IEC TR 62662:2010

Guidance for production, testing and diagnostics of polymer insulators with respect to brittle fracture of core materials

IEC/TR 62662:2010(E) presents an analysis of the risk of influencing factors for brittle fracture of composite insulators that are mostly loaded in the tensile mode (suspension and tension insulators). Guidance is given to reduce the risk of in-service brittle fractures.

General Information

• Status: Published
• Publication Date: 29-Aug-2010
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.080.10 - Insulators
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: TC 36 - Insulators
• Drafting Committee: MT 19 - TC 36/MT 19
• Current Stage: PPUB - Publication issued
• Start Date: 15-Dec-2010
• Completion Date: 30-Aug-2010

Standards Content (Sample)

IEC/TR 62662 ®
Edition 1.0 2010-08
TECHNICAL
REPORT
colour
inside
Guidance for production, testing and diagnostics of polymer insulators with
respect to brittle fracture of core materials

IEC/TR 62662:2010(E)
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IEC/TR 62662 ®
Edition 1.0 2010-08
TECHNICAL
REPORT
colour
inside
Guidance for production, testing and diagnostics of polymer insulators with
respect to brittle fracture of core materials

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
Q
ICS 29.080.10 ISBN 978-2-88912-172-4
– 2 – TR 62662 © IEC:2010(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Description of brittle fracture .7
5 Identification of brittle fracture .8
6 Failure mechanisms .8
6.1 Description of identified failure mechanisms.8
6.2 Mechanism M1 – Acid generated by electrical activity .8
6.3 Mechanism M2 – Acid ingress from environment .9
6.4 Mechanism M3 – Acid generated inside the core .10
7 Risk assessment .10
7.1 FMEA approach .10
7.2 Results.11
7.3 Discussions.13
8 Guidance for material selection and production .13
8.1 Rod materials and production process.13
8.1.1 Fibreglass .13
8.1.2 Resins .14
8.1.3 Rod production .14
8.2 Housing and sealing.14
9 Preventive methods.15
9.1 Sealing.15
9.2 Corona rings .15
9.3 Material selection .16
9.4 Housing quality .16
9.5 Handling, transportation and storage.16
Bibliography.17

Figure 1 – Typical brittle fracture .

Table 1 – Risk potential number (RPN) and standardized risk potential of brittle
fracture failure modes .11
Table 2 – Risk assessment of the identified brittle fracture failure modes.11

TR 62662 © IEC:2010(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDANCE FOR PRODUCTION, TESTING
AND DIAGNOSTICS OF POLYMER INSULATORS
WITH RESPECT TO BRITTLE FRACTURE OF CORE MATERIALS

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
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data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62662, which is a technical report, has been prepared by IEC technical committee 36:
Insulators.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
36/294/DTR 36/297/RVC
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.

– 4 – TR 62662 © IEC:2010(E)
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TR 62662 © IEC:2010(E) – 5 –
INTRODUCTION
There is an urgent need within utilities and industry for material standards, which define the
physical properties of the polymers applied for outdoor insulation. As a first step, a state-of-
the-art report was issued by CIGRE which led to the publication of IEC 62039. This IEC
technical report presents – as a conclusion of the CIGRE-report – the important material
properties for polymeric materials used in outdoor insulation and, where applicable, lists the
standardized test methods including the minimum requirements. The acid (brittle fracture)
resistance of FRP core materials (see 3.7) was recognized as an important property for
suspension/tension composite insulators. This technical report presents more detailed
guidance on this subject taking into account different insulator designs and production
techniques. The risk of occurrence and the influencing parameters were evaluated by failure
mode effect analysis (FMEA). Brittle fracture is not the only failure mechanism for insulators
in service and is generally less frequently observed than other modes, such as failure due to
tracking and erosion. However, this subject is not yet covered by any IEC test procedures
specifically designed to detect or prevent brittle fracture.

– 6 – TR 62662 © IEC:2010(E)
GUIDANCE FOR PRODUCTION, TESTING
AND DIAGNOSTICS OF POLYMER INSULATORS
WITH RESPECT TO BRITTLE FRACTURE OF CORE MATERIALS

1 Scope
This technical report presents an analysis of the risk of influencing factors for brittle fracture
of composite insulators that are mostly loaded in the tensile mode (suspension and tension
insulators). Guidance is given to reduce the risk of in-service brittle fractures.
This phenomenon is limited to tension and suspension insulators. However, the general
information given concerning the importance of various parameters can be used as a
guideline for the design and production of any kind of composite insulator.
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 61109, Insulators for overhead lines – Composite suspension and tension insulators for
a.c. systems with a nominal voltage greater than 1 000 V – Definitions, test methods and
...