IEC 62271-110:2009

IEC 62271-110
Edition 2.0 2009-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage switchgear and controlgear –
Part 110: Inductive load switching

Appareillage à haute tension –
Partie 110: Manœuvre de charges inductives

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IEC 62271-110
Edition 2.0 2009-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage switchgear and controlgear –
Part 110: Inductive load switching

Appareillage à haute tension –
Partie 110: Manœuvre de charges inductives

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
T
CODE PRIX
ICS 29.130.10 ISBN 978-2-88910-656-1
– 2 – 62271-110 © IEC:2009
CONTENTS
FOREWORD.4
1 General .6
1.1 Scope.6
1.2 Normative references .6
2 Normal and special service conditions .6
3 Definitions .6
4 Ratings.7
4.1 Rated voltage (U ).7
r
4.2 Rated insulation level .7
4.3 Rated frequency (f ) .7
r
4.4 Rated normal current (I ) and temperature rise.7
r
4.5 Rated short-time withstand current (I ).7
k
4.6 Rated peak withstand current (I ).7
p
4.7 Rated duration of short-circuit (t ) .7
k
4.8 Rated supply voltage of closing and opening devices and of auxiliary and
control circuits (U ) .7
a
4.9 Rated supply frequency of closing and opening devices and auxiliary circuits .7
4.10 Rated pressure of compressed gas supply for insulation, operation and/or
interruption.7
5 Design and construction .8
6 Type tests .8
6.1 General .8
6.2 Dielectric test .8
6.3 Radio interference voltage (r.i.v.) tests .9
6.4 Measurement of the resistance of the main circuit .9
6.5 Temperature-rise tests.9
6.6 Short-time withstand current and peak withstand current tests.9
6.7 Verification of protection .9
6.8 Tightness tests .9
6.9 Electromagnetic compatibility (EMC) tests .9
6.101 Mechanical and environmental tests .9
6.102 Miscellaneous provisions for making and breaking tests .9
6.103 Test circuits for short-circuit making and breaking tests.9
6.104 Short-circuit test quantities.9
6.105 Short-circuit test procedures.9
6.106 Basic short-circuit test duties .10
6.107 Critical current tests .10
6.108 Single-phase and double-earth fault tests .10
6.114 High-voltage motor current switching tests.10
6.115 Shunt reactor current switching tests .14
7 Routine tests .19
8 Guide to selection of circuit-breakers for service .19
9 Information to be given with enquiries, tenders and orders .19
10 Rules for transport, storage, installation, operation and maintenance .20
11 Safety.20

62271-110 © IEC:2009 – 3 –
Bibliography.24

Figure 1 – Motor switching test circuit and summary of parameters.20
Figure 2 – Illustration of transient voltages at interruption of inductive current for first
phase clearing in a three-phase non-solidly earthed circuit .21
Figure 3 – Reactor switching test − Basic layout of three-phase test circuit.22
Figure 4 – Reactor switching test − Basic layout of single-phase test circuit .22
Figure 5 – Illustration of transient voltages at interruption of inductive current for a
single-phase test .23

Table 1 – Test duties at motor current switching tests.13
Table 2 – Prospective transient voltage of load circuit including connection to the
circuit-breaker.16
Table 3 – Load circuit 1 test currents .17
Table 4 – Load circuit 2 test currents .17
Table 5 – Test duties for reactor current switching tests .18

– 4 – 62271-110 © IEC:2009
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 110: Inductive load switching

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. International, governmental and non-
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 62271-110 has been prepared by subcommittee 17A: High-voltage
switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
This second edition cancels and replaces the first edition dated 2005 and constitutes an
editorial revision. The main changes from the first edition are that all references to IEC 60694
have been replaced with IEC 62271-1.

62271-110 © IEC:2009 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
17A/843/FDIS 17A/856/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 is to be read in conjunction with IEC 62271-1, first edition, published in 2007,
and with IEC 62271-100, second edition, published in 2008, to which it refers and which are
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 and
IEC 62271-100. Additional subclauses are numbered from 101.
A list of all the parts in 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 publication will remain unchanged until
the maintenance result 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.
– 6 – 62271-110 © IEC:2009
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 110: Inductive load switching

1 General
1.1 Scope
This International Standard is applicable to a.c. circuit-breakers designed for indoor or
outdoor installation, for operation at frequencies of 50 Hz and 60 Hz on systems having
voltages above 1000 V and applied for inductive current switching with or without additional
short-circuit current breaking duties. The standard is applicable to circuit-breakers in
accordance with IEC 62271-100 that are used to switch high-voltage motor currents and shunt
reactor currents and also to high-voltage contactors used to switch high-voltage motor
currents [2].
Switching unloaded transformers, i.e. breaking transformer magnetizing current, is not
considered in this standard. The reasons for this are as follows:
a) due to the non-linearity of the transformer core, it is not possible to correctly model the
switching of transformer magnetizing current using linear components in a test laboratory.
Tests conducted using an available transformer, such as a test transformer, will only be
valid for the transformer tested and cannot be representative for other transformers;
b) as detailed in CIGRE Technical Brochure 305 [1], the characteristics of this duty are
usually less severe than any other inductive current switching duty. It should be noted that
such a duty may produce severe overvoltages within the transformer winding(s) depending
on the circuit-breaker re-ignition behaviour and transformer winding resonance
frequencies.
Short-line faults, out-of-phase current making and breaking and capacitive current switching
are not applicable to circuit-breakers applied to switch shunt reactors or motors. These duties
are therefore not included in this standard.
Subclause 1.1 of IEC 62271-100 is otherwise applicable.
1.2 Normative references
Subclause 1.2 of IEC 62271-100 is applicable with the following addition:
IEC 62271-100:2008, High-voltage switchgear and controlgear – Part 100: High-voltage
alternating-current circuit-breakers
2 Normal and special service conditions
Clause 2 of IEC 62271-1 is applicable.
3 Definitions
For the purposes of this document, the definitions of IEC 60050(441) and IEC 62271-1 apply.

62271-110 © IEC:2009 – 7 –
4 Ratings
Clause 4 of IEC 62271-100 is applicable except for the references to short-line faults, out-of-
phase making and breaking, capacitive current switching and as noted in specific subclauses
below.
4.1 Rated voltage (U )
r
Subclause 4.1 of IEC 62271-1 is applicable.
4.2 Rated insulation level
Subclause 4.2 of IEC 62271-1 is applicable with the following addition:
The rated values stated in Tables 1a and 1b and Tables 2a and 2b of IEC 62271-1 are
applicable with the exception of column (8) in the latter two tables.
NOTE 1 The reason for this exception is the passive nature of the shunt reactor load circuit.
NOTE 2 In some cases (high chopping overvoltage levels, or where a neutral reactor is present or in cases of
shunt reactors with isolated neutral), it may be necessary to specify an appropriate insulation level which is higher
than the rated values given in Tables 1a, 1b, 2a and 2b.
4.3 Rated frequency (f )
r
Subclause 4.3 of IEC 62271-1 is applicable with the following addition:
The standard values for the rated frequency of high voltage circuit-breakers are 50 Hz and
60 Hz.
4.4 Rated normal current (I ) and temperature rise
r
Subclause 4.4 of IEC 62271-1 is applicable.
4.5 Rated short-time withstand current (I )
k
Subclause 4.5 of IEC 62271-100 is applicable.
4.6 Rated peak withstand current (I )
p
Subclause 4.6 of IEC 62271-100 is applicable.
4.7 Rated duration of short-circuit (t )
k
Subclause 4.7 of IEC 62271-100 is applicable.
4.8 Rated supply voltage of closing and opening devices and of auxiliary and control
circuits (U )
a
Subclause 4.8 of IEC 62271-1 is applicable.
4.9 Rated supply frequency of closing and opening devices and auxiliary circuits
Subclause 4.9 of IEC 62271-1 is applicable.
4.10 Rated pressure of compressed gas supply for insulation, operation and/or
interruption
Subclause 4.10 of IEC 62271-1 is applicable.

– 8 – 62271-110 © IEC:2009
4.101 Rated short-circuit breaking current (I )
sc
Subclause 4.101 of IEC 62271-100 is applicable.
4.102 Transient recovery voltage related to the rated short-circuit breaking current
Subclause 4.102 of IEC 62271-100 is applicable.
4.103 Rated short-circuit making current
Subclause 4.103 of IEC 62271-100 is applicable.
4.104 Rated operating sequence
Subclause 4.104 of IEC 62271-100 is applicable.
4.108 Inductive load switching
This standard is applicable.
4.109 Rated time quantities
Subclause 4.109 of IEC 62271-100 is applicable.
4.110 Number of mechanical operations
Subclause 4.110 of IEC 62271-100 is applicable.
5 Design and construction
Clause 5 of IEC 62271-100 is applicable.
6 Type tests
6.1 General
Subclause 6.1 of IEC 62271-100 is applicable with the following addition:
Inductive current switching tests performed for a given current rating and type of application
may be considered valid for another current rating and same type of application as detailed
below:
a) for high-voltage shunt reactor switching at rated voltage 52 kV and above, tests at a
particular current rating are to be considered valid for applications up to the tested current
value +20 %;
b) for shunt reactor switching at rated voltage below 52 kV, no type testing is required and
reference should be made to the guide [1];
c) for high-voltage motor switching, no further type testing is considered necessary for
stalled motor currents between 100 A and 300 A or for stalled motor currents between
300 A and the current associated with the short-circuit current of test duty T10 according
to 6.106.1 of IEC 62271-100.
6.2 Dielectric test
Subclause 6.2 of IEC 62271-100 is applicable with the following addition:

62271-110 © IEC:2009 – 9 –
Refer to 4.2 of this standard.
6.3 Radio interference voltage (r.i.v.) tests
Subclause 6.3 of IEC 62271-1 is applicable.
6.4 Measurement of the resistance of the main circuit
Subclause 6.4 of IEC 62271-1 is applicable.
6.5 Temperature-rise tests
Subclause 6.5 of IEC 62271-1 is applicable.
6.6 Short-time withstand current and peak withstand current tests
Subclause 6.6 of IEC 62271-1 is applicable.
6.7 Verification of protection
Subclause 6.7 of IEC 62271-1 is applicable.
6.8 Tightness tests
Subclause 6.8 of IEC 62271-1 is applicable.
6.9 Electromagnetic compatibility (EMC) tests
Subclause 6.9 of IEC 62271-1 is applicable.
6.101 Mechanical and environmental tests
Subclause 6.101 of IEC 62271-100 is applicable.
6.102 Miscellaneous provisions for making and breaking tests
Subclause 6.102 of IEC 62271-100 is applicable with the following addition:
High-voltage motor current and shunt reactor switching tests shall be performed at rated
auxiliary and control voltage or, where necessary, at maximum auxiliary and control voltage to
facilitate consistent control of the opening and closing operation according to 6.102.3.1 of
IEC 62271-100 and at rated functional pressure for interruption and insulation. For gas circuit-
breakers shunt reactor switching tests shall also be performed at the minimum functional
pressure for interruption and insulation.
6.103 Test circuits for short-circuit making and breaking tests
Subclause 6.103 of IEC 62271-100 is applicable.
6.104 Short-circuit test quantities
Subclause 6.104 of IEC 62271-100 is applicable.
6.105 Short-circuit test procedures
Subclause 6.105 of IEC 62271-100 is applicable.

– 10 – 62271-110 © IEC:2009
6.106 Basic short-circuit test duties
Subclause 6.106 of IEC 62271-100 is applicable.
6.107 Critical current tests
Subclause 6.107 of IEC 62271-100 is applicable.
6.108 Single-phase and double-earth fault tests
Subclause 6.108 of IEC 62271-100 is applicable.
NOTE Subclauses 6.109 to 6.112 of IEC 62271-100 are not applicable to this standard.
6.114 High-voltage motor current switching tests
6.114.1 Applicability
This subclause is applicable to three-phase alternating current circuit-breakers having rated
voltages above 1 kV and up to 17,5 kV, which are used for switching high-voltage motors.
Tests may be carried out at 50 Hz with a relative tolerance of ±10 % or 60 Hz with a relative
tolerance of ±10 %, both frequencies being considered equivalent.
Motor switching tests are applicable to all three-pole circuit-breakers having rated voltages
equal to or less than 17,5 kV, which may be used for the switching of three-phase
asynchronous squirrel-cage or slip-ring motors. The circuit-breaker may be of a higher rated
voltage than the motor when connected to the motor through a stepdown transformer.
However, the more usual application is a direct cable connection between circuit-breaker and
motor. When tests are required, they shall be made in accordance with 6.114.2 to 6.114.9.
No limits to the overvoltages are given as the overvoltages are only relevant to the specific
application. Overvoltages between phases may be as significant as phase-to-earth
overvoltages.
6.114.2 General
The switching tests can be either field tests or laboratory tests. As regards overvoltages, the
switching of the current of a starting or stalled motor is usually the more severe operation.
Due to the non-linear behaviour of the motor iron core, it is not possible to exactly model the
switching of motor current using linear components in a test station. Tests using linear
components to simulate the motors can be considered to be more conservative than switching
actual motors.
For laboratory tests a standardized circuit simulating the stalled condition of a motor is
specified (refer to Figure 1). The parameters of this test circuit have been chosen to represent
a relatively severe case with respect to overvoltages and will cover the majority of service
applications.
The laboratory tests are performed to prove the ability of a circuit-breaker to switch motors
and to establish its behaviour with respect to switching overvoltages, re-ignitions and current
chopping. These characteristics may serve as a basis for estimates of the circuit-breaker
performance in other motor circuits. Tests performed with the test currents defined in 6.114.3
and 6.114.4 demonstrate the capability of the switching device to switch high-voltage motors
up to its rated interrupting current.
For field tests, actual circuits are used with a supply system on the source side and a cable
and motor on the load side. There may be a transformer between the circuit-breaker and

62271-110 © IEC:2009 – 11 –
motor. However, the results of such field tests are only valid for circuit-breakers working in
circuits similar to those during the tests.
The apparatus under test includes the circuit-breaker with overvoltage protection devices if
they are normally fitted.
NOTE 1 Overvoltages may be produced when switching running motors. This condition is not represented by the
substitute circuit, but is regarded as less severe.
NOTE 2 The starting period switching of a slip-ring motor is generally less severe due to the effect of the starting
resistor.
NOTE 3 The rated voltage of the circuit-breaker may differ from that of the motor.
6.114.3 Characteristics of the supply circuits
6.114.3.1 General
A three-phase supply circuit shall be used. The tests shall be performed using two different
supply circuits A and B as specified in 6.114.3.2 and 6.114.3.3, respectively. Supply circuit A
represents the case of a motor connected directly to a transformer. Supply circuit B
represents the case where parallel cables are applied on the supply side.
6.114.3.2 Supply circuit A
The three-phase supply may be earthed through a high ohmic impedance so that the supply
voltage is defined with respect to earth. The impedance value shall be high enough to limit a
prospective line-to-earth fault current to a value below the test current.
The source inductance L shall not be lower than that corresponding to the rated short-circuit
s
breaking current of the tested circuit-breaker. Its impedance shall also be not higher than
0,1 times the impedance of the inductance in the load circuit (see 6.114.4).
The supply side capacitance C is represented by three capacitors connected in earthed star.
s
Their value, including the natural capacitance of the circuit shall be 0,04 µF ± 0,01 µF. The
inductance L of the capacitors and connections shall not exceed 2 µH.
b1
The busbar inductance is represented by three bars forming a busbar each 6 m ± 1 m in
length and spaced at a distance appropriate to the rated voltage.
6.114.3.3 Supply circuit B
As supply circuit A with the value of the supply side capacitance increased to
1,75 µF ± 0,25 µF.
6.114.4 Characteristics of the load circuit
6.114.4.1 General
A three-phase load circuit shall be used. The motor substitute circuit is connected to the
circuit-breaker under test by 100 m ± 10 m of screened cable. It is recommended that the
cable be connected directly to the terminals of the motor or substitute circuit.
The inductance of any intermediate connection should not exceed 3 µH. The shield of the
cable shall be earthed at both ends. The tests shall be performed using two different motor
substitute circuits as specified in 6.114.4.2 and 6.114.4.3. The inductance L of the
b2
connections between the circuit-breaker and cable shall not exceed 5 µH.

– 12 – 62271-110 © IEC:2009
6.114.4.2 Motor substitute circuit 1
Series-connected resistance and inductance shall be arranged to obtain a current of
100 A ± 10 A at a power factor less than 0,2 lagging. The star point shall not be connected to
earth. Resistance R shall be connected in parallel with each phase impedance and
p
capacitance C between each phase and earth so that the motor substitute circuit has a
p
natural frequency of 12,5 kHz ± 2,5 kHz and an amplitude factor of 1,7 ± 0,1 measured in
each phase with the other two phases connected to earth. The prospective transient recovery
voltages values shall be determined in accordance with Annex F of IEC 62271-100. A
transformer may be introduced at the load end of the cable. This shall be considered as part
of the motor substitute circuit.
6.114.4.3 Motor substitute circuit 2
As motor substitute circuit 1, but with the series resistance and inductance reduced to obtain
a current of 300 A ± 30 A at a power factor less than 0,2 lagging. The prospective transient
recovery voltage shall be as specified for motor substitute circuit 1.
6.114.5 Test voltage
a) The average value of the applied voltages shall be not less than the rated voltage U
r
divided by 3 and shall not exceed this value by more than 10 % without the consent of
the manufacturer.
The differences between the average value and the applied voltages of each pole shall not
exceed 5 %.
The rated voltage U is that of the circuit-breaker when using the substitute circuit, but is
r
that of the motor when an actual motor is used.
b) The power frequency recovery voltage of the test circuit may be stated as a percentage of
the power frequency recovery voltage specified below. It shall not be less than 95 % of the
specified value and shall be maintained in accordance with Subclause 6.104.7 of
IEC 62271-100.
The average value of the power frequency recovery voltages shall not be less than the
rated voltage U of the circuit-breaker divided by 3.
r
The power frequency recovery voltage of any pole should not deviate by more than 20 %
from the average value at the end of the time for which it is maintained.
The power frequency recovery voltage shall be measured between terminals of a pole in
each phase of the test circuit. Its r.m.s. value shall be determined on the oscillogram
within the time interval of one half cycle and one cycle of test frequency after final arc
extinction, as indicated in Figure 44 of IEC 62271-100. The vertical distance (V , V and
1 2
V respectively) between the peak of the second half-wave and the straight line drawn
between the respective peaks of the preceding and succeeding half-waves shall be
measured, and this, when divided by 2 2 and multiplied by the appropriate calibration,
gives the r.m.s. value of the recorded power frequency recovery voltage.
6.114.6 Test duties
The motor current switching tests shall consist of four test duties as specified in Table 1.

62271-110 © IEC:2009 – 13 –
Table 1 – Test duties at motor current switching tests
Test duty Supply circuit Motor substitute circuit
1 A 1
2 A 2
3 B 1
4 B 2
The number of tests for each test duty shall be:
– 20 tests with the initiation of the closing and tripping impulses distributed at intervals of
approximately 9 electrical degrees.
The above tests shall be make-breaks or separate makes and breaks except that when using
an actual motor they shall only be make-breaks. When tests are made using the motor
substitute circuit, the contacts of the circuit-breaker shall not be separated until any d.c.
component has become less than 20 %. When switching an actual motor, a make-break time
of 200 ms is recommended.
6.114.7 Test measurements
At least the following quantities shall be recorded by oscillograph or other suitable recording
techniques with bandwidth and time resolution high enough to measure the following:
– power frequency voltage;
– power frequency current;
– phase-to-earth voltage, at the motor or motor substitute circuit terminals, in all three
phases.
6.114.8 Behaviour and condition of circuit-breaker
The criteria for successful testing are as follows:
a) the behaviour of the circuit-breaker during the motor switching tests fulfils the conditions
given in 6.102.8 of IEC 62271-100 as applicable;
b) voltage tests shall be performed in accordance with 6.2.11 of IEC 62271-100;
c) re-ignitions shall take place between the arcing contacts.
6.114.9 Test report
In addition to the requirements of Annex C of IEC 62271-100, the test report shall include a
thorough description of the circuit, including the following details:
– main dimensions and characteristics of the bus and connections to the circuit-breaker;
– the characteristics of the cable:
– length;
– rated values;
– type;
– main insulation dielectric – XLPE, paper/oil, etc.;
– earthing;
– capacitances;
– surge impedance.
– the parameters of the substitute motor circuit:

– 14 – 62271-110 © IEC:2009
– natural frequency;
– amplitude factor;
– current;
– power factor.
– or details of the actual motor:
– type and rating;
– rated voltage;
– winding connection;
– rated current;
– starting current and power factor.
– overvoltage characteristics.
The following characteristics of the voltages at the motor or motor substitute circuit terminals
at each test (refer to Figure 2) shall be evaluated:
– u maximum overvoltage;
p
– u suppression peak overvoltage;
ma
– u load side voltage peak to earth;
mr
– u maximum peak-to-peak voltage excursion at re-ignition and/or prestrike.
s
When overvoltages occur which may be hazardous for a specific application, or where circuit-
breaker characteristics are required, a more comprehensive test programme will be required
which is beyond the scope of this standard.
6.115 Shunt reactor current switching tests
6.115.1 Applicability
These tests are applicable to three-phase alternating current circuit-breakers having rated
voltages of 52 kV and above, which are used for steady-state switching of shunt reactors that
are directly connected to the circuit-breaker without interposing transformer. Tests may be
carried out at 50 Hz with a relative tolerance of ±10 % or 60 Hz with a relative tolerance of
±10 %. Tests performed at either frequency shall be considered as valid for the other
frequency.
NOTE 1 By reference to CIGRÉ Technical Brochure 305 [1], shunt reactor switching tests are not required for
circuit-breakers applied to switch shunt reactors at rated voltages below 52 kV.
NOTE 2 The switching of tertiary reactors from the high-voltage side of the transformer is not covered in this
standard.
NOTE 3 Shunt reactors earthed through neutral reactors are not covered by this standard. However, the
application of test results according to this subclause, on neutral reactor earthed reactors (4-leg reactor scheme),
is discussed in CIGRÉ Technical Brochure 305 [1].
6.115.2 General
Reactor switching is an operation where small differences in circuit parameters can produce
large differences in the severity of the duty. The results from any one series of tests cannot
simply be applied to a different set of conditions.
NOTE Further guidance is given in CIGRÉ Technical Brochure 305 [1].
The switching tests can be either field tests or laboratory tests. Results from field tests are
only valid for circuit-breakers applied in circuit similar to those in the tests.

62271-110 © IEC:2009 – 15 –
Standard circuits are specified in order to demonstrate the ability of the circuit-breaker to
interrupt reactor currents and to determine chopping characteristics (suppression peak
overvoltages) and re-ignition behaviour. The parameters of these test circuits represent
typical cases of application with relatively severe transient recovery voltage (TRV) and are
regarded as covering the majority of service applications.
Laboratory tests may be made using an actual reactor but the re-ignitions and overvoltage
magnitudes during switching will not necessarily be valid for other cases of installation.
6.115.3 Test circuits
For laboratory tests, standard circuits are specified according to the following:
– a three-phase test circuit according to Figure 3;
– a single-phase test circuit according to Figure 4.
For convenience of testing, single-phase tests on one pole, or part thereof of multi-enclosure
type circuit-breakers may be performed for rated voltages of 52 kV and above representing
earthed reactors.
The requirements of 6.102.1 and 6.102.2 of IEC 62271-100 shall be fulfilled.
In non-solidly earthed systems and for three-pole in one enclosure type circuit-breakers a
three-phase test circuit shall be used. The reactor neutral point may be earthed as applicable
in the latter case.
For non-earthed reactors on solidly earthed systems, three-pole testing is impractical at
higher rated voltages. Single-pole testing is permissible on the basis that the neutral point is
earthed prior to in-service switching or that the methodology described in CIGRÉ Technical
Brochure 305 [1] is used to determine the suitability of the circuit-breaker for the application.
The switchgear under test shall include the circuit-breaker with overvoltage protection devices
if they are normally fitted.
When overvoltage limiting devices are added in the test circuit for its protection against
possible excessive overvoltages, it shall be proven that these devices have not limited the
overvoltages recorded during the tests, for instance by recording the current through these
devices.
6.115.4 Characteristics of the supply circuit
The source inductance L shall not be smaller than that corresponding to the rated short-
s
circuit current of the circuit-breaker, nor larger than 10 % of the inductance of the load
circuit L.
The source capacitance C shall be at least 10 times the load capacitance C .
s L
The TRV of the supply circuit has a negligible influence on that of the complete circuit and is
therefore not specified.
6.115.5 Characteristics of the connecting leads
The total inductance L = L + L of the leads may be shared between the supply and the
b b1 b2
load side. The value of L is not specified but should be as small as possible.
b
6.115.6 Characteristics of the load circuits
6.115.6.1 General
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The load circuits shall consist of a reactor, or alternatively, an air-cored or iron-cored
reactance with appropriate shunt capacitance and resistance so as to produce a prospective
transient voltage not less severe than the values specified in Table 2.
Table 2 – Prospective transient voltage of load circuit
including connection to the circuit-breaker
+0
Time parameter t %
Rated voltage Peak voltage
−20
U u
r c
Load circuit 1 Load circuit 2
kV kV
µs µs
52 121 54 95
72,5 169 63 112
100 233 105 186
123 286 116 207
145 337 126 224
170 396 137 243
245 380 164 290
300 465 181 321
362 562 199 353
420 652 214 380
550 853 245 435
800 1 241 296 525
u and t as defined in 4.102 of IEC 62271-100.
c 3
NOTE 1 The transient voltage is of a damped (1-cos) form and the values are for the first pole-to-clear.
NOTE 2 The first-pole-to-clear factor k is 1,0 for rated voltages of 245 kV and above assuming reactors with
pp
earthed neutral and 1,5 for rated voltages below 245 kV assuming reactors with isolated neutral. The amplitude
factor k is assumed to be 1,9.
af
u = U × k × 1,9
c r pp
NOTE 3 The values of t are based on a mean capacitance value of load side capacitance C of
L
− 1 750 pF for voltages at or above 52 kV and below 245 kV;
− 2 600 pF for voltages of 245 kV and above.
NOTE 4 The recovery voltages given in the table are not necessarily representative for field application, but are
suitable to determine the current chopping behaviour of the circuit-breaker. In the case that a re-ignition-free
window has to be demonstrated, the TRV time parameter may need to be adjusted to actual service conditions.

The values of t are based on a calculation at 50 Hz. There is no need to differentiate
between 50 Hz and 60 Hz since the stress of the tests with both frequencies is equivalent.
This is taken into account by the overlapping tolerances for the frequency of the test current.
6.115.6.2 Load circuit 1
The inductance L of the load circuit shall be adjusted to give the following breaking currents:

62271-110 © IEC:2009 – 17 –
Table 3 – Load circuit 1 test currents
Rated voltage Test current
A
kV
± 20 %
52 – 72,5 630
≥100 315
6.115.6.3 Load circuit 2
The inductance L of the load shall be adjusted to give the following breaking currents:
Table 4 – Load circuit 2 test currents
Rated voltage Test current
A
kV
± 20 %
52 – 72,5 200
≥100
However, if the circuit-breaker is used to switch reactor currents smaller than these values,
the load circuit 2 should be adjusted to give the lower limit of the actual current range. Tests
performed at a minimum current are valid for all higher current applications up to the rated
current of the circuit-breaker.
6.115.7 Earthing of t
...