Recent Development in DGA Diagnosis Using Graphical Analysis Method

Abstract

As one of the main equipment in an electric power system, transformer’s failure is very important to be avoided to maintain the continuity of the distribution of electric power. One of the most crucial diagnosis method that has been practiced widely for transformer is Dissolve Gas Analysis (DGA). Many studies have been done to develop the DGA method to determine the type of faults that occur in the transformer by using insulating oil as a diagnostic medium. During its development, the DGA method has been evolving, among those DGA methods, there is one most recent method that geometrically incorporates five combustible gas that dissolved in oil in order to determine the type of faults. These gases represent the degradation of insulating oil, while the gas that represents degradation of insulating paper is not included in this method. This study offers a way to incorporate CO gas which is an indicator of the degradation of insulation paper into a geometric method that uses six gas combinations instead of five. Determination of the type of faults is done by mapping the identified faults from the IEC TC 10 database into hexagon geometry. It is expected that later the results of this study can be used to determine the type of faults in the transformer both due to degradation of insulating oil and paper.