Mineral insulating oils in electrical equipment - Supervision and maintenance guidance

IEC 60422:2013 gives guidance on the supervision and maintenance of the quality of the insulating oil in electrical equipment. This International Standard is applicable to mineral insulating oils, originally supplied conforming to IEC 60296, in transformers, switchgear and other electrical apparatus where oil sampling is reasonably practicable and where the normal operating conditions specified in the equipment specifications apply. This International Standard is also intended to assist the power equipment operator to evaluate the condition of the oil and maintain it in a serviceable condition. It also provides a common basis for the preparation of more specific and complete local codes of practice. The standard includes recommendations on tests and evaluation procedures and outlines methods for reconditioning and reclaiming oil and the decontamination of oil contaminated with PCBs. This fourth edition cancels and replaces the third edition, published in 2005, and constitutes a technical revision. The main changes with respect to the previous edition are as follows:
- This new edition represents a major revision of the third edition, in order to bring in line this standard with latest development of oil condition monitoring, containing new limits for oil parameters, suggested corrective actions in the tables and new test methods.
- The action limits for all oil tests have been revised and changes made where necessary to enable users to use current methodology and comply with requirements and regulations affecting safety and environmental aspects.
- In addition, this standard incorporates changes introduced in associated standards since the third edition was published. The contents of the corrigendum of December 2013 have been included in this copy.

Huiles minérales isolantes dans les matériels électriques - Lignes directrices pour la maintenance et la surveillance

La CEI 60422:2013 donne les lignes directrices pour la surveillance et la maintenance de la qualité des huiles isolantes dans les appareils électriques. La présente norme est applicable aux huiles minérales isolantes, satisfaisant à l'origine aux exigences de la CEI 60296, et présentes dans les transformateurs, appareillages de connexion et appareils électriques similaires, pour lesquels la prise d'échantillons d'huile est possible, et auxquels les conditions normales d exploitation prévues dans les spécifications du matériel sont appliquées. Cette norme est également destinée à aider le personnel d'exploitation à évaluer l'état de l'huile des matériels et à la maintenir en état d'être utilisée. Elle fournit également une base commune à l'élaboration de codes de pratique locaux plus complets et plus spécifiques. La norme inclut des recommandations sur les essais et les procédures d'évaluation, et indique des procédés de retraitement et de régénération de l'huile, et de décontamination de l'huile contaminée par les PCB. Cette quatrième édition annule et remplace la troisième édition, publiée en 2005, et constitue une révision technique. Les modifications principales par rapport à l'édition précédente sont les suivantes:
- Cette nouvelle édition représente une révision importante de la troisième édition, qui a pour objet d'aligner la présente norme sur les derniers développements de la surveillance de l'état de l'huile, contenant de nouvelles limites pour les paramètres relatifs aux huiles, les actions correctives suggérées dans les tableaux et de nouvelles méthodes d'essais.
- Les limites d'action pour tous les essais effectués sur les huiles ont été mises à jour et des changements ont été faits lorsque c'était nécessaire pour permettre à des utilisateurs d'employer la méthodologie courante et de se conformer aux exigences et aux règlements affectant la sécurité et les aspects environnementaux.
- Cette norme incorpore, également, les modifications introduites dans les normes associées depuis que la troisième édition a été publiée. Le contenu du corrigendum de décembre 2013 a été pris en considération dans cet exemplaire.

General Information

Status
Published
Publication Date
09-Jan-2013
Current Stage
PPUB - Publication issued
Start Date
10-Jan-2013
Completion Date
10-Jan-2013
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IEC 60422
Edition 4.0 2013-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Mineral insulating oils in electrical equipment – Supervision and maintenance
guidance
Huiles minérales isolantes dans les matériels électriques – Lignes directrices
pour la maintenance et la surveillance
IEC 60422:2013
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60422
Edition 4.0 2013-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Mineral insulating oils in electrical equipment – Supervision and maintenance
guidance
Huiles minérales isolantes dans les matériels électriques – Lignes directrices
pour la maintenance et la surveillance
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX X
ICS 29.040.10 ISBN 978-2-83220-560-0

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
---------------------- Page: 3 ----------------------
– 2 – 60422  IEC:2013
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope ............................................................................................................................... 8

2 Normative references ....................................................................................................... 8

3 Terms and definitions ....................................................................................................... 9

4 Properties and deterioration/degradation of oil ............................................................... 10

5 Oil tests and their significance ........................................................................................ 11

5.1 General ................................................................................................................. 11

5.2 Colour and appearance ......................................................................................... 12

5.3 Breakdown voltage ................................................................................................ 12

5.4 Water content ........................................................................................................ 12

5.4.1 General ..................................................................................................... 12

5.4.2 Water in oil ................................................................................................ 12

5.4.3 Water content in the oil/paper-system ........................................................ 14

5.4.4 Interpretation of results.............................................................................. 15

5.5 Acidity ................................................................................................................... 15

5.6 Dielectric dissipation factor (DDF) and resistivity ................................................... 15

5.7 Inhibitor content and oxidation stability .................................................................. 18

5.7.1 Oxidation stability ...................................................................................... 18

5.7.2 Monitoring of uninhibited oils ..................................................................... 18

5.7.3 Monitoring of inhibited oils ......................................................................... 18

5.8 Sediment and sludge ............................................................................................. 18

5.9 Interfacial tension (IFT) ......................................................................................... 19

5.10 Particle count ........................................................................................................ 19

5.11 Flash point ............................................................................................................ 19

5.12 Compatibility of insulating oils ............................................................................... 20

5.13 Pour point ............................................................................................................. 20

5.14 Density .................................................................................................................. 20

5.15 Viscosity................................................................................................................ 20

5.16 Polychlorinated biphenyls (PCBs) .......................................................................... 21

5.17 Corrosive sulphur .................................................................................................. 21

5.18 Dibenzyl disulphide (DBDS) .................................................................................. 22

5.19 Passivator ............................................................................................................. 22

6 Sampling of oil from equipment ...................................................................................... 22

7 Categories of equipment ................................................................................................. 23

8 Evaluation of mineral insulating oil in new equipment ..................................................... 23

9 Evaluation of oil in service .............................................................................................. 24

9.1 General ................................................................................................................. 24

9.2 Frequency of examination of oils in service ........................................................... 25

9.3 Testing procedures ................................................................................................ 26

9.3.1 General ..................................................................................................... 26

9.3.2 Field tests.................................................................................................. 26

9.3.3 Laboratory tests ........................................................................................ 27

9.4 Classification of the condition of oils in service ...................................................... 27

9.5 Corrective action ................................................................................................... 27

---------------------- Page: 4 ----------------------
60422  IEC:2013 – 3 –

10 Handling and storage ..................................................................................................... 32

11 Treatment ....................................................................................................................... 33

11.1 WARNING ............................................................................................................. 33

11.2 Reconditioning ...................................................................................................... 34

11.2.1 General ..................................................................................................... 34

11.2.2 Reconditioning equipment ......................................................................... 35

11.2.3 Application to electrical equipment ............................................................ 36

11.3 Reclaiming ............................................................................................................ 37

11.3.1 General ..................................................................................................... 37

11.3.2 Reclaiming by percolation .......................................................................... 37

11.3.3 Reclaiming by contact ............................................................................... 38

11.3.4 Renewal of additives ................................................................................. 38

11.4 Decontamination of oils containing PCBs .............................................................. 38

11.4.1 General ..................................................................................................... 38

11.4.2 Dehalogenation processes using sodium and lithium derivatives ............... 38

11.4.3 Dehalogenation processes using polyethylene glycol and potassium

hydroxide (KPEG) ...................................................................................... 39

11.4.4 Dehalogenation in continuous mode by closed circuit process ................... 39

12 Replacement of oil in electrical equipment ...................................................................... 39

12.1 Replacement of oil in transformers rated below 72,5 kV and in switchgear

and associated equipment ..................................................................................... 39

12.2 Replacement of oil in transformers rated 72,5 kV and above ................................. 39

12.3 Replacement of oil in electrical equipment contaminated with PCB ........................ 40

13 Passivation ..................................................................................................................... 40

Annex A (informative) Evaluating water in oil and insulation................................................. 41

Annex B (informative) Particles ............................................................................................ 43

Annex C (informative) Test method for determination of sediment and sludge ...................... 44

Bibliography .......................................................................................................................... 45

Figure 1 – Example of variation in saturation water content with oil temperature and

acidity for insulating oil originally conforming to IEC 60296 ................................................... 14

Figure 2 – Example of variation of resistivity with temperature for insulating oils ................... 17

Figure A.1 – Typical correction factors .................................................................................. 41

Table 1 – Tests for in-service mineral insulating oils ............................................................. 11

Table 2 – Categories of equipment ....................................................................................... 23

Table 3 – Recommended limits for mineral insulating oils after filling in new electrical

equipment prior to energization ............................................................................................. 24

Table 4 – Recommended frequency of testing .................................................................... 26

Table 5 – Application and interpretation of tests (1 of 4) ....................................................... 28

Table 6 – Summary of typical actions .................................................................................... 32

Table 7 – Conditions for processing inhibited and/ or passivator containing mineral

insulating oils ........................................................................................................................ 35

Table A.1 – Guidelines for interpreting data expressed in per cent saturation ....................... 42

Table B.1 – Typical contamination levels (particles) encountered on power transformer

insulating oil as measured using IEC 60970 .......................................................................... 43

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– 4 – 60422  IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MINERAL INSULATING OILS IN ELECTRICAL EQUIPMENT –
SUPERVISION AND MAINTENANCE GUIDANCE
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 60422 has been prepared by IEC technical committee 10: Fluids

for electrotechnical applications.

This fourth edition cancels and replaces the third edition, published in 2005, and constitutes a

technical revision.
The main changes with respect to the previous edition are as follows:

This new edition represents a major revision of the third edition, in order to bring in line this

standard with latest development of oil condition monitoring, containing new limits for oil

parameters, suggested corrective actions in the tables and new test methods.

The action limits for all oil tests have been revised and changes made where necessary to

enable users to use current methodology and comply with requirements and regulations

affecting safety and environmental aspects.
---------------------- Page: 6 ----------------------
60422  IEC:2013 – 5 –

In addition, this standard incorporates changes introduced in associated standards since the

third edition was published.
The text of this standard is based on the following documents:
FDIS Report on voting
10/894/FDIS 10/896/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.

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.

The contents of the corrigendum of December 2013 have been included in this copy.

---------------------- Page: 7 ----------------------
– 6 – 60422  IEC:2013
INTRODUCTION

Insulating mineral oils are used in electrical equipment employed in the generation,

transmission, distribution and use of electrical energy, so that the amount of oil in service,

worldwide, amounts to hundreds of millions of kilograms.

Monitoring and maintaining oil quality is essential to ensure the reliable operation of oil-filled

electrical equipment. Codes of practice for this purpose have been established by electrical

power authorities, power companies and industries in many countries.

A review of current experience reveals a wide variation of procedures and criteria. It is

possible, however, to compare the value and significance of standardized oil tests and to

recommend uniform criteria for the evaluation of test data.

If a certain amount of oil deterioration (by degradation or contamination) is exceeded, there is

inevitably some erosion of safety margins and the question of the risk of premature failure

should be considered. While the quantification of the risk can be very difficult, a first step

involves the identification of potential effects of increased deterioration. The philosophy

underlying this standard is to furnish users with as broad a base of understanding of oil

quality deterioration as is available, so that they can make informed decisions on inspection

and maintenance practices.

Unused mineral oils are limited resources and should be handled with this in mind. Used

mineral oils are, by most regulations, deemed to be controlled waste. If spills occur this may

have a negative environmental impact especially if the oil is contaminated by persistent

organic pollutants such as polychlorinated biphenyls (PCBs).

This International Standard, whilst technically sound, is mainly intended to serve as a

common basis for the preparation of more specific and complete codes of practice by users in

the light of local circumstances. Sound engineering judgement will have to be exerted in

seeking the best compromise between technical requirements and economic factors.
Reference should also be made to instructions from the equipment manufacturer.
General caution

This International Standard does not purport to address all the safety problems associated

with its use. It is the responsibility of the user of this standard to establish appropriate health

and safety practices and determine the applicability of regulatory limitations prior to use.

The mineral oils and oil additives which are the subject of this standard should be handled

with due regard to personal hygiene. Direct contact with the eyes may cause slight irritation.

In the case of eye contact, irrigation with copious quantities of clean running water should be

carried out and medical advice sought. For more information, refer to the safety data sheet

provided by the manufacturer. Some of the tests specified in this standard involve the use of

processes that could lead to a hazardous situation. Attention is drawn to the relevant standard

for guidance.
Environment

This standard is applicable to mineral oils, chemicals and used sample containers.

Attention is drawn to the fact that, at the time of writing this standard, some mineral oils in

service are known to be contaminated to some degree by PCBs.
---------------------- Page: 8 ----------------------
60422  IEC:2013 – 7 –

Because of this, safety countermeasures should be taken to avoid risks to workers, the public

and the environment during the life of the equipment, by strictly controlling spills and

emissions. Disposal or decontamination of these oils should be carried out strictly according

to local regulations. Every precaution should be taken to prevent release of mineral oil into

the environment.
---------------------- Page: 9 ----------------------
– 8 – 60422  IEC:2013
MINERAL INSULATING OILS IN ELECTRICAL EQUIPMENT –
SUPERVISION AND MAINTENANCE GUIDANCE
1 Scope

This International Standard gives guidance on the supervision and maintenance of the quality

of the insulating oil in electrical equipment.

This standard is applicable to mineral insulating oils, originally supplied conforming to

IEC 60296, in transformers, switchgear and other electrical apparatus where oil sampling is

reasonably practicable and where the normal operating conditions specified in the equipment

specifications apply.

This standard is also intended to assist the power equipment operator to evaluate the

condition of the oil and maintain it in a serviceable condition. It also provides a common basis

for the preparation of more specific and complete local codes of practice.

The standard includes recommendations on tests and evaluation procedures and outlines

methods for reconditioning and reclaiming oil and the decontamination of oil contaminated

with PCBs.

NOTE The condition monitoring of electrical equipment, for example by analysis of dissolved gases, furanic

compounds or other means, is outside the scope of this standard.
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 60156, Insulating liquids – Determination of the breakdown voltage at power frequency –

Test method

IEC 60247, Insulating liquids – Measurement of relative permittivity, dielectric dissipation

factor (tan δ) and d.c. resistivity

IEC 60296:2012, Fluids for electrotechnical applications – Unused mineral insulating oils for

transformers and switchgear
IEC 60475, Method of sampling liquid dielectrics

IEC 60666:2010, Detection and determination of specified additives in mineral insulating oils

IEC 60814, Insulating liquids – Oil-impregnated paper and pressboard – Determination of

water by automatic coulometric Karl Fischer titration
IEC 60970, Insulating liquids – Methods for counting and sizing particles

IEC 61125:1992, Unused hydrocarbon based insulating liquids – Test methods for evaluating

the oxidation stability
---------------------- Page: 10 ----------------------
60422  IEC:2013 – 9 –

IEC 61619, Insulating liquids – Contamination by polychlorinated biphenyls (PCBs) – Method

of determination by capillary column gas chromatography

IEC 62021-1, Insulating liquids – Determination of acidity – Part 1: Automatic potentiometric

titration

IEC 62021-2, Insulating liquids – Determination of acidity – Part 2: Colourimetric titration

IEC 62535:2008, Insulating liquids – Test method for detection of potentially corrosive sulphur

in used and unused insulating oils

IEC 62697-1:2012, Test methods for quantitative determination of corrosive sulfur compounds

in unused and used insulating liquids - Part 1: Test method for quantitative determination of

dibenzyldisulfide (DBDS)
ISO 2049, Petroleum products – Determination of colour (ASTM scale)
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 – Hydrometer method

ISO 4406:1999, Hydraulic fluid power – Fluids – Method for coding the level of contamination

by solid particles

EN 14210, Surface active agents – Determination of interfacial tension of solutions of surface

active agents by the stirrup or ring method

ASTM D971, Standard Test Method for Interfacial Tension of Oil Against Water by the Ring

Method

ASTM D1275:2006, Standard Test Method for Corrosive Sulfur in Electrical Insulating Oils

DIN 51353: Testing of insulating oils; Detection of corrosive sulphur; Silver strip test

3 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1
local regulations
regulations pertinent to the particular process in the country concerned

Note 1 to entry: Such regulations may be defined by local, regional or national legislation or even the owner or

operator of the equipment itself. They are always to be considered as the most stringent of any combina

...

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