Abstract: Aiming at the phenomenon of pressure relief and deflagration caused by the faults of oil-immersed

transformer，a logic was proposed that the transformer can keep self-maintained running when faults occurred，and according to the logic，a scheme of oil circuit equipment was designed. The above logic and the scheme together constructed a method of self-maintaining operation of oil-immersed transformer. The application of the method could reduce the power outage time caused by transformer failure to achieve the purpose of timely restoration of power supply. At the same time，it alleviated the influence on the surrounding personal and property safety and environment when the transformer produces pressure relief or deignition accident. The method provides a new idea for the designers of intelligent transformer.

      Key words: oil-immersed transformer；self-maintained running；logic；oil circuit；pressure relief of failure