Dissolved Gas Analysis methods for distribution transformers

This paper proposes a program development for evaluating a condition of insulating oil of distribution transformer from Dissolved Gas Analysis (DGA) sampling data. The DGA methods such as Key Gas method, Total Dissolved Combustible Gas (TDCG), Dörnenburg Ratio method, Rogers Ratio method and Duval Triangle method are applied to assess actual condition of distribution transformer. All five methods are developed by excel program for simple usage with minimum cost of utility. A total of 50 distribution transformers in Thailand are analyzed and compared to identify actual conditions of those transformers. However, two transformers show evaluation method and procedure. Finally, the total dissolved combustible gas (TDCG) method is applied to recommend the maintenance tasks to the transformers.