Power system fault diagnosis with a weighted fuzzy time Petri net

The existing researches for power system fault diagnosis based on Petri net have not taken into account the time-delay constraints of the components, and the malfunctions of protective relays and breakers. Given this background, a power system diagnosis model based on weighted fuzzy time Petri nets (PNs) with taking the time-delay constraints into account is proposed. First of all, the interrupted districts can be figured out by the power network topology and the alarm message of the protective relays and breakers offered by the SCADA system. Then weighted fuzzy time PN (WFTPN) for the possible fault components in the interrupted districts, which can adapt to topology changes, is constructed to confirm the fault components with considering the time-delay constraints of the components and the malfunctions of protective relays and breakers. At the same time, the reasoning process based on a mathematical matrix algorithm is given to analyze the method, which can improve the practicability and veracity of the model. The integrality and the exactness of the alarm message can be diagnosed to identify the malfunctioning protective relays and breakers by using the backward reasoning. Finally, the IEEE 39-bus power system is used to demonstrate the diagnosis model based on the weighted fuzzy time PN proposed. The validity of the method has been proved by the simulation result.