A Novell Protection Risk Identification Method for Intelligent Substation Based on Greedy Searching

To solve the problem of chain failure caused by the soft platens misoperation of protection in intelligent substation, a novel risk identification method of protection operation in intelligent substation based on greedy searching is proposed in the paper. According to the protection principles, the Petri net models of normal action and abnormal for each protection are established. Then the coupling relation library and coupling state library are constructed to transfer the coupling signals among related protection Petri nets. After setting one equipment failure, the double-layer traversal is studied to enumerate the wrong operation of the soft platens. All related protected Petri nets are traversed and deduced. Finally, the chains of fault events are obtained. Several examples illustrate that the risk identification method can effectively analyze the cascading faults caused by the soft platen misoperations, the extended fault scope can be obtained.