FprEN IEC 62770:2024

SLOVENSKI STANDARD
oSIST prEN IEC 62770:2023
01-junij-2023
Tekočine za elektrotehniko - Neuporabljene naravne estrske tekočine za
transformatorje in podobno električno opremo
Fluids for electrotechnical applications - Unused natural esters for transformers and
similar electrical equipment
Flüssigkeiten für elektrotechnische Anwendungen - Neue natürliche Ester für
Transformatoren und ähnliche elektrische Betriebsmittel
Fluides pour applications électrotechniques - Esters naturels neufs pour transformateurs
et matériels électriques analogues
Ta slovenski standard je istoveten z: prEN IEC 62770:2023
ICS:
29.040.01 Izolacijski fluidi na splošno Insulating fluids in general
29.180 Transformatorji. Dušilke Transformers. Reactors
oSIST prEN IEC 62770:2023 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN IEC 62770:2023
oSIST prEN IEC 62770:2023
10/1195/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62770 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2023-04-07 2023-06-30
SUPERSEDES DOCUMENTS:
10/1178/CD, 10/1193/CC
IEC TC 10: FLUIDS FOR ELECTROTECHNICAL APPLICATIONS
SECRETARIAT: SECRETARY:
Italy Mr Massimo Pompili
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:

TC 14, SC 17A, TC 20, SC 36A, TC 38, TC 99, TC 112
Other TC/SCs are requested to indicate their interest, if any, in
this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for Vote
(CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of
• any relevant patent rights of which they are aware and to provide supporting documentation,
• any relevant “in some countries” clauses to be included should this proposal proceed. Recipients are reminded that the
enquiry stage is the final stage for submitting "in some countries" clauses. See AC/22/2007.

TITLE:
Fluids for electrotechnical applications – Unused natural esters for transformers and similar electrical
equipment
PROPOSED STABILITY DATE: 2027
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

oSIST prEN IEC 62770:2023
– 2 – CDV IEC 62770  IEC 2023
CONTENTS
CONTENTS . 2
FOREWORD . 3
INTRODUCTION . 5
Scope . 6
Normative references . 6
3 Terms and definitions . 8
Properties, their significance and test methods . 8
4.1 General . 8
4.2 Physical properties . 8
4.2.1 Appearance & Colour . 8
4.2.2 Viscosity . 8
4.2.3 Pour point . 8
4.2.4 Water content. 9
4.2.5 Density . 9
4.3 Electrical properties . 9
4.3.1 Breakdown voltage . 9
4.3.2 Dielectric dissipation factor (DDF) . 9
4.3.3 Relative permittivity (dielectric constant) . 9
4.4 Chemical properties . 10
4.4.1 Acidity . 10
4.4.2 Corrosive sulfur . 10
4.4.3 Additive content . 10
4.4.4 Furfural content . 10
4.5 Performance . 10
4.6.1 Fire point and flash point . 11
4.6.4 Toxicity . 11
5.0 Classification, identification, general delivery requirements and sampling . 11
5.2 Identification and general delivery requirements . 12
5.3 Sampling . 12
Annex A (normative) Summary of the test method for evaluating oxidation stability of
unused natural esters . 14
A.1 Introductory remark . 14
A.2 Test conditions . 14
A.3 Precision . 14
A.4 Relative repeatability (r) . 14
A.5 Relative reproducibility (R) . 14
Bibliography . 15

Table 1 – General specifications . 12
Table A.1 – Relative repeatability and relative reproducibility obtained for different
parameters during RRT . 14

oSIST prEN IEC 62770:2023
CDV IEC 62770  IEC 2023 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FLUIDS FOR ELECTROTECHNICAL APPLICATIONS –
UNUSED NATURAL ESTERS FOR TRANSFORMERS
AND SIMILAR ELECTRICAL EQUIPMENT

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
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6) All users should ensure that they have the latest edition of this publication.
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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 62770 has been prepared by IEC technical committee 10: Fluids
for electrotechnical applications.
The text of this standard is based on the following documents:
FDIS Report on voting
10/XXXX/FDIS 10/XXXX/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.

oSIST prEN IEC 62770:2023
– 4 – CDV IEC 62770  IEC 2023
The committee has decided that the contents of this publication will remain unchanged until
the stability 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.
oSIST prEN IEC 62770:2023
CDV IEC 62770  IEC 2023 – 5 –
1 INTRODUCTION
2 Because of their higher fire points and lower environmental impact relative to hydrocarbon
3 petroleum derived insulating mineral oil, the use of vegetable oils and other natural esters is
4 on the rise as insulating and heat transfer fluids in electrical devices such as transformers.
5 This standard sets performance criteria for unused natural esters earmarked for electrical
6 applications. However, the use of natural esters is recommended only for equipment that is
7 not open to the atmosphere, e.g. sealed transformers and reactors because these liquids are
8 susceptible to rapid oxidation.
9 This International Standard does not purport to address all the safety problems associated
10 with its use. It is the responsibility of the user of the standard to establish appropriate health
11 and safety practices and determine the applicability of regulatory limitation prior to use.
12 Unused natural esters which are the subject of this standard should be handled with due
13 regard to personal hygiene. Direct contact with eyes should be avoided. In case of eye
14 contact, irrigation with copious amounts of clean running water should be carried out and
15 medical advice sought.
16 Performance of some of the tests mentioned in this standard could lead to a hazardous
17 situation. Attention is drawn to the relevant standard test method for guidance.
18 The disposal of natural esters, chemicals and sample containers mentioned in this standard
19 should be carried out in accordance with current national legislation with regard to the impact
20 on the environment. Every precaution should be taken to prevent the release of natural esters
21 into the environment.
oSIST prEN IEC 62770:2023
– 6 – CDV IEC 62770  IEC 2023
23 FLUIDS FOR ELECTROTECHNICAL APPLICATIONS –
24 UNUSED NATURAL ESTERS FOR TRANSFORMERS
25 AND SIMILAR ELECTRICAL EQUIPMENT
28 Scope
29 This International Standard describes specifications and test methods for unused natural
30 esters in transformers and similar liquid-impregnated electrical equipment in which a liquid is
31 required as an insulating and heat transfer medium.
32 Use of natural esters is not recommended for electrical equipment that is open to the
33 atmosphere. The exposure of natural ester to air leads to rapid deteriorati
...