.
[SOURCE: IEC 60050-441:2000, 441-18-23]
...