Review on Incipient Fault Diagnosis for Power Transformer using Dissolved Gas Analysis Based on Fuzzy Three Gas Ratio Method

Dissolved Gas Analysis is useful method to detect incipient faults in transformer [1-4] .three ratio method is widely used for detection of incipient fault. When more than one fault exists in a transformer, these methods sometimes fail to diagnose. IEC Three Ratio Method is widely used, but in many cases this method can not accurately diagnose. Fuzzy Three Ratio Method; overcome the drawbacks of Conventional Three Ratio Method .its drawback is when the ratio crosses the coding boundary, codes change sharply, but in reality the boundary should be fuzzied. This paper first propose the fuzzy membership functions for codes "zero", "one", "two", 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.