TPD - Fluids for electrotechnical applications

This document provides specifications and test methods for unused and recycled mineral
insulating oils (see Clause 3 for definitions). It applies to mineral oil delivered according to the
contractual agreement, intended for use in transformers, switchgear and similar electrical
equipment in which oil is required for insulation and heat transfer. Both unused oil and
recycled oil under the scope of this document have not been used in, nor been in contact with
electrical equipment or other equipment not required for manufacture, storage or transport.
Unused oils are obtained by refining, modifying and/or blending of petroleum products and
other hydrocarbons from virgin feedstock.
Recycled oils are produced from oils previously used as mineral insulating oils in electrical
equipment that have been subjected to re-refining or reclaiming (regeneration) by processes
employed offsite. Such oils will have originally been supplied in compliance with a recognized
unused mineral insulating oil specification. This document does not differentiate between the
methods used to recycle mineral insulating oil. Oils treated on-site (see IEC 60422) are not
within the scope of this document.
Oils with and without additives are both within the scope of this document.
This document does not apply to mineral insulating oils used as impregnating medium in
cables or capacitors.

This Standard defines requirements for the characterization of unused modified esters or blends of unused esters used as insulating liquids for electrotechnical applications. It does not cover liquids that contain any proportion of used liquids. The liquids covered by this document are intended mainly for transformer applications. Unused modified/synthetized esters are derived from a natural or synthetic base, or are blends of both. This document covers a variety of ester liquids not covered by other standards specific to natural esters (IEC 62770) or synthetic esters (IEC 61099). As it addresses various categories of liquids, this document also covers a wide range of values for certain performance characteristics. An important property is viscosity, which can affect the design and cooling performance of electrical equipment. A categorization is defined based on the kinematic viscosity of the different liquids. The category of low viscosity ester liquids is established.

This document provides criteria for the re-use of sulphur hexafluoride (SF6) and its mixtures
after recovery and reclaiming from electrical equipment (e.g. for maintenance, at the end-oflife).
Sulphur hexafluoride (SF6), nitrogen (N2) and carbon tetrafluoride (CF4), are gases commonly
used for electrical equipment. Taking into account environmental concerns, particular
attention is paid to re-use criteria for SF6 and its mixtures with N2 and CF4 for its use in
electrical equipment. Procedures for recovering and reclaiming used SF6 and its mixtures are
outside the scope of this document and are described in IEC 62271-4.
This document provides several annexes on the description of the different methods of
analysis, on by-products, on the procedure for evaluating the potential health effects from byproducts,
on cryogenic reclaiming of SF6, and on reclaiming recommendations.
Storage, transportation and disposal of SF6 and its mixtures are outside the scope of this
document and are covered by IEC 62271-4. Procedures to determine SF6 leakages are
described in IEC 60068-2-17 [4]1.
For the purposes of this document, the complementary gases used in SF6 mixtures will be
limited to N2 or CF4.

This document establishes the measurement of the interfacial tension between insulating
liquid and water by means of the Du Noüy ring method close to equilibrium conditions. In
order to obtain a value that provides a realistic expression of the real interfacial tension, a
measurement after a surface age of approximately 180 s is recorded.

This document defines the quality for technical grade sulphur hexafluoride (SF6) and
complementary gases such as nitrogen (N2) and carbon tetra-fluoride (CF4), for use in
electrical equipment. Detection techniques, covering both laboratory and in-situ
portable instrumentation, applicable to the analysis of SF6, N2 and CF4 gases prior to the
introduction of these gases into the electrical equipment are also described in this document.
This document provides some information on sulphur hexafluoride in Annex A and on the
environmental effects of SF6 in Annex B.
Information about SF6 by-products and the procedure for evaluating the potential effects of
SF6 by-products on human health are covered by IEC 60480, their handling and disposal
being carried out according to international and local regulations with regard to the impact on
the environment. Handling of SF6 and its mixtures is covered by IEC 62271-4.
Procedures to determine SF6 leakages are described in IEC 60068-2-17.
For the purposes of this document, the complementary gases used in SF6 mixtures will be
limited to N2 or CF4.

This document describes a test method for evaluating the oxidation stability of insulating
liquids in the delivered state under accelerated conditions regardless of whether or not
antioxidant additives are present. The duration of the test can be different depending on the
insulating liquid type and is defined in the corresponding standards (e.g. in IEC 60296,
IEC 61099, IEC 62770). The method can be used for measuring the induction period, the test
being continued until the volatile acidity significantly exceeds 0,10 mg KOH/g in the case of
mineral oils. This value can be significantly higher in the case of ester liquids.
The insulating liquid sample is maintained at 120 °C in the presence of a solid copper catalyst
whilst bubbling air at a constant flow. The degree of oxidation stability is estimated by
measurement of volatile acidity, soluble acidity, sludge, dielectric dissipation factor, or from
the time to develop a given amount of volatile acidity (induction period with air).
In informative Annex B, a test method for evaluating the oxidation stability of inhibited mineral
insulating oils in the delivered state by measurement of the induction period with oxygen is
described. The method is only intended for quality control purposes. The results do not
necessarily provide information on the performance in service. The oil sample is maintained
at 120 °C in the presence of a solid copper catalyst whilst bubbling through a constant flow of
oxygen. The degree of oxidation stability is estimated by the time taken by the oil to develop a
determined amount of volatile acidity (induction period with oxygen). Additional criteria such
as soluble and volatile acidities, sludge and dielectric dissipation factor can also be
determined after a specified duration.
In informative Annex C, a test method intended to simulate the thermo-oxidative behaviour of
ester insulating liquids (headspace of air at 150 °C for 164 h) is described.
Additional test methods such as those described in IEC TR 62036 based on differential
scanning calorimetry can also be used as screening tests, but are out of the scope of this
document.

This International Standard describes how the concentrations of dissolved gases or free
gases may be interpreted to diagnose the condition of oil-filled electrical equipment in service
and suggest future action.
This standard is applicable to electrical equipment filled with mineral insulating oil and
insulated with cellulosic paper or pressboard-based solid insulation. Information about
specific types of equipment such as transformers (power, instrument, industrial, railways,
distribution), reactors, bushings, switchgear and oil-filled cables is given only as an indication
in the application notes (see Annex A).
This standard may be applied, but only with caution, to other liquid-solid insulating systems.
In any case, the indications obtained should be viewed only as guidance and any resulting
action should be undertaken only with proper engineering judgment.

This International Standard covers specifications and test methods for unused silicone liquids
intended for use in transformers and other electrotechnical equipment.
The specified characteristics of silicone transformer liquid classified as L-NTUK-8360300 (in
accordance with IEC 61039) are described in Table 1.
Besides the standard transformer applications there are other applications of silicone liquids,
such like cable accessories, capacitors, electrical magnets etc. The specified characteristics
and minimum requirements for these liquids are described in Table 2.
NOTE Maintenance of used silicone liquid in electrotechnical equipment is covered in a separate publication
IEC 60944.

This part of IEC 62021 describes two procedures for the determination of the acidity of
unused and used electrical non-mineral insulating oils. Method A is potentiometric titration
and Method B is colourimetric titration.
NOTE 1 In unused and used non-mineral insulating oils, the constituents that may be considered to have acidic
characteristics include organic acids, phenolic compounds, some oxidation products, resins, organometallic salts
and additives.
The method may be used to indicate relative changes that occur in non-mineral insulating oil
during use under oxidizing conditions regardless of the colour or other properties of the
resulting non-mineral oil.
The acidity can be used in the quality control of unused non-mineral insulating oil.
As a variety of oxidation products present in used non-mineral insulating oil contribute to
acidity and these products vary widely in their corrosion properties, the test cannot be used to
predict corrosiveness of non-mineral insulating oil under service conditions.
NOTE 2 The acidity results obtained by potentiometric test method may or may not be numerically the same as
those obtained by colourimetric methods, but they are generally of the same magnitude.

This International Standard specifies requirements for recycled mineral insulating oils
intended for use in transformers, switchgear, and similar electrical equipment in which oil is
required for insulation and heat transfer.
These oils are produced by processes employed offsite.
Oils treated and reconditioned on-site are not within the scope of this standard.
Oils with and without additives are within the scope of this standard.
Such oils will have originally been supplied in compliance with a recognized unused mineral
insulating oil specification.
This standard does not differentiate between the methods used to recycle mineral insulating
oil.
This standard does not apply to mineral insulating oils used as impregnates in cables or
capacitors.
For the purpose of this standard the following subclauses of IEC 60296:2012 apply:
– 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9;
– 4.1, 4.3, 4.4;
– 5.1, 5.5;
– 6.1, 6.2, 6.4, 6.5, 6.6, 6.8, 6.9, 6.10, 6.11.1, 6.11.3, 6.11.4, 6.12, 6.14, 6.15, 6.16;
– 7.1.
NOTE Some types of re-refined oils are equivalent to unused oils in terms of performance, in which case IEC
60296 is applicable. This should be stated by the manufacturer.

EN IEC 62770 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).

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.

This part of IEC 62697 specifies a test method for the quantitative determination of corrosive sulfur compounds-dibenzyl disulfide (DBDS) in used and unused insulating liquids over a 5 - 600 mg kg-1 concentration range.

This International Standard specifies oil-sampling procedures, analysis requirements and procedures, and recommends sensitivity, repeatability and accuracy criteria for the application of dissolved gas analysis (DGA) to factory testing of new power transformers, reactors and instrument transformers filled with mineral insulating oil when DGA testing has been specified. The most effective and useful application of DGA techniques to factory testing is during the performance of long-term tests, typically temperature-rise (heat run) and overloading tests on power transformers and reactors, also impulse tests on instrument transformers. DGA may also be valuable for over-excitation tests run over an extended period of time. Experience with DGA results, before and after short-time dielectric tests, indicates that DGA is normally less sensitive than electrical and acoustic methods for detecting partial discharges. However, DGA will indicate when these partial discharges become harmful to the insulation and may be detected by inspection.

Will supersede EN 60296:2004

Will supersede EN 60567:2005

IEC 60475:2011 is applicable to the procedure to be used for insulating liquids in delivery containers and in electrical equipment such as power and instrument transformers, reactors, bushings, oil-filled cables, oil-filled tank-type capacitors, switchgear and load tap changers. The main changes with respect to the previous edition are as follows: - withdrawal of askarels; - addition of recommendations concerning general health, safety and environmental protection; - additional details regarding the sampling of oil from electrical equipment, using various types of sampling devices appropriate for the different types of oil tests to be performed in the laboratory.

This International Standard covers the specification and test methods for unused synthetic organic esters. It applies to synthetic organic esters, delivered to the agreed point and time of delivery intended, for use in transformers, switchgear and similar related equipment in which synthetic organic esters are required as an insulant and for heat transfer. These unused synthetic organic esters are obtained by chemical processing and physical treatments of fatty acids and polyols.

The methods described in this International Standard concern the detection and determination of specified additives in unused and used mineral insulating oils. The detection methods may be applied to assess whether or not a mineral insulating oil contains an additive as specified by the supplier. The determination methods are used for the quantitative determination of additives known to be present or previously detected by the appropriate detection method.

This International Standard specifies oil-sampling procedures, analysis requirements and procedures, and recommends sensitivity, repeatability and accuracy criteria for the application of dissolved gas analysis (DGA) to factory testing of new power transformers, reactors and instrument transformers filled with mineral insulating oil when DGA testing has been specified. The most effective and useful application of DGA techniques to factory testing is during the performance of long-term tests, typically temperature-rise (heat run) and overloading tests on power transformers and reactors, also impulse tests on instrument transformers. DGA may also be valuable for over-excitation tests run over an extended period of time. Experience with DGA results, before and after short-time dielectric tests, indicates that DGA is normally less sensitive than electrical and acoustic methods for detecting partial discharges. However, DGA will indicate when these partial discharges become harmful to the insulation and may be detected by inspection.

The scope of this Technical report is to provide guidance for the activities of inventory, control, management, decontamination and/or disposal of equipment and containers with insulating liquid containing PCBs, in compliance with the Council Directives (96/59/EC), using Best Available Techniques - BAT - (96/61/EC), Commission Decision (2001/68/EC), Stockholm Convention on Persistent Organic Pollutants (POPs) and/or with appropriate national or local legislation. This Technical report is addressed, in particular, toward the Life Cycle Management (LCM) of insulating liquids and it has been developed in accordance with the following objectives:
a) reduction of risks for workers, public health and the environment, arising from human error, malfunction, or failures of the equipment that could cause fires or spillage of hazardous and Persistent Organic Pollutants (POPS)s;
b) implementation of the “Best Available Techniques” (BAT),”Best Environmental Practices”(BEP)and methodologies available for safety, whilst taking into account the surroundings and the criteria of self-sufficiency and functional recovery;
c) technical feasibility of the activities within the prescribed time schedules, taking into account current legislation and economic feasibility.
NOTE 1 For those CENELEC countries in which the European Directives do not apply, this Technical report has an informative purpose only. Different limits from those given in the present Technical report are required in some countries.
NOTE 2 For those countries outside of European Community the Stockholm Convention on Persistent Organic Pollutants (POPs) should be applied.
NOTE 3 When reading this Technical report, reference should also be made to Annex C of EN 50195 and Annex B of EN 50225, because in some EU countries (i.e. France, Italy, Poland, Spain, etc.) there are other mandatory requirements.

This part of IEC 62024 specifies the measuring methods of the rated direct current limits for small inductors. Standardized measuring methods for the determination of ratings enable users to accurately compare the current ratings given in various manufacturers' data books. This standard is applicable to leaded and surface mount inductors with dimensions according to IEC 62025-1 and generally with rated current less than 22 A, although inductors with rated current greater than 22 A are available that fall within the dimension restrictions of this standard (no larger than 12 mm × 12 mm footprint approximately). These inductors are typically used in DC to DC converters built on PCB, for electric and telecommunication equipment, and small size switching power supply units. The measuring methods are defined by the saturation and temperature rise limitations induced solely by direct current. Normative references. The following referenced documents are indispens.

This International Standard establishes the detailed classification of the N family (insulating liquids) that belongs to class L (lubricants, industrial oils and related products) in accordance with ISO 8681 and ISO 6743-99, affecting product categories that include products derived from petroleum processing, synthetic chemical products and synthetic and natural esters.

This standard describes the sampling procedures and methods for the determination of particle concentration and size distribution. Three methods are specified. One uses an automatic particle size analyser, working on the light interruption principle. The other two use an optical microscope, in either the transmitted light or incident light mode, to count particles collected on the surface of a membrane filter. The optical microscope methods are described in ISO 4407. All three methods are applicable to both used and unused insulating liquids. Annex A contains an alternative sampling procedure using a syringe and Annex B reports a reference for the calibration of automatic particle counters.

This part of IEC 62021 describes a procedure for determination of the acidity of unused and used electrical mineral insulating oils.The method may be used to indicate relative changes that occur in a mineral insulating oil during use under oxidizing conditions that may or may not be shown by other properties of the resulting mineral oil. The acidity can be used in the quality control of unused mineral oil. As a variety of oxidation products present in used mineral oil contribute to acidity and these products vary widely in their corrosion properties, the test cannot be used to predict corrosiveness of a mineral oil under service conditions.

This International Standard defines the quality  requirements and properties for technical  grade sulfur hexafluoride (SF6) for use in  electrical equipment. It covers the properties  and methods of test applicable to SF6 when  this substance is supplied for use in  connection with any electrical equipment. This  second edition differs widely from the first one.  The focus is now on the specification of the  gas needed for electrical applications. As a  consequence, the term employed to name  this gas is "technical grade" in place of "new".  Based on experience, the acceptable impurity  levels have been increased. However, the gas  as defined in this new second edition has the  same performance in electrical equipment as  the gas previously defined in the first edition.  The analytical methods for the SF6 analysis  have been removed as it has been found  confusing to prescribe methods that can  become obsolete very rapidly.

Supersedes HD 565 S1:1993

Concerns the re-use of sulfur hexafluoride (SF6) after removal from electrical equipment (for maintenance, or at the end of life). This standard recommends procedures for reclaiming used SF6 and for restoring its quality to an acceptable level, which would allow the filling of new or existing electrical equipment. This standard provides guidance to operational and maintenance personnel for the testing and safe handling of used SF6 . The main changes with respect to the previous edition are listed below: - updating of standard as it relates to environmental issues, storage and analytical methods; - addition of specification for the re-use of gas; - inclusion of a regeneration process for sulfur hexafluoride taken from electrical equipment.

Specifies the characteristics of unused triaryl phosphate ester fluids for turbine governor controls and other hydraulic systems in electrical power stations. Fluids used in this application are classified under category TCD of ISO 6743-5. The major changes with regard to the first edition concern the need to upgrade the report to an International Standard, taking account of changes to the specification. The changes made include: a) introduction of new tests to define fire resistance, namely the Manifold Ignition and Wick flame persistence tests; b) flame persistence tests; c) introduction of a pour point requirement; d) a change to the Sequence II foaming requirement; e) introduction of a cleanliness requirement; f) introduction of an elastomer compatibility requirement; g) use of ISO test methods equivalent ot the original DIN tests.

Describes methods for the determination of the dielectric dissipation factor, relative permittivity and d.c. resistivity of any insulating liquid material at the test temperature. The methods are primarily intended for making reference tests on unused liquids. They can also be applied to liquids in service in transformers, cables and other electrical apparatus. However the method is applicable to a single phase liquid only. When it is desired to make routine determinations, simplified procedures, as described in Annex C, may be adopted. With insulating liquids other than hydrocarbons, alternative cleaning procedures may be required. The main changes from the previous edition deal with the preferred measurement method.

D114/118: CLC/BTWG 99-1 disbanded

D114/118: CLC/BTWG 99-1 disbanded

Covers specifications and test methods for unused mineral insulating oils, as delivered, intended for use in cables with oil ducts. These include hollow core cables, pipe type cables and any others in which provision is made for the oil to flow.

EN following parallel vote

Supersedes HD 397 S1:1979

EN following parallel vote

Covers specifications and test methods for unused polybutenes, as delivered, intended for use as insulating liquids in electrical equipment.

Describes two procedures each using different apparatus to measure the tendency of insulating liquids to evolve or absorb gas when subjected to electrical stress.

Gives the detection methods for the anti-oxidant additives in hydrocarbon insulating oils as well as determination methods of these additives.

D83/038: Document CLC/TC 64B(AT)9 to be considered

EN following parallel vote * Supersedes HD 487 S1

EN following parallel vote

EN following parallel vote

Describes a method for assessing the changes in activity of pour point depressant additives in inhibited and uninhibited mineral insulating oils when aged in the presence of insulating kraft paper.

EN following parallel vote * Corrigendum to EN issued December 1993

EN following parallel vote

EN following parallel vote

EN following parallel vote

EN following parallel vote * Supersedes HD 497 S1