Study And Application On Power Grid Fault Diagnosis System

Now, fault information system (power system relay protection and fault information process system) is building in most provinces' electric power system. When there is fault in 220kV power system, fault information is transferred to dispatching certre through network. Dispatcher can judge which device result in the fault and the type of fault using the information of fault information system in time, and then change the run mode of power system to protect system's security.Fault diagnosis system is the subsystem of the fault information system. Its funtion is to disgnosis the fault device with the information of the fault information. According to the current operating situations of power systems and its evolution in the future, this paper presents a new approach to carry out hierarchical fault diagnosis by using the collected messages. There is only the information of protection devices and recording oscillographs in the fault information management system at the stage one. Fault can be diagnosed on basis of deducing algorithm of protective relays. Once linked to SCADA system, fault information management system can collect the information of circuit breakers, protection devices and recording oscillographs. Then the fault can be diagnosed based on genetic algorithm. When the fault happened in power system, fault information was transferred from stations to dispatcher department include the information of protection devices and recording wave devices collected by fault information management system and the information of breakers collected by SCADA system. Fault diagnose system is triggered when fault information is received. Firstly possible fault area is ascertained, and power network topology is built. Then diagnose the fault equipment using deducing algorithm. Finally, analyses the behavior of breakers and relays. Furthermore, this paper modifies the goal function which is used in previous optimal algorithm by add direction component and high frequency component so that the result is more accurate. After studying the further diagnosis of complex faults by using the recorded fault messages in order to remedy limitation of diagnosis using breaker and relay alarm messages. Compared to other fault diagnosis system this paper presents new method of two stages diagnoses which is more significative in realistic application. Then evaluate the behavior of breakers and relays using expert system which make the fault diagnosis system more perfect. At last, this paper discusses some new types of fault diagnosis system and brings new ideas for improving this system.