Abstract: It is very important at home and abroad to detect the internal fault of oil filled electrical equipment by analyzing the dissolved gas in insulating oil with gas chromatography. The analysis technology of dissolved gas in transformer oil is used to judge the transformer failure according to the components and content of the gas in transformer oil, the fault type, general fault location, fault severity and fault development trend of the transformer are further analyzed, and some targeted preventive measures are accordingly put forward, so as to realize online detection and fault diagnosis and reduce the probability of transformer failure. It provides guidance for safe operation.

Key words: transformer oil, dissolved gas, online detection, fault diagnosis