IEC 62770:2024
(Main)Fluids for electrotechnical applications - Unused natural esters for transformers and similar electrical equipment
Fluids for electrotechnical applications - Unused natural esters for transformers and similar electrical equipment
IEC 62770:2024 describes specifications and test methods for unused natural esters in transformers and similar liquid-immersed electrical equipment in which a liquid is required as an insulating and heat transfer medium. The exposure of natural ester to air leads to deterioration of the insulating liquid. Use of natural esters is therefore restricted to sealed units, or with the conservator tank protected from the contact with atmosphere by a membrane or other suitable system.
Fluides pour applications électrotechniques - Esters naturels neufs pour transformateurs et matériels électriques analogues
IEC 62770:2024 décrit les spécifications et méthodes d'essai applicables aux esters naturels neufs dans les transformateurs et matériels électriques immergés dans du liquide analogues qui nécessitent un liquide en tant que milieu isolant et caloporteur. L'exposition de l'ester naturel à l'air entraîne une détérioration du liquide isolant. L'utilisation des esters naturels est donc limitée à des unités scellées, ou avec le conservateur protégé du contact atmosphérique par une membrane ou tout autre système approprié.
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IEC 62770 ®
Edition 2.0 2024-10
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Fluids for electrotechnical applications – Unused natural esters for transformers
and similar electrical equipment
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IEC 62770 ®
Edition 2.0 2024-10
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Fluids for electrotechnical applications – Unused natural esters for transformers
and similar electrical equipment
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.040.01 ISBN 978-2-8322-9859-6
– 2 – IEC 62770:2024 CMV © IEC 2024
CONTENTS
FOREWORD .4
INTRODUCTION .6
1 Scope .7
2 Normative references .7
3 Terms, definitions and abbreviated terms .9
3.1 Terms and definitions .9
3.2 Abbreviated terms . 10
4 Properties, their significance and test methods . 10
4.1 General . 10
4.2 Physical properties . 10
4.2.1 Appearance and colour . 10
4.2.2 Viscosity . 10
4.2.3 Pour point . 11
4.2.4 Water content . 11
4.2.5 Density . 12
4.3 Electrical properties . 12
4.3.1 Breakdown voltage . 12
4.3.2 Dielectric dissipation factor (DDF) . 12
4.3.3 Relative permittivity (dielectric constant) . 12
4.4 Chemical properties . 12
4.4.1 Acidity . 12
4.4.2 Corrosive sulfur . 12
4.4.3 Additive content. 12
4.4.4 Furfural content . 13
4.5 Performance . 13
4.5.1 General . 13
4.5.2 Oxidation stability . 13
4.6 Health, safety and environmental (HSE) properties . 14
4.6.1 Fire point and flash point . 14
4.6.2 Polychlorinated biphenyls (PCBs) . 14
4.6.3 Biodegradation . 14
4.6.4 Aquatic toxicity . 14
5 Classification, identification, general delivery requirements, and sampling . 15
5.1 Classification . 15
5.2 Identification and general delivery requirements . 15
5.3 Sampling . 15
Annexe A (normative) Summary of the test method for evaluating oxidation stability
of unused natural esters . 17
A.1 Introductory remark General . 17
A.2 Test conditions . 17
A.3 Precision . 17
A.4 Relative repeatability (r) . 17
A.5 Relative reproducibility (R) . 17
Annex B (informative) Specifications of low-viscosity insulating fluids derived from
natural esters .
Bibliography . 19
List of comments . 21
Table 1 – Abbreviated terms . 10
Table 2 – General specifications . 16
Table A.1 – Relative repeatability and relative reproducibility obtained for different
parameters during RRT . 17
Table B.1 – Specifications for low-viscosity of monoesters derived from natural esters .
– 4 – IEC 62770:2024 CMV © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FLUIDS FOR ELECTROTECHNICAL APPLICATIONS –
UNUSED NATURAL ESTERS FOR TRANSFORMERS
AND SIMILAR ELECTRICAL EQUIPMENT
FOREWORD
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This commented version (CMV) of the official standard IEC 62770:2024 edition 2.0 allows
the user to identify the changes made to the previous IEC 62770:2013
edition 1.0. Furthermore, comments from IEC TC 10 experts are provided to explain the
reasons of the most relevant changes, or to clarify any part of the content.
A vertical bar appears in the margin wherever a change has been made. Additions are in
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This publication contains the CMV and the official standard. The full list of comments is
available at the end of the CMV.
IEC 62770 has been prepared by IEC technical committee 10: Fluids for electrotechnical
applications. It is an International Standard.
This second edition cancels and replaces the first edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition: 1
a) Introduction of IEC 63012 which details other liquids not covered by this document.
IEC 63012 was published in 2019 after the first edition of IEC 62770 (2013).
b) New Table 1 inserted which clarifies definitions.
c) Appearance and colour requirements now merged.
d) Pour p
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