SIST EN 62770:2014

SLOVENSKI STANDARD
SIST EN 62770:2014
01-julij-2014
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WUDQVIRUPDWRUMHLQSRGREQRHOHNWULþQRRSUHPR,(&
Fluids for electrotechnical applications - Unused natural esters liquids for transformers
and similar electrical equipment
/
Fluides pour applications électrotechniques - Esters naturels neufs pour transformateurs
et matériels électriques analogues
Ta slovenski standard je istoveten z: EN 62770:2014
ICS:
29.040.01 Izolacijski fluidi na splošno Insulating fluids in general
29.180 Transformatorji. Dušilke Transformers. Reactors
SIST EN 62770:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 62770:2014

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SIST EN 62770:2014

EUROPEAN STANDARD
EN 62770

NORME EUROPÉENNE
April 2014
EUROPÄISCHE NORM

ICS 29.040


English version


Fluids for electrotechnical applications -
Unused natural esters for transformers and similar electrical equipment
(IEC 62770:2013)


Fluides pour applications Flüssigkeiten für elektrotechnische
électrotechniques - Anwendungen -
Esters naturels neufs pour Neue natürliche Ester für Transformatoren
transformateurs et matériels électriques und ähnliche elektrische Betriebsmittel
analogues (IEC 62770:2013)
(CEI 62770:2013)



This European Standard was approved by CENELEC on 2013-12-24. 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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2014 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62770:2014 E

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SIST EN 62770:2014
EN 62770:2014 - 2 -
Foreword
The text of document 10/909/FDIS, future edition 1 of IEC 62770, prepared by IEC TC 10 "Fluids for
electrotechnical applications" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 62770:2014.
The following dates are fixed:

• latest date by which the document has (dop) 2014-10-18
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2016-12-24
• latest date by which the national
standards conflicting with the

document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.

Endorsement notice
The text of the International Standard IEC 62770:2013 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 60422 NOTE Harmonised as EN 60422.
IEC 61039 NOTE Harmonised as EN 61039.
IEC 61099 NOTE Harmonised as EN 61099.
IEC 61868 NOTE Harmonised as EN 61868.

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SIST EN 62770:2014
- 3 - EN 62770:2014
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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


IEC 60076-14 - Power transformers - EN 60076-14 -
Part 14: Liquid-immersed power transformers
using high-temperature insulation materials


IEC 60156 - Insulating liquids - Determination of the EN 60156 -
breakdown voltage at power frequency - Test
method


IEC 60247 - Insulating liquids - Measurement of relative EN 60247 -
permittivity, dielectric dissipation factor (tan d)
and d.c. resistivity


IEC 60296 - Fluids for electrotechnical applications - EN 60296 -
Unused mineral insulating oils for
transformers and switchgear


IEC 60475 - Method of sampling insulating liquids EN 60475 -


IEC 60666 - Detection and determination of specified EN 60666 -
additives in mineral insulating oils


IEC 60814 - Insulating liquids - Oil-impregnated paper and EN 60814 -
pressboard - Determination of water by
automatic coulometric Karl Fischer titration


1)
IEC 61100 - Classification of insulating liquids according to EN 61100 -
fire point and net calorific value


IEC 61125 1992 Unused hydrocarbon based insulating liquids - EN 61125 1993
Test methods for evaluating the oxidation
stability


IEC 61198 - Mineral insulating oils - Methods for the EN 61198 -
determination of 2-furfural and related
compounds


IEC 61619 - Insulating liquids - Contamination by EN 61619 -
polychlorinated biphenyls (PCBs) - Method of
determination by capillary column gas
chromatography


IEC 61620 - Insulating liquids - Determination of the EN 61620 -
dielectric dissipation factor by measurement of
the conductance and capacitance - Test
method



1)
Withdrawn in 2009 and partially replaced by IEC 61039.

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SIST EN 62770:2014
EN 62770:2014 - 4 -
IEC 62021-3 - Insulating liquids - Determination of acidity - EN 62021-3 -
Part 3: Test methods for non mineral
insulating oils


IEC 62535 2008 Insulating liquids - Test method for detection EN 62535 2009
of potentially corrosive sulphur in used and
unused insulating oil


IEC 62697-1 - Test method for quantitative determination of EN 62697-1 -
corrosive sulfur compounds in unused and
used insulating liquids -
Part 1: Test method for quantitative
determination of dibenzyldisulfide (DBDS)


ISO 2592 - Determination of flash and fire points - - -
Cleveland open cup method


ISO 2719 - Determination of flash point - Pensky-Martens - -
closed cup method


ISO 3016 - Petroleum products - Determination of pour - -
point


ISO 3104 - Petroleum products - Transparent and opaque - -
liquids - Determination of kinematic viscosity
and calculation of dynamic viscosity


ISO 3675 - Crude petroleum and liquid petroleum - -
products - Laboratory determination of density
- Hydrometermethod


ISO 12185 - Crude petrolelum and petroleum products - - -
Determination of density - Oscillating U-tube
method

ASTM D 1275 - Standard Test Method for Corrosive Sulfur in - -
Electrical Insulating Oils


OECD 201-203 - Test Guidelines for ecotoxicity - -


OECD 301 Guideline for testing of chemicals adopted by - -
European Council


US EPA - Office of Prevention, Pesticides and Toxic - -
Substances (OPPTS)


835.311 - Fate, Transport and Transformation Test - -
Guidelines

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SIST EN 62770:2014



IEC 62770

®


Edition 1.0 2013-11




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Fluids for electrotechnical applications – Unused natural esters for transformers

and similar electrical equipment




Fluides pour applications électrotechniques – Esters naturels neufs pour

transformateurs et matériels électriques analogues
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX Q


ICS 29.040 ISBN 978-2-8322-1191-5



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 62770:2014
– 2 – 62770  IEC:2013
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 9
4 Properties, their significance and test methods . 9
4.1 General . 9
4.2 Physical properties . 9
4.2.1 Appearance . 9
4.2.2 Viscosity . 10
4.2.3 Pour point . 10
4.2.4 Water content . 10
4.2.5 Density . 10
4.3 Electrical properties . 10
4.3.1 Breakdown voltage . 10
4.3.2 Dielectric dissipation factor (DDF) . 10
4.3.3 Relative permittivity (dielectric constant) . 11
4.4 Chemical properties . 11
4.4.1 Acidity . 11
4.4.2 Corrosive sulfur . 11
4.4.3 Additive content . 11
4.4.4 Furfural content . 11
4.5 Performance . 11
4.5.1 Oxidation stability . 11
4.5.2 Total acidity . 12
4.5.3 Viscosity . 12
4.5.4 Dielectric dissipation factor (DDF) . 12
4.6 Health, safety and environmental (HSE) properties . 12
4.6.1 Fire point and flash point . 12
4.6.2 Polychlorinated biphenyls (PCBs) . 12
4.6.3 Biodegradation . 12
4.6.4 Toxicity . 12
5 Classification, identification, general delivery requirements and sampling . 12
5.1 Classification . 12
5.2 Identification and general delivery requirements . 13
5.3 Sampling . 13
Annex A (normative) Summary of the test method for evaluating oxidation stability of
unused natural esters . 15
A.1 Introductory remark . 15
A.2 Test conditions . 15
A.3 Precision . 15
A.4 Relative repeatability (r) . 15
A.5 Relative reproducibility (R) . 15
Annex B (informative) Specifications of low-viscosity insulating fluids derived from
natural esters . 16
Bibliography . 17

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SIST EN 62770:2014
62770  IEC:2013 – 3 –

Table 1 – General specifications . 14
Table A.1 – Relative repeatability and relative reproducibility obtained for different
parameters during RRT . 15
Table B.1 – Specifications for low-viscosity of monoesters derived from natural esters . 16

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SIST EN 62770:2014
– 4 – 62770  IEC:2013
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
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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 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
10/909/FDIS 10/933/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.

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SIST EN 62770:2014
62770  IEC:2013 – 5 –
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.

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SIST EN 62770:2014
– 6 – 62770  IEC:2013
INTRODUCTION
Because of their higher fire points and better environmental compatibility relative to petroleum
derived insulating mineral oil, the use of vegetable oils and other natural esters is on the rise
as insulating and heat transfer fluids in electrical devices such as transformers.
This standard sets performance criteria for unused natural esters earmarked for electrical
applications. However, the use of natural esters is recommended only for equipment that is
not open to the atmosphere, e.g. sealed transformers and reactors because these fluids are
prone to rapid oxidation.
This International Standard does not purport to address all the safety problems associated
with its use. It is the responsibility of the user of the standard to establish appropriate health
and safety practices and determine the applicability of regulatory limitation prior to use.
Unused natural esters which are the subject of this standard should be handled with due
regard to personal hygiene. Direct contact with eyes should be avoided. In case of eye
contact, irrigation with copious amounts of clean running water should be carried out and
medical advice sought.
Performance of some of the tests mentioned in this standard could lead to a hazardous
situation. Attention is drawn to the relevant standard test method for guidance.
The disposal of natural esters, chemicals and sample containers mentioned in this standard
should be carried out in accordance with current national legislation with regard to the impact
on the environment. Every precaution should be taken to prevent the release of natural esters
into the environment.

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SIST EN 62770:2014
62770  IEC:2013 – 7 –
FLUIDS FOR ELECTROTECHNICAL APPLICATIONS –
UNUSED NATURAL ESTERS FOR TRANSFORMERS
AND SIMILAR ELECTRICAL EQUIPMENT


1 Scope
This International Standard describes specifications and test methods for unused natural
esters in transformers and similar oil-impregnated electrical equipment in which a liquid is
required as an insulating and heat transfer medium.
Use of natural esters is not recommended for electrical equipment that is open to the
atmosphere.
In this standard the term “natural esters” applies to insulating fluids for transformers and
similar electrical equipment with suitable biodegradability and environmental compatibility.
Such natural esters are vegetable oils obtained from seeds and oils obtained from other
suitable biological materials and delivered to an agreed point, at a set time period. These oils
are comprised of triglycerides.
Natural esters with additives are within the scope of this standard. Because of their different
chemical composition, natural esters differ from insulating mineral oils and other insulating
fluids that have high fire points, such as synthetic esters or silicone fluids.
Natural, ester-derived insulating fluids with low viscosity have been introduced but are not
covered by this standard. Pertinent properties of such fluids are given in Annex B.
This standard is applicable only to unused natural esters. Reclaimed natural esters and
natural esters blended with non-natural esters fluids are beyond the scope of this standard.
The chemical nomenclature and scientific notations used in the standard are in accordance
with the IUPAC handbook (Quantities, Units and Symbols in Physical Chemistry).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60076-14, Power transformers - Part 14: Liquid-immersed power transformers using high-
temperature insulation materials
IEC 60156, Insulating liquids – Determination of the breakdown voltage at power frequency –
Test method
IEC 60247, Insulating liquids – Measurement of relative permittivity, dielectric dissipation
factor and DC resistivity of insulating fluids
IEC 60296, Fluids for electrotechnical applications – Unused mineral insulating oils for
transformers and switchgear
IEC 60475, Method of sampling liquid dielectrics
IEC 60666, Detection and determination of specific additives in mineral insulating oils

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SIST EN 62770:2014
– 8 – 62770  IEC:2013
IEC 60814, Insulating liquids – Oil-impregnated paper and pressboard – Determination of
water by automatic coulometric Karl Fischer titration
1
IEC 61100, Classification of insulating liquids according to fire-point and net calorific value
IEC 61125:1992, Unused hydrocarbon-based insulating fluids – Test methods for evaluating
the oxidation stability
IEC 61198, Mineral insulating oils – Methods for the determination of 2-furfural and related
compounds
IEC 61619, Insulating liquids – Contamination by polychlorinated biphenyls (PCBs) – Method
of determination by capillary column gas chromatography
IEC 61620, Insulating liquids – Determination of the dielectric dissipation factor by
measurement of the conductance and capacitance – Test method
IEC 62021-3, Insulating liquids – Determination of acidity – Part 3: Test methods for non
2
mineral insulating oils
IEC 62535:2008, Insulating liquids – Test method for detection of potentially corrosive sulfur
in used and unused insulating oils
IEC 62697-1, Test method for quantitative determination of corrosive sulfur compounds in
unused and used insulating liquids – Part 1: Test method for quantitative determination of
dibenzyl disulfide (DBDS)
ISO 2592, Determination of flash and fire point – Cleveland open cup method
ISO 2719, Determination of flash point – Pensky-Martens closed cup method
ISO 3016, Petroleum products – Determination of pour point
ISO 3104, Petroleum products – Transparent and opaque fluids – Determination of kinematic
viscosity and calculation of dynamic viscosity
ISO 3675, Crude petroleum and liquid petroleum products – Laboratory determination of
density – Hydrometer method
ISO 12185, Crude petroleum and petroleum products – Determination of density – Oscillating
U-tube method
ASTM D 1275, Standard Test Method for Corrosive Sulfur in Electrical Insulating Oils
OECD 201-203, Test Guidelines for ecotoxicity
OECD 301, Guideline for testing of chemicals adopted by European Council on July 17th 1992
US EPA, Office of Prevention, Pesticides and Toxic Substances (OPPTS)
835.311, Fate, Transport and Transformation Test Guidelines
—————————
1
 Withdrawn in 2009 and partially replaced by IEC 61039.
2
 To be published.

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SIST EN 62770:2014
62770  IEC:2013 – 9 –
3 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1
additives
suitable chemical substances which are deliberately added to natural ester insulating fluids in
order to improve certain characteristics, e.g. pour point, viscosity, foaming, and oxidation
stability
Note 1 to entry: Examples include antioxidants, pour-point depressants, electrostatic charging tendency
depressant, metal passivator or deactivators, antifoam agent, refining process improver, etc.
3.2
corrosive sulfur
free sulfur and corrosive sulfur compounds detected by subjecting metals such as copper to
contact with an insulating liquid under standardized conditions
[SOURCE: IEC 60050-212:2010, definition 212-18-20, modified – inclusion of "metals such
as"]
3.3
natural esters
vegetable oils obtained from seeds and oils obtained from other suitable biological materials
and comprised of triglycerides
3.4
potentially corrosive sulfur
organo-sulfur compounds present in transformer oils that may cause copper sulfide formation
[SOURCE: IEC 62535:2008, definition 3.1 – modified, the NOTE to entry has been omitted]
3.5
unused natural esters
unused natural esters as delivered by the supplier
Note 1 to entry: Such a liquid has not been used in, nor been in contact with electrical equipment or other
equipment not required for its manufacture, storage or transport.
Note 2 to entry: The manufacturer and supplier of unused natural esters will have taken all reasonable
precautions to ensure that the natural esters are not contaminated with polychlorinated biphenyls, polychlorinated
terphenyls or polycyclic aromatics (PCB,PCT, PCAs,) or corrosive sulfur compounds; used, reclaimed, or
dechlorinated oils, or other contaminants.
4 Properties, their significance and test methods
4.1 General
Salient characteristics of unused natural esters are listed in Table 1.
NOTE Additional information on natural esters for transformers and similar electrical equipment is available in
CIGRE brochure 436 and IEEE report C57.147.
4.2 Physical properties
4.2.1 Appearance
A visual inspection of unused natural esters (with light transmitted through approximately
10 cm thickness of natural esters at ambient temperature) indicates the presence of visible
contaminants, free water and suspended matter.

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SIST EN 62770:2014
– 10 – 62770  IEC:2013
4.2.2 Viscosity
Viscosity influences heat transfer and therefore affects the increase of temperature in the
transformer and other equipment. The lower the viscosity, the easier the oil circulates leading
to better heat transfer. Viscosities at lower temperatures is a critical factor for cold start of
transformers with ON cooling (absence of circulation can lead to possible overheating at hot
spots). It can have negative impact on the speed of moving parts such as on-load tap changer
mechanism, pumps and regulators. Due consideration should be given to viscosity at the
lowest cold start energizing temperature (LCSET). Viscosity at 40 °C and 100 °C shall be
measured according to ISO 3104.
4.2.3 Pour point
Pour point of unused natural esters is the lowest temperature at which the natural esters will
just flow. Pour point shall be measured in accordance w
...