scope:

This guide applies to mineral oil-immersed transformers and addresses:

a) The theory of combustible gas generation in a transformer

b) The interpretation of gas analysis

c) Suggested operating procedures

d) Various diagnostic techniques, such as Key Gases, Rogers Ratios, Duval Triangle, and other methods

e) Case studies and examples

f) Evaluation criteria and guidelines

g) A bibliography of related literature

Purpose

The purpose of this document is to provide a guide for evaluating dissolved gases analysis results from mineral oil-immersed transformers using statistical based analytical tools and fault interpretation methods.