A fault state evaluation method for relay protection equipment

The healthy operation of China’s new electric power system is highly dependent on the relay protection equipment as the first line of defense, and the self-checking alarm of the relay protection equipment is the key to discover equipment fault. Aiming at the problem that the current fault state of the equipment is difficult to be effectively determined based on the self-checking alarm information of the equipment, this paper proposes two characteristic indicators, which are the frequency and deterioration degree of self-checking alarm. On this basis, this paper extracts samples from relevant historical cases, adopts the piecewise linear classification and fitting curve of Sigmoid function, constructs a fault state evaluation function with characteristic indicators as input and fault state in probability form as output, realizing effective analysis of fault state. Practical cases verify the effectiveness of the proposed method.