EN 61462:2007
(Main)Composite hollow insulators - Pressurized and unpressurized insulators for use in electrical equipment with rated voltage greater than 1 000 V - Definitions, test methods, acceptance criteria and design recommendations
Composite hollow insulators - Pressurized and unpressurized insulators for use in electrical equipment with rated voltage greater than 1 000 V - Definitions, test methods, acceptance criteria and design recommendations
This International Standard applies to composite hollow insulators consisting of a load-bearing insulating tube made of resin impregnated fibres, a housing (outside the insulating tube) made of elastomeric material (for example silicone or ethylene-propylene) and metal fixing devices at the ends of the insulating tube. The object of this standard is: To define the terms used; to prescribe test methods; and to prescribe acceptance criteria.
Verbundhohlisolatoren - Druckbeanspruchte und drucklose Isolatoren für den Einsatz in elektrischen Betriebsmitteln mit Bemessungsspannungen über 1 000 V - Begriffe, Prüfverfahren, Annahmekriterien und Konstruktionsempfehlungen
Isolateurs composites creux - Isolateurs avec ou sans pression interne pour utilisation dans des appareillages électriques de tensions nominales supérieures à 1 000 V - Définitions, méthodes d'essais, critères d'acceptation et recommandations de conception
La présente Norme internationale est applicable aux isolateurs composites creux qui sont constitués d'un tube isolant supportant la charge mécanique constitué de fibres imprégnées de résine, protégé par un revêtement en élastomère (par exemple : silicone ou éthylène-propylène) et de pièces métalliques fixées à ses extrémités. L'objet de la présente norme est de: définir les termes utilisés; prescrire des méthodes d'essai;et prescrire les critères d'acceptation.
Kompozitni votli izolatorji - Tlačni in breztlačni izolatorji za električno opremo z naznačeno napetostjo nad 1 000 V - Definicije, preskusne metode, sprejemna merila in načrtovalska priporočila (IEC 61462:2007)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2008
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QD]QDþHQRQDSHWRVWMRQDG9'HILQLFLMHSUHVNXVQHPHWRGHVSUHMHPQD
PHULODLQQDþUWRYDOVNDSULSRURþLOD ,(&
Composite hollow insulators - Pressurized and unpressurized insulators for use in
electrical equipment with rated voltage greater than 1 000 V - Definitions, test methods,
acceptance criteria and design recommendations (IEC 61462:2007)
Verbundhohlisolatoren - Druckbeanspruchte und drucklose Isolatoren für den Einsatz in
elektrischen Betriebsmitteln mit Bemessungsspannungen über 1 000 V - Begriffe,
Prüfverfahren, Annahmekriterien und Konstruktionsempfehlungen (IEC 61462:2007)
Isolateurs composites creux - Isolateurs avec ou sans pression interne pour utilisation
dans des appareillages électriques de tensions nominales supérieures a 1 000 V -
Définitions, méthodes d'essais, criteres d'acceptation et recommandations de conception
(IEC 61462:2007)
Ta slovenski standard je istoveten z: EN 61462:2007
ICS:
29.080.10 Izolatorji Insulators
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 61462
NORME EUROPÉENNE
October 2007
EUROPÄISCHE NORM
ICS 29.080.10
English version
Composite hollow insulators -
Pressurized and unpressurized insulators for use in electrical equipment
with rated voltage greater than 1 000 V -
Definitions, test methods, acceptance criteria
and design recommendations
(IEC 61462:2007)
Isolateurs composites creux - Verbundhohlisolatoren -
Isolateurs avec ou sans pression interne Druckbeanspruchte und drucklose
pour utilisation dans des appareillages Isolatoren für den Einsatz in elektrischen
électriques de tensions nominales Betriebsmitteln mit
supérieures à 1 000 V - Bemessungsspannungen über 1 000 V -
Définitions, méthodes d'essais, Begriffe, Prüfverfahren, Annahmekriterien
critères d'acceptation und Konstruktionsempfehlungen
et recommandations de conception (IEC 61462:2007)
(CEI 61462:2007)
This European Standard was approved by CENELEC on 2007-10-01. 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, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the 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
© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61462:2007 E
Foreword
The text of document 36C/167/FDIS, future edition 1 of IEC 61462, prepared by SC 36C, Insulators for
substations, of IEC TC 36, Insulators, was submitted to the IEC-CENELEC parallel vote and was
approved by CENELEC as EN 61462 on 2007-10-01.
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) 2008-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2010-10-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61462:2007 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60507 NOTE Harmonized as EN 60507:1993 (not modified).
IEC 60694 NOTE Harmonized as EN 60694:1996 (not modified).
IEC 61006 NOTE Harmonized as EN 61006:1993 (not modified).
IEC 61166 NOTE Harmonized as EN 61166:1993 (not modified).
IEC 62271-100 NOTE Harmonized as EN 62271-100:2001 (not modified).
__________
– 3 – EN 61462:2007
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60060-1 – High-voltage test techniques - HD 588.1 S1 1991
Part 1: General definitions and test
requirements
1) 2)
IEC 60068-2-17 – Environmental testing - EN 60068-2-17 1994
Part 2: Tests - Test Q: Sealing
1) 2)
IEC 60168 – Tests on indoor and outdoor post EN 60168 1994
insulators of ceramic material or glass for
systems with nominal voltages greater than
1 kV
1) 2)
IEC 62155 (mod) – Hollow pressurized and unpressurized EN 62155 2003
ceramic and glass insulators for use in
electrical equipment with rated voltages
greater than 1 000 V
1) 2)
IEC 62217 – Polymeric insulators for indoor and outdoor EN 62217 2006
use with a nominal voltage > 1 000 V - + corr. December 2006
General definitions, test methods and
acceptance criteria
1) 2)
ISO 1101 – Geometrical Product Specifications (GPS) - EN ISO 1101 2005
Geometrical tolerancing - Tolerances of form,
orientation, location and run-out
ISO 3452 Series Non-destructive testing - Penetrant EN ISO 3452 Series
inspection - General principles
1)
Undated reference.
2)
Valid edition at date of issue.
NORME CEI
INTERNATIONALE
IEC
INTERNATIONAL
Première édition
STANDARD
First edition
2007-02
Isolateurs composites creux –
Isolateurs avec ou sans pression interne pour
utilisation dans des appareillages électriques
de tensions nominales supérieures à 1 000 V –
Définitions, méthodes d’essais, critères
d’acceptation et recommandations de conception
Composite hollow insulators –
Pressurized and unpressurized insulators
for use in electrical equipment with rated
voltage greater than 1 000 V –
Definitions, test methods, acceptance criteria
and design recommendations
© IEC 2007 Droits de reproduction réservés ⎯ Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
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Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
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МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue
61462 © IEC:2007 – 3 –
CONTENTS
FOREWORD.7
INTRODUCTION.11
1 Scope and object.13
2 Normative references .15
3 Terms and definitions .15
4 Relationships of mechanical loads.23
4.1 Loads from outside the insulator.23
4.2 Pressures .23
5 Marking .23
6 Classification of tests.23
6.1 Design tests .23
6.2 Type tests .25
6.3 Sample tests .27
6.4 Routine tests .27
7 Design tests .27
7.1 General .27
7.2 Tests on interfaces and connections of end fittings.27
7.3 Tests on shed and housing material .31
7.4 Tests on the tube material .33
8 Type tests (only mechanical tests).33
8.1 General .33
8.2 Test specimens .35
8.3 Preparation of the test specimen .35
8.4 Internal pressure test.37
8.5 Bending test .37
9 Sample tests .41
9.1 Selection and number of insulators.41
9.2 Testing .41
9.3 Verification of dimensions.41
9.4 Mechanical tests.43
9.5 Galvanizing test.43
9.6 Check of the interface between end fittings and the housing.45
9.7 Re-test procedure.45
10 Routine tests .47
10.1 General .47
10.2 Visual examination .47
10.3 Routine pressure test .47
10.4 Routine mechanical test .47
10.5 Routine tightness test.49
11 Documentation .49
61462 © IEC:2007 – 5 –
Annex A (normative) Tolerances of form and position .59
Annex B (informative) General recommendations for design and construction.65
Annex C (informative) Principles of damage limit and use of reversible and irreversible
strain caused by internal pressure and/or bending loads on composite hollow insulator
tubes .75
Bibliography.81
Figure 1 – Thermal mechanical pre-stressing test – Typical cycles .51
Figure 2 – Thermal mechanical pre-stressing test – Typical test arrangement.53
Figure 3 – Test arrangement for the leakage rate test .55
Figure 4 – Examples of sealing systems for composite hollow insulators.57
Figure A.1 – Parallelism, coaxiality and concentricity .59
Figure A.2 – Angular deviation of fixing holes: Example 1 .61
Figure A.3 – Angular deviation of fixing holes: Example 2 .61
Figure A.4 – Tolerances according to standard drawing practice.63
Figure B.1 – Relationship of bending loads .73
Figure B.2 – Relationship of pressures.73
Figure C.1 – Position of strain gauges for pressure load and bending load .77
Figure C.2 – Strain/time curve, reversible elastic phase.79
Figure C.3 – Strain/time curve, irreversible plastic phase, damage limit .79
Table 1 – Mechanical loads applied to the insulator .23
Table 2 – Pressures applied to the insulator .23
Table 3 – Tests to be carried out after design changes .25
Table 4 – Sample sizes.41
Table 5 – Choice of re-test procedure .45
Table B.1 – Loads/stress and classification of tests .69
Table B.2 – Example of pressure/bending values – Practical relationship of the values.71
61462 © IEC:2007 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMPOSITE HOLLOW INSULATORS –
PRESSURIZED AND UNPRESSURIZED INSULATORS
FOR USE IN ELECTRICAL EQUIPMENT WITH RATED VOLTAGE GREATER
THAN 1 000 V –
DEFINITIONS, TEST METHODS, ACCEPTANCE CRITERIA AND
DESIGN RECOMMENDATIONS
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-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
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.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
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 61462 has been prepared by subcommittee 36C: Insulators for
substations, of IEC technical committee 36: Insulators.
This first edition cancels and replaces the first edition which was issued as a technical
specification in 1998.It constitutes a technical revision and now has the status of an
International Standard.
61462 © IEC:2007 – 9 –
The text of this standard is based on the following documents:
FDIS Report on voting
36C/167/FDIS 36C/170/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.
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.
61462 © IEC:2007 – 11 –
INTRODUCTION
Composite hollow insulators consist of an insulating tube bearing the mechanical load
protected by an elastomeric housing, the loads being transmitted to the tube by metal fittings.
Despite these common features, the materials used and the construction details employed by
different manufacturers may vary.
Some tests have been grouped together as "Design tests" to be performed only once for
insulators of the same design and material. The design tests are performed in order to eliminate
designs and materials not suitable for high-voltage applications.
The relevant design tests defined in IEC 62217 are applied for composite hollow insulators;
additional specific mechanical tests are given in this standard. The influence of time on the
electrical and mechanical properties of the complete composite hollow insulator and its
components (tube material, housing material, interfaces, etc.) has been considered in specifying
the design tests in order to ensure a satisfactory lifetime under normal service conditions. These
conditions may also depend on the equipment inside or outside the composite hollow insulators;
however, this matter has not been covered in this standard. Test methods not specified in this
standard may be considered for specific combinations of materials and specific applications,
and are a matter of agreement between manufacturers and users. In this standard, the term
“user” in general means the equipment manufacturer using composite hollow insulators.
The practical use of composite hollow insulators covers both a.c. and d.c. applications. In
spite of this fact a specific tracking and erosion test procedure for d.c. applications as a
design test has not yet been defined and accepted. The 1 000 h a.c. tracking and erosion test
of IEC 62217 is used to establish a minimum requirement for the tracking resistance of the
housing material.
This standard distinguishes between design tests and type tests because several general
characteristics of a specific design and specific combinations of materials do not vary for
different insulator types. In these cases results from design tests can be adopted for different
insulator types.
Pollution tests according to IEC 60507 are not included in this standard as they are generally
not applicable. Such pollution tests performed on insulators made of non-ceramic materials do
not correlate with experience obtained from service. Specific pollution tests for non-ceramic
insulators are under consideration.
The mechanical characteristics of composite hollow insulators are quite different compared to
those of hollow insulators made of ceramics. In order to determine the onset of mechanical
deterioration of composite hollow insulators under the influence of mechanical stress, strain
gauge measurements are used.
This standard refers to different characteristic pressures which are used for design and testing
of composite hollow insulators. The term "maximum service pressure" (MSP) is equivalent to
the term "design pressure" which is used in other standards for ceramic hollow insulators;
however, this latter term is not used in this standard in order to avoid confusion with "design"
as used in "design tests".
General recommendations for the design and construction of composite hollow insulators are
presented in Annex B.
61462 © IEC:2007 – 13 –
COMPOSITE HOLLOW INSULATORS –
PRESSURIZED AND UNPRESSURIZED INSULATORS
FOR USE IN ELECTRICAL EQUIPMENT WITH RATED VOLTAGE GREATER
THAN 1 000 V –
DEFINITIONS, TEST METHODS, ACCEPTANCE CRITERIA AND
DESIGN RECOMMENDATIONS
1 Scope and object
This International Standard applies to composite hollow insulators consisting of a load-bearing
insulating tube made of resin impregnated fibres, a housing (outside the insulating tube) made
of elastomeric material (for example silicone or ethylene-propylene) and metal fixing devices
at the ends of the insulating tube. Composite hollow insulators as defined in this standard are
intended for general use (unpressurized) or for use with a permanent gas pressure
(pressurized). They are intended for use in both outdoor and indoor electrical equipment
operating on alternating current with a rated voltage greater than 1 000 V and a frequency not
greater than 100 Hz or for use in direct current equipment with a rated voltage greater than
1 500 V.
The object of this standard is:
– to define the terms used;
– to prescribe test methods;
– to prescribe acceptance criteria.
This standard does not prescribe impulse voltage or power frequency voltage type tests, nor
does it prescribe pollution tests because the withstand voltages are not characteristics of the
hollow insulator itself, but of the apparatus of which it ultimately forms a part.
All the tests in this standard, apart from the thermal-mechanical test, are performed at normal
ambient temperature. This standard does not prescribe tests that may be characteristic of the
apparatus of which the hollow insulator ultimately forms a part. Further technical input is
required in this area.
NOTE 1 "Pressurized" means a permanent gas or liquid pressure greater than 0,05 MPa (0,5 bar) gauge. The
gas can be dry air or inert gases, for example sulphur hexafluoride, nitrogen, or a mixture of such gases.
NOTE 2 "Unpressurized" means a gas or liquid pressure smaller than or equal to 0,05 MPa (0,5 bar) gauge.
NOTE 3 Composite hollow insulators are intended for use in electrical equipment, such as, but not limited to
• circuit-breakers,
• switch-disconnectors,
• disconnectors,
• earthing switches,
• instrument- and power transformers,
• bushings.
Additional testing defined by the relevant IEC equipment committee may be required.
61462 © IEC:2007 – 15 –
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 60060-1: High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60068-2-17: Basic environmental testing procedures – Part 2: Tests – Test Q: Sealing
IEC 60168: Tests on indoor and outdoor post insulators of ceramic material or glass for
systems with nominal voltages greater than 1 000 V
IEC 62155: Hollow pressurized and unpressurized ceramic and glass insulators for use in
electrical equipment with rated voltages greater than 1 000 V
IEC 62217: Polymeric insulators for indoor and outdoor use with a nominal voltage >1 000 V-
General definitions, test methods and acceptance criteria
ISO 1101: Geometrical Product Specifications (GPS) – Geometrical tolerancing – Tolerancing
of form, orientation, location and run out
ISO 3452: Non-destructive testing – Penetrant inspection – General principles
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
composite hollow insulator
insulator consisting of at least two insulating parts, namely a tube and a housing
NOTE The housing may consist either of individual sheds mounted on the tube, with or without an intermediate
sheath, or directly applied in one or several pieces onto the tube. A composite hollow insulator unit is permanently
equipped with fixing devices or end fittings and is open from end to end.
3.2
tube
core
internal insulating part of a composite hollow insulator designed to ensure the mechanical
characteristics
NOTE 1 The tube is generally cylindrical or conical, but may have other shapes (for example barrel). The tube is
made of resin impregnated fibres.
NOTE 2 Resin impregnated fibres are structured in such a manner as to achieve sufficient mechanical strength.
Layers of different fibres may be used to fulfil special requirements.
3.3
fixing device
end fitting
part of a composite hollow insulator attached to the tube to transmit the mechanical load
61462 © IEC:2007 – 17 –
3.4
coupling
part of the end fitting which transmits the load to the accessories extrernal to the insulator
[IEC 62217, definition 3.13]
3.5
connection zone
zone where the mechanical load is transmitted between the insulating body and the end fitting
[IEC 62217, definition 3.12]
3.6
housing
external insulating part of composite hollow insulator providing necessary creepage distance
and protecting tube from environment
NOTE An intermediate sheath made of insulating material may be part of the housing.
[IEC 62217, definition 3.6, modified]
3.7
shed (of an insulator)
insulating part, projecting from the insulator trunk, intended to increase the creepage distance
NOTE The shed can be with or without ribs.
[IEV 471-01-15]
3.8
insulator trunk
central insulating part of an insulator from which the sheds project
NOTE Also known as shank on smaller insulators.
[IEV 471-01-11]
3.9
creepage distance
shortest distance or the sum of the shortest distances along the surface on an insulator
between two conductive parts which normally have the operating voltage between them
NOTE 1 The surface of cement or of any other non-insulating jointing material is not considered as forming part of
the creepage distance.
NOTE 2 If a high resistance coating is applied to parts of the insulating part of an insulator, such parts are
considered to be effective insulating surfaces and the distance over them is included in the creepage distance.
[IEV 471-01-04]
3.10
arcing distance
shortest distance in the air external to the insulator between the metallic parts which normally
have the operating voltage between them
[IEV 471-01-01]
NOTE The term “dry arcing distance” is also used.
61462 © IEC:2007 – 19 –
3.11
tracking
process which forms irreversible degradation by formation of conductive paths (tracks)
starting and developing on the surface of an insulating material
NOTE These paths are conductive even under dry conditions.
[IEC 62217, definition 3.14]
3.12
erosion
irreversible and non-conducting degradation of the surface of the insulator that occurs by loss
of material which can be uniform, localised or tree-shaped
NOTE Light surface traces, commonly tree-shaped, can occur on composite insulators as on ceramic insulators,
after partial flashover. These traces are not considered to be objectionable as long as they are non-conductive.
When they are conductive they are classified as tracking.
[IEC 62217, definition 3.15]
3.13
crack
any fracture or surface fissure of depth greater than 0,1 mm
[IEC 62217, definition 3.10]
3.14
interface
surface between the different materials
NOTE Various interfaces occur in most composite insulators, e.g.
− between housing and end fittings,
− between various parts of the housing; e.g. between sheds, or between sheath and sheds,
− between core and housing.
[IEC 62217, definition 3.10]
3.15
damage limit of the tube under mechanical stress
limit below which mechanical loads (pressure, bending load) can be applied, at normal
ambient temperature, without micro damage to the composite tube
NOTE Applying such loads means that the tube is in a reversible elastic phase. If the damage limit of the tube is
exceeded, the tube is in an irreversible plastic phase, which means permanent damage to the tube which may not
be visible at a macroscopic level (for a quantitative definition see Annex C).
3.16
specified mechanical load (SML)
load specified by the manufacturer that is used in the mechanical tests
NOTE 1 The load is normally applied by bending at normal ambient temperature.
NOTE 2 The SML forms the basis of the selection of composite hollow insulators with regard to external loads.
3.17
maximum mechanical load (MML)
highest mechanical load which is expected to be applied to the hollow insulator in service and
in the equipment in which it is used
NOTE This load is specified by the equipment manufacturer.
61462 © IEC:2007 – 21 –
3.18
deflection under bending load
displacement of a point on an insulator, measured perpendicularly to its axis, under the effect
of a load applied perpendicularly to this axis
[IEV 471-01-05]
NOTE Deflection/load relationships are determined by the manufacturer.
3.19
failing load
maximum load that can be reached when the insulator is tested under the prescribed
conditions (valid for bending or pressure tests).
NOTE Damage to the core is likely to occur at loads lower than the insulator failing load.
3.20
residual deflection
difference between the initial deflection of a hollow insulator prior to bending load application,
and the final deflection after release of the load
NOTE The measurement of residual deflection serves for comparison with strain gauge measurements.
3.21
specified internal pressure (SIP)
internal pressure specified by the manufacturer which is verified during a type test at normal
ambient temperature
NOTE The SIP forms the basis of the selection of composite hollow insulators with respect to internal pressure.
3.22
maximum service pressure (MSP)
difference between the maximum absolute internal pressure, when the equipment (of which
the hollow insulator is a part) is carrying its rated normal current at maximum operational
temperature and the normal outside pressure
NOTE 1 The MSP of the hollow insulator is specified by the equipment manufacturer.
NOTE 2 The MSP is equivalent to "design pressure" as used for ceramic hollow insulators (see IEC 62155).
3.23
specified temperature
highest and/or lowest temperature permissible for the composite hollow insulator
NOTE The specified temperature is specified by the manufacturer.
3.24
manufacturer
individual or organization producing the composite hollow insulators
3.25
equipment manufacturer
individual or organization producing the electrical equipment utilizing the composite hollow
insulators
61462 © IEC:2007 – 23 –
4 Relationships of mechanical loads
4.1 Loads from outside the insulator
Table 1 – Mechanical loads applied to the insulator
Load Relation Tube is in:
Maximum mechanical load (MML) which is the design load for reversible elastic phase
= 1,0 × MML
the equipment manufacturer
Damage limit > 1,5 × MML reversible elastic phase
Type test SML bending load = 2,5 × MML irreversible plastic phase
Failure bending load > 2,5 × MML irreversible plastic phase
An overview of loads is shown in Figure B.1.
4.2 Pressures
Table 2 – Pressures applied to the insulator
Pressure Relation Tube is in:
Maximum service pressure (MSP) which is the design = 1,0 x MSP reversible elastic phase
pressure for the equipment manufacturer
Routine test pressure = 2,0 × MSP reversible elastic phase
Damage limit > 2,0 × MSP reversible elastic phase
Type test pressure = 4,0 × MSP irreversible plastic phase
Specified internal pressure (SIP) ≥ 4,0 × MSP irreversible plastic phase
An overview of pressures is shown in Figure B.2.
5 Marking
Each hollow insulator shall be marked with the name or trade mark of the manufacturer and
the year of manufacture. In addition, each hollow insulator shall be marked with the type
reference and serial numbers in order to allow identification. This marking shall be legible and
indelible.
6 Classification of tests
The tests are divided into four groups as follows:
6.1 Design tests
These tests are intended to verify the suitability of the design, materials and manufacturing
technology.
A composite hollow insulator design is defined by:
– materials and design of the tube, housing and manufacturing method,
– material of the end fittings, their design and method of attachment,
– layer thickness of the housing over the tube (including a sheath where used).
When changes in the design occur, re-qualification shall be done according to Table 3.
61462 © IEC:2007 – 25 –
Table 3 – Tests to be carried out after design changes
IF the insulator design changes the.
THEN the following design tests shall be repeated :
7.2 7.3.1 7.3.2 7.3.3 7.3.4 7.4.1 7.4.2
Housing materials
X X X X X
a
Housing profile
X
Tube material
X X X
4 b
Tube design X X
5 c
Manufacturing process of housing X X X X
d
Manufacturing process of tube
X X X
End fitting material
X
8 e
End fitting method of attachment to tube X
Tube-housing-end fitting interface design
X X
a
The following variation of the housing profile within following tolerances do not constitute a change:
ƒ Overhang of sheds: ± 10 %
ƒ Spacing: ± 10 %
ƒ Mean inclination of sheds: ± 3°
ƒ Thickness at root and tip of sheds : ± 15 %
ƒ Shed repetition : identical
b
Liner, winding angle.
c
Curing and moulding method (e.g. extrusion, injection, single shed assembly…).
d
Pultrusion, wet filament winding, vacuum impregnation, surface preparation.
e
Applications: bending, pressure, combined pressure-bending.
6.2 Type tests
These tests are intended to verify the mechanical characteristics of a composite hollow
insulator which depends mainly on its tube and end fittings. Type tests shall be applied to the
class of composite hollow insulators which have passed the design tests. The type test shall
be repeated only when the type or the material or the manufacturing process of the composite
hollow insulator is changed.
Interfaces and
connections of
end fittings (as
per IEC 62217).
Hardness test
(see IEC 62217)
Accelerated
weathering (see
IEC 62217)
Tracking and
erosion test(see
IEC 62217)
Flammability test
(see IEC 62217)
Dye penetration
test (see
IEC 62217)
Water diffusion
test (see
IEC 62217)
61462 © IEC:2007 – 27 –
6.3 Sample tests
These tests are for the purpose of verifying the characteristics of composite hollow insulators
which depend on the manufacturing quality and the material used. They shall be made on
insulators taken at random from batches offered for acceptance.
6.4 Routine tests
These tests are for the purpose of eliminating composite hollow insulators with manufacturing
defects. They shall be made on every composite hollow insulator.
7 Design tests
7.1 General
These tests consist of three parts as described in 7.2, 7.3 and 7.4. The design tests shall be
performed only once and the results are recorded in a test report. Each part can be performed
independently on new test specimens where appropriate. The composite hollow insulator of a
particular design shall be deemed accepted only when all insulators or test specimens pass
the design tests in the given sequence within 7.2, 7.3 and 7.4.
All the design tests, apart from the thermal-mechanical test, are performed at normal ambient
temperature.
Extreme service temperatures may affect the mechanical behaviour of composite insulators.
A general rule to define “extreme high or low” insulator temperatures is not available at this
time, for this reason the supplier should always specify service temperature limitations.
Whenever the insulators are subjected to very high or low temperatures for long periods of
time, it is advisable that both manufacturer and user agree on a mechanical test at higher or
lower temperatures than that mentioned in this standard.
7.2 Tests on interfaces and connections of end fittings
See IEC 62217.
These tests shall be performed in the given sequence on the same specimen. This standard
does not use a separate reference specimen for these tests.
7.2.1 Test specimen
One hollow insulator assembled on the production line shall be tested. The tube's internal
diameter shall be at least 100 mm and the wall thickness at least 3 mm. The insulation length
(metal-to-metal spacing) shall be at least three times the tube's internal diameter but not less
than 800 mm. Both end fittings shall have the same method of attachment and sealing as on
standard production insulators. The hollow insulator shall be submitted to the routine tests
(see Clause 10).
The manufacturer shall define the MML, SML, MSP and SIP for the test specimen.
61462 © IEC:2007 – 29 –
7.2.2 Reference dry power frequency flashover test
The reference dry power frequency external flashover voltage (U ) shall be determined in
ref
accordance with IEC 60060-1 by averaging five flashover voltages. This average flashover
voltage shall be corrected to normal standard conditions as described in IEC 60060-1. The
flashover voltage shall be obtained by increasing the voltage linearly from zero to flashover
within 1 min.
Means shall be employed to avoid internal flashover, for example by filling with insulating gas.
Alternatively, the flashover voltage may be determined by splitting the arcing distance into two
sections, as equal as possible, by the use of an additional external electrode.
7.2.3 Thermal-mechanical pre-stressing test
The specimen is sequentially submitted to a mechanical load in four directions and thermal
variations.
The thermal variations consist of two cycles of heating and cooling. The duration of the cycle
shall be not shorter than 24 h and not longer than 48 h (see Figure 1).
The cold period shall be at a temperature at least 85 K below the value actually applied in the
hot period; however, the lowest temperature in the cold period shall not be lower than –50 °C.
Each of the two temperatures of the hot and cold periods respectively shall be maintained for
at least 33 % of the chosen cycle time.
The load applied to the test specimen corresponds to 0,5 × SML ± 5 %.
The load shall be applied perpendicularly to the insulator's axis either directly to the free end
of the insulator (see Figure 2) or at a distance from the free end of the insulator if special
reasons exist. When the load is not applied directly to the end fitting, the applied load shall be
corrected to give the same bending moment at the base of the insulator.
The direction of the bending test load applied to the test specimen is changed four times
corresponding to the duration of the temperature level and the corresponding time interval
described in Figures 1 and 2.
The test may be interrupted for maintenance of the test equipment for a total duration of 4 h.
The starting point after any interruption is the beginning of the interrupted cycle.
NOTE The temperatures and loads in this test are not intended to represent service conditions, they are designed
to produce specific reproducible stresses in the interfaces of the insulator.
7.2.4 Water immersion pre-stressing test
See IEC 62217.
The ends of the specimen may be sealed and vented to atmospheric pressure.
7.2.5 Verification tests
See IEC 62217.
7.2.5.1 Visual examination
See IEC 62217.
61462 © IEC:2007 – 31 –
7.2.5.2 Steep-front impulse voltage test
See IEC 62217.
7.2.5.3 Dry power frequency voltage test
See IEC 62217.
7.2.5.4 Internal pressure test
This test is not applicable for composite hollow insulators designed for unpressurized service
conditions.
The test specimen shall be subjected to an internal
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