IEC 62497-2:2010

Railway applications - Insulation coordination - Part 2: Overvoltages and related protection

IEC 62497-2:2010 gives simulation and/or test requirements for protection against transient overvoltages and applies to fixed installations (downstream the secondary of the substation transformer) and rolling stock equipment linked to the contact line of one of the systems defined in IEC 60850; rolling stock equipment linked to a train line.

Applications ferroviaires - Coordination de l'isolement - Partie 2: Surtensions et protections associées

La CEI 62497-2:2010 donne des exigences relatives à la simulation et/ou aux essais concernant les protections contre les surtensions et s'applique aux installations fixes (en aval du secondaire du transformateur de la sous-station) et à l'équipement du matériel roulant connecté à la ligne de contact de l'un des systèmes définis dans la CEI 60850; à l'équipement du matériel roulant connecté à la ligne de train.

General Information

• Status: Published
• Publication Date: 17-Feb-2010
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: TC 9 - Electrical equipment and systems for railways
• Drafting Committee: PT 62497 - TC 9/PT 62497
• Current Stage: PPUB - Publication issued
• Start Date: 18-Feb-2010
• Completion Date: 15-Feb-2010

Overview

IEC 62497-2:2010 is an international standard published by the International Electrotechnical Commission (IEC) focused on insulation coordination specifically addressing overvoltages and related protection for railway applications. This standard defines simulation and test requirements aimed at protecting fixed installations and rolling stock equipment connected to railway traction systems. It provides critical guidelines for handling transient overvoltages downstream of substation transformers and on train lines, ensuring the electrical safety and reliability of railway systems.

Key Topics

• Scope and Application: The standard applies to fixed installations downstream of substation transformers and rolling stock linked to contact lines defined by IEC 60850, as well as train line equipment. It excludes long-term overvoltages, focusing instead on transient overvoltages occurring during switching or lightning events.
• Overvoltage Definitions: It classifies overvoltages into temporary (longer duration, voltage variation-related) and transient (short duration from current transfer). Specific transient types include switching overvoltages and lightning overvoltages.
• Protection Requirements: Guidance on protection using metal-oxide surge arresters including simulation of their behavior under long (2 ms trapezoidal pulse) and short (4/10 µs current pulse) voltage pulses. If not protected by arresters, equipment must consider intrinsic isolation limits and additional spark gaps or arresters.
• Simulation and Testing: Detailed simulation methodologies are provided to ensure equipment can withstand defined voltage pulses, including replacing physical arresters with theoretical models for testing. Where simulations are inconclusive, tests are mandated.
• Equipment Categories: The standard outlines different scenarios for equipment protected or unprotected by metal-oxide arresters both on the contact line network and the train line network.
• Voltage Reference Values: Reference voltages are established based on nominal network voltages per IEC 60850, which form the basis for simulation amplitudes and test criteria.

Applications

IEC 62497-2:2010 is critical for:

• Railway Infrastructure Manufacturers: Designing and testing fixed installations, such as substations and trackside electrical equipment, to withstand transient overvoltages.
• Rolling Stock Manufacturers: Ensuring that trains’ electrical systems can endure and safely operate under transient overvoltage conditions.
• System Integrators and Operators: Implementing and verifying protective devices like metal-oxide surge arresters and coordinating insulation to minimize electrical failures and safety incidents during transient voltage events.
• Electrical Safety Compliance: Meeting international standards for railway electrical equipment insulation to reduce risks of insulation breakdown and ensure operational reliability.

Related Standards

• IEC 60850: Defines supply voltages for railway traction systems, essential for reference voltages and system parameters in IEC 62497-2.
• IEC 60099 Series: Includes surge arrester standards -
  • IEC 60099-1 covers non-linear resistor type gapped arresters for AC systems.
  • IEC 60099-4 addresses metal-oxide surge arresters without gaps for AC systems.
• IEC 61992-5: Specific to DC systems, this standard deals with surge arresters and low-voltage limiters used in railway fixed installations.
• UIC 550: Guidelines for power supply installations in passenger rolling stock, applicable when equipment is not protected by metal-oxide arresters.
• IEC 62497-1: Companion part covering basic insulation coordination requirements, including clearances and creepage distances for railway electrical equipment.

---

Adopting IEC 62497-2:2010 enhances transient overvoltage protection strategies in railway systems, supporting safe, reliable, and internationally compliant electrical installations and rolling stock design. This facilitates the integration of surge arresters, simulation-based validation, and rigorous testing protocols to mitigate the impact of switching and lightning overvoltages on railway infrastructure.

Standards Content (Sample)

IEC 62497-2 ®
Edition 1.0 2010-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Insulation coordination –
Part 2: Overvoltages and related protection

Applications ferroviaires – Coordination de l'isolement –
Partie 2: Surtensions et protections associées

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IEC 62497-2 ®
Edition 1.0 2010-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Insulation coordination –
Part 2: Overvoltages and related protection

Applications ferroviaires – Coordination de l'isolement –
Partie 2: Surtensions et protections associées

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
M
CODE PRIX
ICS 45.060 ISBN 978-2-88910-742-1
– 2 – 62497-2 © IEC:2010
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Contact line network.7
4.1 Equipment not protected by a metal-oxide arrester.7
4.2 Equipment protected by a metal-oxide arrester.7
4.2.1 General .7
4.2.2 Simulation for long pulse .8
4.2.3 Simulation for short pulse .8
5 Train line network.8
5.1 Equipment not protected by a metal-oxide arrester.8
5.2 Equipment protected by a metal-oxide arrester.8
6 Tests .9
Annex A (informative) Maximum value of voltage U according to duration.10
Bibliography.12

Figure A.1 – Maximum value of voltage U according to duration .10

Table 1 – Values of the reference voltage U .8
p
Table A.1 – Overvoltages.11

62497-2 © IEC:2010 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RAILWAY APPLICATIONS –
INSULATION COORDINATION –
Part 2: Overvoltages and related protection

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 62497-2 has been prepared by IEC technical committee 9:
Electrical equipment and systems for railways.
This standard is based on EN 50124-2.
The text of this standard is based on the following documents:
FDIS Report on voting
9/1336/FDIS 9/1359/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 – 62497-2 © IEC:2010
A list of all parts of IEC 62497 series, under the general title Railway applications – Insulation
coordination, can be found 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.
62497-2 © IEC:2010 – 5 –
INTRODUCTION
This International Standard is part of the series IEC 62497, Railway applications – Insulation
coordination.
IEC 62497 consists of two parts:
– IEC 62497-1: Part 1: Basic requirements – Clearances and creepage distances for all
electrical and electronic equipment;
– IEC 62497-2: Part 2: Overvoltages and related protection.
This part 2 deals with the shortest durations of overvoltages referred to as Zone A and Zone B
in Figure A.1 in informative Annex A.

– 6 – 62497-2 © IEC:2010
RAILWAY APPLICATIONS –
INSULATION COORDINATION –
Part 2: Overvoltages and related protection

1 Scope
This part of IEC 62497 applies to:
– fixed installations (downstream the secondary of the substation transformer) and rolling
stock equipment linked to the contact line of one of the systems defined in IEC 60850;
– rolling stock equipment linked to a train line.
This standard gives simulation and/or test requirements for protection against transient
overvoltages of such equipment.
Long-term overvoltages are not treated in this standard.
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 60099-1, Surge arresters – Part 1: Non-linear resistor type gapped arresters for a.c.
systems
IEC 60099-4, Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c.
systems
IEC 60850, Railway applications – Supply voltages of traction systems
IEC 61992-5, Railway applications – Fixed installations – D.C. switchgear – Part 5: Surge
arresters and low-voltage limiters for specific use in d.c. systems
UIC 550, Power supply installations for passenger stock
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1
voltages
3.1.1
overvoltage
any voltage having a peak value exceeding the corresponding peak value of maximum
steady-state voltage at normal operating conditions
3.1.2
temporary overvoltage
an overvoltage of relatively long duration due to voltage variations

62497-2 © IEC:2010 – 7 –
NOTE A temporary overvoltage is independent of the network load. It is characterized by a voltage/time curve.
3.1.3
transient overvoltage
A short duration overvoltage of a few milliseconds or less due to current transfer
NOTE A transient overvoltage depends on the network load. It cannot be characterised by a voltage/time curve.
Basically, a transient overvoltage is the result of a current transfer from a source to the load (network).
3.1.3.1
switching overvoltage
the transient overvoltage at any point of the system due to specific switching operation or fault
[IEC 60664-1, 3.7.3]
3.1.3.2
lightning overvoltage
the transient overvoltage at any point of the system due to a specific lightning discharge
3.2
network
set of conductors fulfilling a certain function, the overvoltages of which are likely to damage
the equipment they are connected to
4 Contact line network
NOTE The provisions of this Clause 4 do not take into account rapid transient overvoltages in the multimegahertz
range such as generated by operation of vacuum circuit breakers which may require a specific overvoltage
protection.
4.1 Equipment not protected by a metal-oxide arrester
If the equipment is not protected by a metal-oxide arrester, the protection against
overvoltages shall take into account overvoltages limited only by the intrinsic isolation of the
contact line and the possible presence of other types of arrester or spark gaps.
4.2 Equipment protected by a metal-oxide arrester
4.2.1 General
If the supplier wants to benefit from the presence of a metal-oxide arrester for reducing
constraints resulting from 4.1, he shall perform a simulation of the behaviour of the protection
against overvoltages.
The circuits of the protected equipment likely to modify the electrical behaviour of the
protection shall also be simulated.
The equipment shall withstand the pulses defined in 4 . 2.2 an d 4.2.3, where the values of the
reference voltage U are defined in Table 1.
p
– 8 – 62497-2 © IEC:2010
Table 1 – Values of the reference voltage U

p
Nominal network voltage
according to IEC 60850
U
n
U
p
kV
kV
0,75 4
1,5 6
3 12
15 60
20 80
25 100
a
25 110
NOTE The values of U take into account the values of U as given in IEC 60099-
p res
1 and IEC 60099-4 and/or U as given in IEC 61992-5. But they relate to a
p
theoretical arrester, for simulation purposes only, and present not any direct link to
U of IEC 60099-1 and IEC 60099-4 and/or U of IEC 61992-5.
res p
a
See footnote i to Table 1 of IEC 60850 regarding nominal voltage 25 kV.

4.2.2 Simulation for long pulse
The long pulse is a voltage pulse of trapezoidal shape, lasting 2 ms with an amplitude equal
to 70 % of the reference voltage U . It is applied to the equipment without considering the
p
presence of its metal-oxide arrester.
4.2.3 Simulation for short pulse
The short pulse is the 4/10 current pulse defined in IEC 60099-4.
Its amplitude value is 100 kA.
It is applied to the equipment including the arrester, where the metal-oxide arrester is
replaced by a theoretical one the characteristic of which, in log(current in kA) versus
log(voltage in kV), is a straight line which includes the two points:
(log(10), log(U )) and (log(100), log(1,5 U )).
p p
NOTE The safety margin 1,5 U takes into account residual voltages of the surge arrester at lightning impulse
p
currents higher than 10 kA, induced voltage drops along the arrester and the connection lines and voltage
increases due to travelling wave effects on the line between the surge arrester and the equipment.
5 Train line network
5.1 Equipment not protected by a metal-oxide arrester
If the equipment is not protected by a metal-oxide arrester, UIC 550 shall be applied.
5.2 Equipment protected by a metal-oxide arrester
If the equipment is protected by a metal-oxide arrester, the values of UIC 550 may be limited
according to the characteristics of the metal-oxide arrester.

62497-2 © IEC:2010 – 9 –
In case of connection of several arresters to the train line, it shall be ascertained that their
cascading will not lead to damages.
6 Tests
In case of doubt on the model and/or the parameters to be taken into account in the
simulation, investigation tests shall be carried out and the simulation improved until an
acceptable level of trust is reached.
The supplier shall ascertain that each component involved is chosen and tested in order to
withstand the worst constraints resulting from the simulation.
If the simulation shows constraints on a component which are not covered by its product
standard or data sheet, or if both documents are missing, a dedicated test shall be carried out
upon agreement between purchaser and supplier.
One or several tests on components may be replaced, if deemed preferable by the supplier,
by a unique test on the assembled equipment.

– 10 – 62497-2 © IEC:2010
Annex A
(informative)
Maximum value of voltage U according to duration

NOTE 1 This annex A is cited in the introduction and Clause 3.
NOTE 2 This annex A is cited in Annex A of IEC 60850.

Voltage U
U
max3
U
max2
U
max1
Duration t
1 µs 1 ms 1 000 s
1 s
(log scale)
20 µs 20 ms 5 min
Zone A Zone B Zone C Zone D Zone E
Energy Voltage
IEC  042/10
Key
Zone A: Lightning overvoltages
Zone B: Switching overvoltages, due to high impedance phenomena (currents
...