Research On Fault Diagnosis Method Of Power System Based On Petri Net

With the continuous development of the economic society,people's demands for power quality and supply reliability have gradually increased.Power system,as an indispensable link between power plants and users,its operation state is directly related to the reliability of the entire system and the quality of the power supply to users.In order to reduce the impact of faults in power system,it is necessary to make full use of the fault information for fault diagnosis quickly and accurately.Petri net,as a method of behavior analysis and mathematical expression of discrete events,has been widely used in power system fault diagnosis because of its powerful knowledge representation and logical reasoning functions.Therefore,it is of great practical significance to study the fault diagnosis method based on Petri net.In order to reduce the complexity of the model for transmission network fault diagnosis and enhance the flexibility and versatility,the power system fault diagnosis method based on the weighted fuzzy Petri net considering time association character is proposed in this thesis,where temporal information of alerting signals is used fully,on the basis of WFPN.And the method of time association character checking and fault diagnosis reasoning process are given.The results of case verification and comparison with different diagnosis methods show that the diagnosis results can be obtained accurately under the complicated conditions such as information absence,maloperation and misstrip,time error of protection and circuit breaker.Secondly,this thesis expands Petri nets to fault diagnosis in distribution network.A fault diagnosis method based on fault power criterion and Petri net with inhibitor arc is proposed on the basis of operation characteristics and topological structure of distribution network with DG.Then the case analysis shows that the method is accurate and effective.Finally,a set of fault diagnosis system for power system based on WFPN is designed by using LabVIEW graphical editorial language to assist the operating personnel to maintenance better and faster.