Individual and more sensitive DGA interpretation values

The analysis of the dissolved gases in oil is one of the most important methods of condition assessment for power transformers. Its analysis is based in first step on the evaluation if the actual result shows a typical behaviour. Therefore in the corresponding standards and in further literature so called 90 % values are given which indicate a typical behavior. To sensitize this first evaluation and to enable a more individualized comparative values this contribution describes typical groups of transformers and their typical behavior based on a big transformer fleet with more than 16 thousand transformers, each with one or more oil samples.