Fault Diagnosis Method Of Distribution Network Based On Multi-source Information Fusion

Due to the large number of equipment in the distribution network and the complicated connections,the correct determination and treatment of the faults in the distribution network will have a great impact on the stability of the power supply.After the fault occurs in the distribution network,the dispatch center will receive a large number of warning signals in a short time,which will adversely affect the dispatcher’s timely determination of the fault location and correct handling measures.Therefore,it is necessary to build a fault diagnosis system for distribution network that can deal with the fault warning signals quickly and determine the fault location accurately.In addition,the protection and switch may have misoperation or rejection,and the alarm signal may have false alarm or omission,which makes it more difficult for the dispatcher to diagnose the distribution network fault.Through the comprehensive utilization of analog information and GIS technology when the fault occurs in the distribution network,and the full consideration of the possible occurrence of misoperation or rejection of protection or switch,as well as false alarm or omission of alarm signals,this paper develops analytical model and method based on the traditional distribution network fault diagnosis analytical model,which can diagnose the distribution network fault well.The main results of the thesis are as follows:Firstly,based on the traditional distribution network fault diagnosis analytical model,this paper proposes a new method of distribution network fault diagnosis based on digital information by combining the action characteristics of the distribution network protection system The analytical model of distribution network fault diagnosis is based on the relationship between protection and switch action signals to construct the objective function of the difference between the actual alarm signal and the expected state,thereby expressing the problem of distribution network fault diagnosis as a 0-1 mathematical optimization problem of objective function minimization.The analytical model of distribution network fault diagnosis based on alarm signals and fault hypothesis can realize the diagnosis of fault component.At the same time,through a simple distribution network calculation example,the logic relationship of protection and switch operation is analyzed,the expected state formula of protection and switch is obtained,and the validity of the distribution network fault diagnosis analytical model is verified.Secondly,in order to further improve the information redundancy of the analytical model,this paper develops an analytical model of distribution network fault diagnosis that integrates the analog information.Through the analysis of the bus current in the distribution network with distributed generator,a fault diagnosis method of distribution network with distributed generator based on Fortescue is proposed.In order to improve the redundancy of the analytical model to the system fault,a new objective function is constructed by integrating the model criterion established by the phase selection function of the distribution network realized by the analog information.Through the analysis of calculation examples,this method is proved to be able to accurately diagnose faults when the protection and switch of the distribution network are misoperated or rejected and the alarm signal is misreported or missed.Subsequently,an analytical model of fault diagnosis based on integrated distribution network geographic information is proposed.Through the application of GIS technology,the hierarchical topology of the distribution network and the location information and operating status of each component are stored as spatial data and attribute data.The topology of the distribution network can be divided into three levels,namely point equipment,line equipment and surface equipment.Various types of equipment are stored in GIS spatial data through formula coding,thus establishing a GIS distribution network map.According to the switch status information collected by the SCADA system,the fault determination matrix is determined,which determines the fault equipment,protection and switch sets contained in the fault area combined with the GIS distribution network.In the fault hypothesis,it is necessary to fully consider the misoperation or rejection of the protection and switch and the false alarm or omission of the alarm signal,so as to determine the expected state of the protection and switch.Through the analysis of calculation examples,the analytical model of distribution network fault diagnosis integrated with GIS is verified to be able to realize the fault diagnosis and location of distribution network fault in a fast and accurate way,and can visually display the geographic location information of fault components,thus realizing the purpose of improving the efficiency of fault diagnosis and power supply quality.