IEC 61109:2025
(Main)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 acceptance criteria
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 acceptance criteria
IEC 61109:2025 applies to composite insulators for overhead lines consisting of a load-bearing cylindrical insulating solid core consisting of fibres - usually glass - in a resin-based matrix, a housing (surrounding the insulating core) made of polymeric material and metal end fittings permanently attached to the insulating core. Composite insulators covered by this document are intended for use as suspension/tension line insulators, but these insulators could occasionally be subjected to compression or bending, for example when used as interphase-spacers. Guidance on such loads is outlined in Annex C.
The object of this document is to:
- define the terms used,
- specify test methods,
- specify acceptance criteria.
This third edition cancels and replaces the second edition published in 2008. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- extension of this document to apply both to AC and DC systems;
- modifications of Clause 3, Terms, definitions and abbreviations;
- removal of Clause 7, Hybrid insulators, from this document;
- modifications of tests procedures recently included in IEC 62217 (hydrophobicity transfer test, stress corrosion, water diffusion test on the core with housing);
- modifications on environmental conditions;
- modifications on classification of tests and include the relevance of the interfaces;
- clarification and modification of the parameters determining the need to repeat design and type tests;
- revision of Table 1;
- revision of electrical type tests;
- revision of re-testing procedure of sample test;
- addition of a new Annex D on electric field control for AC;
- addition of a new Annex E on typical sketch for composite insulators assembly;
- addition of a new Annex F on mechanical evaluation of the adhesion between core and housing;
- addition of a new Annex G on applicability of design- and type tests for DC applications.
Isolateurs pour lignes aériennes - Isolateurs composites de suspension et d'ancrage de tension supérieure à 1 000 v en courant alternatif et à 1 500 v en courant continu - Définitions, méthodes d'essai et critères d'acceptation
L'IEC 61109:2025 s'applique aux isolateurs composites pour lignes aériennes qui sont constitués d'un noyau isolant plein cylindrique réalisé en fibres - généralement de verre - qui supporte les charges. Ces isolateurs possèdent une matrice en résine, un revêtement (recouvrant le noyau isolant) en matériau élastomère et des armatures d'extrémité métalliques fixées au noyau isolant. Les isolateurs composites couverts par le présent document sont destinés à être utilisés pour la suspension ou l'ancrage de lignes, mais ces isolateurs peuvent parfois être sollicités en compression ou en flexion, par exemple lorsqu'ils sont utilisés comme entretoises interphases. L'Annexe C fournit des recommandations pour ces types de charges.
L'objet du présent document est de:
- définir les termes utilisés;
- spécifier les méthodes d'essai;
- spécifier les critères acceptation.
Cette troisième édition annule et remplace la deuxième édition parue en 2008. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- élargissement du présent document pour inclure les systèmes à courant alternatif et à courant continu;
- modifications de l'Article 3, Termes, définitions et abréviations;
- suppression de l'Article 7, Isolateurs hybrides, dans le présent document;
- modifications des procédures d'essai récemment incluses dans l'IEC 62217 (essai de transfert d'hydrophobie, essai de corrosion sous contrainte, essai de pénétration d'eau - sur le noyau avec le revêtement);
- modifications des conditions d'environnement;
- modifications de la classification des essais et ajout de la pertinence des interfaces;
- clarification et modification des paramètres qui déterminent la nécessité de répéter les essais de conception et de type;
- révision du Tableau 1;
- révision des essais électriques de type;
- révision de la procédure de contre-épreuve de l'essai sur prélèvement;
- ajout d'une nouvelle Annexe D sur la maîtrise des champs électriques pour les applications en courant alternatif;
- ajout d'une nouvelle Annexe E sur les croquis types pour l'assemblage des isolateurs composites;
- ajout d'une nouvelle Annexe F sur l'évaluation mécanique de l'adhérence entre le noyau et le revêtement;
- ajout d'une nouvelle Annexe G sur l'applicabilité des essais de conception et de type pour les applications en courant continu.
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IEC 61109 ®
Edition 3.0 2025-02
COMMENTED VERSION
INTERNATIONAL
STANDARD
Insulators for overhead lines – Composite suspension and tension insulators
with AC voltage greater than 1 000 V and DC voltage greater than 1 500 V –
Definitions, test methods and acceptance criteria
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IEC 61109 ®
Edition 3.0 2025-02
COMMENTED VERSION
INTERNATIONAL
STANDARD
Insulators for overhead lines – Composite suspension and tension insulators
with AC voltage greater than 1 000 V and DC voltage greater than 1 500 V –
Definitions, test methods and acceptance criteria
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.080.10 ISBN 978-2-8327-0286-4
– 2 – IEC 61109:2025 CMV © IEC 2025
CONTENTS
FOREWORD .5
INTRODUCTION .7
1 Scope and object .9
2 Normative references .9
3 Terms, definitions and abbreviated terms . 10
3.1 Terms and definitions . 10
3.2 Abbreviated terms . 13
4 Identification . 13
5 Environmental conditions . 14
6 Transport, storage and installation . 15
7 Hybrid insulators .
7 Tolerances . 15
8 Classification of tests . 15
8.1 Design tests . 15
8.2 Type tests . 16
8.3 Sample tests . 17
8.4 Routine tests . 17
9 Design tests . 20
9.1 General . 20
9.2 Test specimens for IEC 62217 . 20
9.2.1 Tests on interfaces and connections of end fittings . 20
9.2.2 Tracking and erosion test . 21
9.2.3 Tests on core material . 21
9.2.4 Tests on core with housing . 21
9.3 Product specific pre-stressing for IEC 62217 tests on interfaces and
connections of end fittings . 21
9.3.1 General . 21
9.3.2 Sudden load release . 21
9.3.3 Thermal-mechanical pre-stress . 22
9.4 Assembled core load-time tests . 22
9.4.1 Test specimens . 22
9.4.2 Mechanical load test . 23
10 Type tests . 23
10.1 General . 23
10.2 Electrical tests on string insulator units. 24
10.2.1 General . 24
10.2.2 Test specimens . 24
10.2.3 Mounting arrangements for electrical tests . 24
10.2.4 Dry lightning impulse withstand voltage test . 24
10.2.5 Wet power-frequency voltage tests. 24
10.2.6 Wet switching impulse withstand voltage test . 25
10.2.7 Corona and radio interference voltage (RIV) tests . 25
10.2.8 Power arc test . 25
10.3 Damage limit proof test and test of the tightness of the interface between
end fittings and insulator housing . 26
10.3.1 Test specimens . 26
10.3.2 Performance of the test . 26
10.3.3 Evaluation of the test . 28
11 Sample tests . 28
11.1 General rules. 28
11.2 Verification of dimensions (E1 + E2) . 29
11.3 Verification of the end fittings (E2) . 29
11.4 Verification of tightness of the interface between end fittings and insulator
housing (E2) and of the specified mechanical load, SML (E1) . 29
11.5 Galvanizing test (E2) . 30
11.6 Minimum sheath thickness (E1) . 30
11.7 Re-testing procedure . 30
12 Routine tests . 32
12.1 Mechanical routine test . 32
12.2 Visual examination . 33
Annex A (informative) Principles of the damage limit, load coordination and testing for
composite suspension and tension insulators . 34
A.1 Introductory remark . 34
A.2 Load-time behaviour and the damage limit. 34
A.3 Service load coordination . 35
A.4 Verification tests . 37
Annex B (informative) Example of two possible devices for sudden release of load . 39
B.1 Device 1 (Figure B.1) . 39
B.2 Device 2 (Figure B.2) . 39
Annex C (informative) Guidance on non-standard mechanical stresses and dynamic
mechanical loading of composite tension/suspension insulators . 41
C.1 Introductory remark . 41
C.2 Torsion loads. 41
C.3 Compressive (buckling) loads . 41
C.4 Bending loads . 42
C.5 Dynamic mechanical loads . 42
C.6 Limits . 43
Annex D (informative) Electric field control for AC . 44
Annex E (informative) Typical sketches for composite insulator assemblies . 46
Annex F (informative) Mechanical evaluation of the adhesion between core and
housing . 47
F.1 General . 47
F.2 Method A: Pull-off test . 48
F.2.1 General . 48
F.2.2 Specimens . 48
F.2.3 Procedure . 48
F.3 Method B: Peel test . 50
F.3.1 General . 50
F.3.2 Specimens . 50
F.3.3 Procedure . 51
F.4 Method C: Shear test . 52
F.4.1 General . 52
F.4.2 Specimens . 52
F.4.3 Procedure . 52
Annex G (informative) Applicability of design and type tests for DC applications. 53
– 4 – IEC 61109:2025 CMV © IEC 2025
Bibliography . 55
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