Abstract: Transformer insulation aging diagnosis is important for all the condition assessment Dissolved gas analysis (DGA) is one of the most useful techniques and tools to detect the incipient faults in large oil filled transformers. DGA is most useful condition monitoring technique as primary diagnosis method for detecting incipient fault in oil filled transformer in this paper I have use MATLAB programing to detecting present transformer condition according to Dissolved gases in transformer oil as per IEC and IEEE Gas ratio code. It also describes the structure and specific features of transformer insulation ageing diagnosis based IEC codes and Rogersís ratio method. MATLAB programs using this two methods were developed to automate. Also this paper present three fault type, partial discharges (PD), arc discharges, and thermal faults, Winding circulate current.

Keywords: Acetylene (C2H2) , carbon monoxide (CO), carbon dioxide (CO2), Dissolved gas analysis (DGA), ethylene (C2H4), ethane (C2H6) ,Key gases, hydrogen (H2), methane (CH4),.