Transformer failure gas monitoring system and method

The invention relates to transformer failure gas monitoring system and method. The transformer failure gas monitoring system adopts an oil-gas separating device (100) and comprises an optical fiber gas sensor (200) of a distributed feedback type laser (206), wherein the oil-gas separating device (100) separates a failure gas in a transformer to a gas chamber (104); the output light of the distributed feedback type laser (206) in the optical fiber gas sensor (200) is transmitted to an optical fiber gas sensing head (201) of the gas chamber (104) and transmitted to an optical detector (202) to carry out photoelectric conversion; and then the output light is transmitted to a bandpass filter (203) to be filtered and amplified and input into a FPGA (204) and an industrial personal computer (208) to carry out analysis so as to perform judgment on the condition of the transformer. The system and the method enable a plurality of different gas sensing heads to share a same set of light source and detecting system and realize the simultaneous measurement of low cost, multipoint and a plurality of gases.