Improvement in Diagnostic Method for Transformer based on Dissolved Gas Analysis

Abstract

The maintenance control of oil-immersed transformer based on dissolved gas analysis of insulation oil is carried out according to the Electric Technology Research Association report “The maintenance control of oil-immersed transformer". According to this diagnostic method, it is possible to discriminate between discharge mode and overheating mode. But in the overheating mode, it is difficult to judge the abnormality of an iron core group and the one of a winding group exactly. As for the cause of the gas occurrence of the overheat mode, the wrong point of the iron core occupies most. However, it has the difficulty of the countermeasure in the maintenance spot. Because it had to cope with it urgently when there was a wrong point in the winding group.
So, we did the experiment of the gas occurrence using actual models of winding and iron core, and could know the characteristics of the gas occurrence. The estimated precision improvement of the overheating point inside the transformer could be attempted, by adding the way of diagnosing which these characteristics were used for to the Electric Technology Research Association method.