IEC 62505-3-2:2009

IEC 62505-3-2 ®
Edition 1.0 2009-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Fixed installations – Particular requirements for a.c.
switchgear –
Part 3-2: Measurement, control and protection devices for specific use in a.c.
traction systems – Single-phase current transformers

Applications ferroviaires – Installations fixes – Exigences particulières pour
appareillage à courant alternatif –
Partie 3-2: Dispositifs de mesure, de commande et de protection pour usage
spécifique dans les systèmes de traction à courant alternatif – Transformateurs
de courant monophasés
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IEC 62505-3-2 ®
Edition 1.0 2009-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Fixed installations – Particular requirements for a.c.
switchgear –
Part 3-2: Measurement, control and protection devices for specific use in a.c.
traction systems – Single-phase current transformers

Applications ferroviaires – Installations fixes – Exigences particulières pour
appareillage à courant alternatif –
Partie 3-2: Dispositifs de mesure, de commande et de protection pour usage
spécifique dans les systèmes de traction à courant alternatif – Transformateurs
de courant monophasés
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
J
CODE PRIX
ICS 45.060 ISBN 978-2-88910-748-3
– 2 – 62505-3-2 © IEC:2009
CONTENTS
FOREWORD.3

INTRODUCTION.5

1 Scope.6

2 Normative references.6

3 Terms and definitions .6

4 Service conditions.7

5 Characteristics and use .7

6 Rating and design requirements.7
7 Short circuit conditions on the primary side .7
8 Particular design and construction characteristics .7
8.1 Pollution .7
8.2 Floating potentials and earthing .8
8.3 Electromagnetic compatibility.8
8.4 Connections .8
8.5 Information to be given by the purchaser.8
8.6 Information to be given by the supplier.8
9 Other requirements.9

62505-3-2 © IEC:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
RAILWAY APPLICATIONS –
FIXED INSTALLATIONS –
PARTICULAR REQUIREMENTS FOR AC SWITCHGEAR –

Part 3-2: Measurement, control and protection devices

for specific use in a.c. traction systems –

Single-phase current transformers

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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 62505-3-2 has been prepared by IEC technical committee 9:
Electrical equipment and systems for railways. This standard is based on EN 50152-3-2.
The text of this standard is based on the following documents:
FDIS Report on voting
9/1222/FDIS 9/1235/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.

– 4 – 62505-3-2 © IEC:2009
A list of all parts of IEC 62505 series, under the general title Railway applications – Fixed

installations – Particular requirements for a.c. switchgear, 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.
62505-3-2 © IEC:2009 – 5 –
INTRODUCTION
Part 3 of IEC 62505 series, “Railway applications – Fixed installations – Particular

requirements for a.c. switchgear", concerning the measurement, control and protection devices

for specific use in a.c. traction systems, comprises:

IEC 62505-3-1: Application guide (informative document)

IEC 62505-3-2: Single-phase current transformers (normative document)

IEC 62505-3-3: Single-phase inductive voltage transformers (normative document)

This International Standard applies when the equipment is concerned with the specified

characteristics.
The requirements contained in this standard complement those given in IEC 60044-1:1996,
Amendment 1 (2000), Amendment 2 (2002).

– 6 – 62505-3-2 © IEC:2009
RAILWAY APPLICATIONS –
FIXED INSTALLATIONS –
PARTICULAR REQUIREMENTS FOR AC SWITCHGEAR –

Part 3-2: Measurement, control and protection devices

for specific use in a.c. traction systems –

Single-phase current transformers

1 Scope
This part of IEC 62505 gives particular requirements for current transformers used in a.c.
single-phase railway applications, fixed installations.
This International Standard applies to current transformers used at traction voltages and
frequencies according to IEC 60850.
The main uses of these current transformers are:
− measurement;
− protection.
2 Normative references
The following referenced documents are indispensable for the application 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 60044-1:1996, Instrument transformers – Part 1: Current transformers
Amendment 1 (2000), Amendment 2 (2002)
IEC 60529:2001, Degrees of protection provided by enclosures (IP Code)
IEC 60850, Railway applications – Supply voltages of traction systems
IEC 62236 (all parts), Railway applications – Electromagnetic compatibility

IEC 62497-1, Railway applications – Insulation coordination – Part 1: Basic requirements –
Clearances and creepage distances for all electrical and electronic equipment
IEC 62505 (all parts), Railway applications – Fixed installations – Particular requirements for
a.c. switchgear
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62505-1 and in
IEC 60044-1 apply.
62505-3-2 © IEC:2009 – 7 –
4 Service conditions
Where the equipment described in this part of the standard is mounted on circuit-breakers

according to IEC 62505-1, then the service conditions of that standard apply. Where they are

separately mounted and are used in association with switchgear then the same service

conditions as the switchgear apply.

5 Characteristics and use
The current transformer shall be:

a) either mounted inside the circuit-breaker specified in IEC 62505-1 and accommodated
within special bushings on the circuit-breaker; technical requirements of this IEC 62505-3-2
apply together with the construction and test requirements (as applicable) of IEC 62505-1;
b) or separately mounted free standing; technical requirements of this IEC 62505-3-2 apply.
6 Rating and design requirements
Clauses 4 and 5 of IEC 60044-1:1996 apply with the following exceptions:
− In Subclause 4.2 the words “but the preferred value is 5 A.” shall be replaced by “but the
preferred values are 1 A or 5 A.”
− In Clause 5 the entire Subclause 5.1.1 shall be replaced by:
5.1.1 Rated insulation levels for the primary winding
Current transformers covered by this standard shall have the same insulation ratings and
test values as the equipment into which they are installed. See Table 1 of IEC 62505-1 and
IEC 62505-2. Free standing current transformers shall meet the same requirements.
− Subclause 5.1.6 of IEC 60044-1 is valid unless inconsistent with 8.1 of this Standard.
7 Short circuit conditions on the primary side
The following requirements, additional to those of IEC 60044-1:1996, apply:
Current transformers shall have a rated short time withstand current for a duration of 1 s, with
a peak value of 2,5 p.u. in accordance with the requirements of IEC 60044-1:1996.
NOTE These events occur often and special attention should be paid to protect these current transformers.
The operating sequence of the associated circuit-breaker as defined in 5.17 of IEC 62505-1

shall be taken into account
8 Particular design and construction characteristics
The following requirements, additional to those of IEC 60044-1:1996, apply:
8.1 Pollution
The dust pollution on railway tracks (e.g. in tunnels and at the seaside) is often higher than on
high voltage transmission lines. For this reason the creepage distance shall not be less than
specified in IEC 62497-1, Table A.7, for the appropriate pollution degree.
NOTE For the choice of the appropriate pollution degree, the degree used in the associated switchgear (see
IEC 62505-1 and IEC 62505-2) should be taken into account.

– 8 – 62505-3-2 © IEC:2009
8.2 Floating potentials and earthing

No metallic part of the current transformer shall be left at floating potential. The earthing

connection shall be able to carry the rated short time withstand current for a duration of 1 s.
.
8.3 Electromagnetic compatibility

The current transformer shall comply with IEC 62236 for electromagnetic compatibility.

8.4 Connections
The current transformer may be either connected on the primary side through its terminals or

be of the toroidal type, with or
...