By using Practical Reading to Perform Incipient Fault Diagnosis of Transformer Oil using Dissolve Gas Analysis Based on Fuzzy Three Gas Ratio Method

The most common internal fault diagnosis method of power transformer is Dissolved Gas Analysis (DGA) [1-4]. It is a sensitive and reliable technique for the detection of incipient fault condition within oil-immersed transformers. There are a number of methods developed for analyzing these gases and interpreting their significance. These methods are, Roger gas ratio, IEC gas ratio and Duval Triangle[3]. Here we used fuzzy three ratio method to resolve the fault diagnosis problems for oil-filled power transformer. In fuzzy three-ratio method; we considered that the drawbacks of the conventional three-ratio methodlie in: when The ratio crosses the coding boundary, codes changes harply, but in reality the boundary should befuzzied. Based on this assumption, this paper first propose the fuzzy membership functions for codes"0","1","2", then it transfer the conventional logic "AND" and "OR" used in IEC three-ratio method into fuzzy logic and put forward the diagnosing steps of this method. Simulation proves the proposed method can overcome the drawbacks of the conventional three-ratio method can't diagnose multi-fault and no matching codes for diagnosis, thus, it greatly enhanced diagnosing accuracy. In the aspects of experimental work done I have taken data from oil testing lab vidyut bhavan Nagpur.