Power System Fault Layered Abductivive Analysis Based On Directed Graph And Fault Tree

With the increasing complexity of the power network configuration, when the faults occur in the grid, a large number of fault information are sent to the dispatching center and the substation will be filled with a lot of alarm information,the dispatchers face considerable difficulties to handle them promptly and effectively.In this paper, combining protection and circuit breakers information in dispatch center with substation level alarm information, analyze the reason of protection and circuit breaker of incorrect action.The basic principle of the fault tree and directed graph are described first in this paper, and then the application of directed graph in the aerospace industry and fault tree diagnosis method in fault diagnosis of grid are stated. Both of the methods have good theoretical basis and practical value. This paper attempts to bring the fault tree method and directed graph into the grid fault diagnosis abductive analysis.This paper studies the method of grid fault diagnosis based on the fault tree diagram and directed graph. Firstly, the model of directed graph of interactions within the substation IED is constructed, it can clearly describe logical relation between components with the relevant protection,protection and circuit breaker, according to this correct operation and misoperation event chains of protection and circuit breaker are established.The actually collected reporting and alarm informations of protection and circuit breaker are matched with the constructed event chains.Finding the best matching event chains and analyzing reason of protection and circuit breaker incorrect action,tracing the execution process of instructions.This paper studies the method of constructing abductive fault tree based on intelligent substation alarms. The dispatching information and substation information are combined to construct the protection and breaker incorrect action fault tree. When faults occur in power grid, based on the protection and breaker action information in dispatch center, with the existing Bayesian diagnostic method, it can diagnoses the fault elements and the incorrect action of protection and breakers. Collecting alarm information and reporting information of incorrect action of protection and circuit breaker in the substation layer during a period of time.The collected information is assigned to the corresponding fault tree leaf node, and matching with corresponding fault tree model of minimal cut sets. Obtaining the best matching minimal cut set calculating the probability of top event and giving the path leading to top event occurred and analyzing reason.This paper studies the method of layered abduction based on directed graph and fault tree. Through multiple examples to verify the accuracy and validity of the method. This method can display the process of information interaction intuitively and mutual influence relationships between protection in substations.