Standards Development

Scope

 The purpose of this guide is to assist the transformer operator in evaluating dissolved gas analysis (DGA) data obtained from natural ester acc. IEC 62770 and synthetic ester acc. to IEC 61099-filled transformers and similar equipment. Due to limited information on equipment filled with mono- and blended esters (IEC 63012) at present  they are included in the informative Annex H.Ester liquids are present in the whole range of applications including transport and distribution networks, industrial, traction, wind and solar transformers as reflected in the database. Nowadays their use has been extended to power transformers. This guide includes the following: Gas generation in a natural and synthetic ester-filled transformer DGA Interpretation methods (fault type identification and gas levels and comparison with those for mineral oils) Gas concentration guide values valid for the use of DGA interpretation tools Interpretation of the dissolved gas analysis results. Recommended actions based on the interpretation of dissolved gas analysis results. Examples of faulty equipment The indications obtained should be viewed only as a guidance and any resulting action should be taken with a proper engineering judgement.