IEC 62975:2021 pdf download.Natural esters - Guidelines for maintenance and use in electrical equipment
1 Scope
This document provides procedures and guidelines that are intended for the use and maintenance of natural ester liquid in sealed transformers and other electrical equipment.
This document is applicable to natural esters, originally supplied conforming to IEC 62770 and other applicable standards (e.g. ASTM D6871 [1]1) in transformers, switchgear and electrical apparatus where liquid sampling is practical and where the normal operating conditions specified in the equipment specifications apply.
At present, there is a limited amount of information available for electrical equipment other than transformers.
This document is also intended to assist the power equipment operator to evaluate the condition of the natural ester 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 document includes recommendations on tests and evaluation procedures and outlines methods for reconditioning and reclaiming the liquid, when necessary.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. 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一Determination of the breakdown voltage at power frequency - Test method
IEC 60247，Insulating liquids - Measurement of relative permittivity, dielectric dissipation factor (tan 5) and d.c. resistivity
IEC 60422:2013，Mineral insulating oils in electrical equipment - Supervision and maintenance guidance
IEC 60475, Method of sampling insulating liquids
IEC 60567，Oil-filled electrical equipment - Sampling of gases and analysis of free and dissolved gases一Guidance
IEC 60666, 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，Insulating liquids - Test methods for oxidation stability. Test method for evaluating the oxidation stability of insulating liquids in the delivered state
IEC 62021-3, Insulating liquids - Determination of acidity - Part 3: Test methods for non - mineral insulating oils
IEC 62770, Fluids for electrotechnical applications - Unused natural esters for transformers and similar electrical equipment
IEC 62961, Insulating liquids - Test methods for the determination of interfacial tension of insulating liquids - Determination with the ring method
ISO 2049, Petroleum products - Determination of colour (ASTM scale)
ISO 2592, Petroleum products - Determination of flash and fire points - Cleveland open cup method
ISO 3016, Petroleum and related products from natural or synthetic sources - Determination of pour point
ISO 3104, Petroleum products - Transparent and opaque liquids一Determination of kinematic viscosity and calculation of dynamic viscosity.IEC 62975 pdf download.