SIST EN 50151:2004

SLOVENSKI SIST EN 50151:2004
STANDARD
oct 2004
Železniške naprave – Stabilne naprave električne vleke – Posebne zahteve za
kompozitne izolatorje
Railway applications – Fixed installations – Electric traction – Special requirements
for composite insulators
ICS 29.080.10; 29.280 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 50151
NORME EUROPÉENNE
EUROPÄISCHE NORM November 2003

ICS 29.080.10; 29.280
English version
Railway applications –
Fixed installations –
Electric traction –
Special requirements for composite insulators

Applications ferroviaires –  Bahnanwendungen –
Installations fixes – Ortsfeste Anlagen –
Traction électrique – Zugförderung –
Prescriptions particulières pour Besondere Anforderungen an
les isolateurs en matière composite Verbundisolatoren

This European Standard was approved by CENELEC on 2003-10-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 50151:2003 E
Foreword
This European Standard was prepared by SC 9XC, Electric supply and earthing systems for public transport
equipment and ancillary apparatus (fixed installations), of Technical Committee CENELEC TC 9X, Electrical
and electronic applications for railways.
The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50151 on
2003-10-01.
The following dates were fixed:

- latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2004-10-01

- latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-10-01

Annexes designated "informative" are given for information only.
In this standard, Annexes A, B and C are informative.
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and supports the Public Procurement Directive
93/38/EEC.
__________
– 3 – EN 50151:2003
Contents
Page
Introduction.4
1 Scope.5
2 Normative references.5
3 Definitions .6
4 Characteristics of insulators .6
4.1 General.6
4.2 Target life.7
4.3 Purchaser requirements.7
4.4 In-running contact insulators.7
4.5 Electrical requirements .8
4.6 Mechanical requirements.9
4.7 Corrosion.10
4.8 Fire safety.10
4.9 Anti-vandalism .10
5 Design, manufacture and workmanship .10
6 Testing.11
6.1 Design tests.11
6.2 Type tests.12
6.3 Sample tests.13
6.4 Routine tests.13
7 Verification of compliance.13
7.1 Certification of compliance and test results .13
7.2 Inspection and testing .13
7.3 Test certificates.14
8 Maintenance instructions .14
9 Identification of the insulator .14
10 Delivery and packaging .14
Annex A (informative) Load time withstand curve.15
Annex B (informative) Pendulum impact test.16
Annex C (informative) Further reading list .17
Bibliography.20
Figure A.1 – A typical load-time withstand curve.15
Table 1 - System voltages.8
Table 2 - Design re-qualification tests.11
Table C.1 - Overview of publications from 1970 dealing with long-term experience
and selection criteria of composite insulators.17

Introduction
This standard specifies requirements for the design and testing of composite insulators used on railway
electrification overhead contact systems. The insulators, which are installed at relatively low heights in the
harsh environment of the railway infrastructure, require special consideration during design to reduce the
effects of vandalism and environmental pollution from railway operations, especially when combined with
a lack of natural washing. Insulators may be included in arrangements in tunnels and over bridges or be in
contact with traction unit pantographs where mechanical combined loading (tension, bending and torsion)
may require special consideration.
The standard is intended to allow the user to comply with local working practices, to ensure compatibility
with existing electrification systems, and provide an insulator which will give reliable service over its target
life span with minimum maintenance.
Insulators in overhead lines are predominately designed to resist tension and/or bending loads and are not
designed to resist torsional loads. Mitigating measures to reduce torsional loading are generally introduced
by the contact systems design engineer. Some combined loading (tension, compression and torsion) can
be experienced and this is represented in the testing procedure specified in this document.
The testing procedures given for railway applications in this standard are predominately referenced from
IEC 61109 and EN 61952.
– 5 – EN 50151:2003
1 Scope
This European Standard specifies characteristics for composite insulators for use in electric traction
overhead contact lines for railways and tramways, as defined in EN 50119. Specific applications where
high torsional loads can occur are outside the scope of this standard and particular tests should be agreed
between the supplier and purchaser, to represent the critical loading arrangements.
The provisions contained in this European Standard are for the new construction of electric traction
overhead contact lines using insulators or when complete refurbishment of existing lines takes place.
This standard provides the purchaser and manufacturer with a range of tests which are used to evaluate
the suitability of an insulator product for a given railway environment. Additional tests may be specified by
the client to measure the compliance of the insulator under particular operating conditions.
The standard establishes the product characteristics, the test methods and acceptance criteria.
The object of this European Standard is to stipulate the provisions for the design and provision of the
service indicated by the manufacturer to the purchaser or informed buyer for application on the railway
infrastructure.
2 Normative references
This European Standard incorporates, by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this European Standard only when incorporated in it by amendment or revision. For undated
references, the latest edition of the publication referred to applies (including amendments).
EN 50119 Railway applications - Fixed installatios - Electric traction overhead contact lines
EN 50124 series Railway applications - Insulation coordination
EN 50163 Railway applications - Supply voltages of traction systems
EN 60707 Flammability of solid non-metallic materials when exposed to flame sources -
List of test methods (IEC 60707)
EN 61952 Insulators for overhead lines - Composite line post insulators for alternative
current with a nominal voltage > 1 000 V (IEC 61952)
HD 405 series Test on electric cables under fire conditions (IEC 60332 series)
HD 602 Test on gases evolved during combustion of materials from cables -
Determination of degree of acidity (corrosivity) of gases by measuring pH and
conductivity (IEC 60754, mod.)
HD 606 series Measurement of smoke density of electric cables burning under defined
conditions (IEC 61034 series, mod.)
IEC 61109 Composite insulators for a.c. overhead lines with a nominal voltage greater than
1 000 V - Definitions, test methods and acceptance criteria
IEC 61467 Insulators for overhead lines with a nominal voltage above 1 000 V - AC power
arc tests on insulator sets
3 Definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
composite insulator
unit based on a core which usually consists of glass fibres positioned in a resin matrix protected with an
polymer housing and equipped with end fittings for attachment within the overhead contact line system
3.2
failing load
maximum load that is reached when testing under the prescribed conditions, when major cracking or
parting of the core occurs
3.3
specified mechanical load (SML)
short term load which can be withstood by the insulator when tested under the prescribed conditions
NOTE 1  The term SML can be prefixed by the loading type ( tension, bending or torsion).
NOTE 2  A typical load–time withstand curve diagram is given in Annex A.
3.4
maximum design load (MDL)
load above which irreversible damage to the core begins to occur
NOTE 1  The MDL should not be exceeded in service.
NOTE 2  The term MDL can be prefixed by the loading type, for example tension, bending or torsion.
3.5
nominal design load
load corresponding to the normal every day permanent and dynamic loads in the overhead line equipment
4 Characteristics of insulators
4.1 General
Composite materials and modern elastomers permit the manufacture of insulators for use on outdoor
overhead contact line systems. The insulators consist of a insulating core, bearing the mechanical load
protected by a polymeric housing, the load being transmitted to the core by end fittings. These materials
allow new and specialist applications in overhead contact line (including in-running section insulation and
flexible supports) and are also used for their advantages of lightness, resistance to vandalism and
pollution performance. Despite the common features of design, the materials used and the construction
details employed by different manufacturers may be quite different and may lead to different performance
parameters.
Overhead contact lines have several characteristics not associated with power lines. They are of low
height and run through urban areas, making them targets for vandalism. They are incorporated in bridges
and tunnels, built for rolling stock only, and fit into small spaces. They suffer close proximity to railway
generated pollution and, in tunnels and bridges are not washed by natural rainfall. They suffer movement
and snatch loads due to normal pantograph contact with the wires. When used as in-line section
insulators, they suffer mechanical forces and abrasion by the pantograph at high speed.
Some tests have been grouped together in this standard as “design tests”, to be performed only once on
insulators which satisfy the same design conditions. As far as practical, the influence of time on electrical
and mechanical properties of the components (core material, housing, interfaces etc.) and of the complete
composite insulators has been considered in specifying the design tests so that a satisfactory life-time
may be expected under normally known stress conditions of overhead contact lines.

– 7 – EN 50151:2003
The high number of insulators installed in a restricted environment of an operational railway with limited
access for maintenance requires a high level of reliability at the appropriate electrical insulation level for
the system voltage, including temporary and transient overvoltages. The insulators are required to operate
within harsh environmental conditions with a high level of mechanical integrity.
4.2 Target life
A nominal target life of 40 years in a normal railway environment is expected for insulators. However,
extreme conditions, evolution of the environment and other external factors can influence this expected
target life. This shall be borne in mind when designing the insulators and drafting maintenance instructions
for determining life cycle costs.
4.3 Purchaser requirements
The purchaser shall provide information on the railway electrification system and operating requirements
which may affect the design of insulators. This shall include, as appropriate, but not be limited to the
following:
- electrical system - service parameters (see 4.5);
- outline spatial and dimensional parameters and inclination used in service;
- ambient temperature range (maximum and minimum) of the electrification system;
- system deflection and movement constraints;
- angular movement limitations;
- nominal working loads;
- pollution and environmental considerations;
- end fittings connection requirements;
- any additional requirement for special tests;
- any special delivery, packaging or marking requirements;
- identification of inspection and tests to be witnessed by the purchaser;
- maintenance, cleaning or handling constraints;
- weight or dynamic constraints;
- vandalism frequency and impact levels;
- pantograph strip material and strip width;
- number of pantograph passes;
- pantograph speed.
4.4 In-running contact insulators
In railway applications it is essential to divide the overhead lines into discrete electrical sections. This
requires breaks or insulators in the contact wire, on which the traction pantograph runs. Polymeric
insulators can provide versatile section insulators with a small mass to minimise pantograph impacts and
damage.
Insulators in the overhead contact line which are designed to work in contact with the traction pantograph
unit require additional creepage distances depending upon the pantograph width, system voltage and
operating speed. The requirements for insulation length exceed the values in this standard and shall be
agreed separately between the supplier and purchaser .
If the insulator surface wears, it may not accumulate pollution and testing for pollution deposits may not be
required. Alternatively if the surface does not wear, pollution can build up from the pantograph strips,
which could lead to flashover or surface degradation. This shall be borne in mind when designing the
insulators and drafting maintenance instructions for determining life cycle costs.

Testing shall be in accordance with the requirements defined in 6.1.
4.5 Electrical requirements
4.5.1 System voltages
Values of standard system voltages (phase to ground) are shown in Table 1.
Table 1 - System voltages
Nominal Highest Minimum value Rated impulse Wet power
a b
permanent of rated frequency
voltages  voltage
a
U voltage  insulation withstand
n
b b
voltage  voltage
U
Nm
kV kV kV kV kV
0,6 0,72 0,72 8 4,3
0,75 0,9 0,9 12 6,5
1,5 1,8 1,8 18 10
3 3,6 3,6 25 12
c
15 17,25 170 70
c
25 27,5 200 95
c
25 36 250 95
a
In accordance with EN 50163.
b
In accordance with EN 50124.
c
See EN 50124-1, Table D.1, Note.

The purchaser shall specify the dry lightning impulse voltage, taking into account the rated impulse
voltage and short duration power frequency and wet power frequency withstand voltage.
The dry lightning impulse withstand voltage shall be at least equal to the rated impulse voltage defined in
EN 50124.
The wet power frequency withstand voltage shall be at least equal to the short duration power frequency
test level defined in EN 50124.
4.5.2 Creepage
The dry arcing distance, creepage distance and geometrical shed form electrically define an insulator.
Creepage distances shall be dimensioned according to the highest permanent voltage of the system.
Consideration shall also be given to the insulation material and its behaviour in polluted conditions. The
manufacturer may recommend greater than the minimum creepage to give adequate life for that material.
The overall shape and size of the insulator is defined by the purchaser’s spatial requirements, mechanical
and electrical performance requirements and its compatibility with existing equipment. The manufacturer
can decide on shed numbers, spacing and size.
Additional railway environmental pollution may be generated by traction braking systems, diesel and
steam trains which run under electrified lines. The exhaust from steam trains is very hot (> 200 °C) and
should not be allowed to play on insulators. This can be prevented by careful positioning of insulators in
the line or by a restriction on train movements and stopping positions. The exhaust from diesel trains is
less severe, but contains oil and carbonaceous deposits, which can contaminate insulators. Experience
shows that no additional creepage is required for diesel train operation.

– 9 – EN 50151:2003
Insulators positioned under bridges and tunnels are not washed by natural rainfall and pollution
accumulates. In these harsh environmental conditions and in order to minimise the degradation of the
housing material, the creepage length and the design need to cover the specific application. This will also
be particularly applicable to insulators which are used in contact with the pantograph collector unit
(see 4.4).
Specific creepage distance given in IEC 60815 and EN 50124-1 are only suitable for ceramic and glass
insulators in a.c. system. Specific creepage distance shall be agreed between the purchaser and
manufacturer in taking into account highest permanent voltage (U ) given in prEN 50163.
...