Application of expert system based on mixing reasoning in traction substation fault diagnosis

When there is a fault in traction substation the fault components and their reasons are required to be identified by operators quickly and accurately. A fault diagnosis expert system based on mixing reasoning is built in this paper. It can reason according to logical relations of relay protection and breakers and fault waveform of voltage and current provided by Fault Record System (FRS). Mistrip and failure to trip of relay protection and breakers can both be distinguished The reasoning result has a good credibility. Traction substation fault diagnosis expert system may be used as a module of integrated automation.