Application Study Of Fault Location For Distribution Network Containing Distributed Generation

With the development of global energy interconnection,distributed generations has developed rapidly because of the advantages of low pollution and low energy consumption.The access of the distributed generations(DG)supply makes the traditional distribution network into a complex multi power supply network which is connected to the power supply and the user,which decreased the accuracy and adaptability of the fault location traditional methods for distribution network.Therefore solution of the problem of fault location for distribution network with distributed power has great significance for improving the reliability of distribution network and promoting the development of distributed generations.According to the current situation of the development and construction of distribution network fault location,this paper analysis the impact of DG access to the traditional methods of fault location in distribution network,by adjusting the value of each switch in the upstream of the DG access point,it can distinguish the minimum forward short-circuit current supplied by the main power supply of the system and the maximum reverse short-circuit current supplied by DG,in order to make the traditional fault location method in DG distribution network still has some applicability;at the same time,the fault location method of overhead line distribution network is analyzed when the DG access capacity is too large and the power supply distance is too long;through the simulation analysis the feasibility and limitations of the switch value adjustment strategy.In view of the limitation of the traditional fault location method when the DG access capacity is too large and DG access capacity is too large and power supply distance is too long,an improved DG algorithm is proposed.According to the flow direction of distribution network,the algorithm defines the positive direction of the switch,the n ?1 fault judgment matrix based on the n ?1 fault information matrix;this paper propose a fault location method to improve the location accuracy of single fault and multiple faults in each region of the feeder when the FTU information is incomplete or distorted;accordingly the algorithm solves the problem that the traditional matrix algorithm needs to make multiple fault location according to the number of power supply,and the fault diagnosis is standardized and the large computation,and the low accuracy of the fault location too T nodes.Lastly,the accuracy and fault tolerance of the improved matrix algorithm are verified by numerical simulation.Due to the actual fault location of distribution network,FTU upload information is easily affected by the external environment,weather and other factors,and when the FTU distortion is more,the fault tolerance of the improved matrix algorithm is greatly reduced,to solve this problem,a genetic algorithm is introduced to fault location of with DG access to distribution network.The traditional genetic algorithm can not adapt to the different switching of DG,which results in the accuracy and stability of fault location,aiming this problem,an improved genetic algorithm is proposed to adapt to the changing distribution network structure.The algorithm improves the convergence speed of the algorithm by improving the crossover and mutation operators and avoids the local optimization;by improving the switching function and fitness function to adapt the DG switching,which improve the stability and efficiency of fault location;in order to solve the problem of large scale distribution network fault location,the idea of hierarchical processing is introduced to accelerate the speed of fault location.Simulation results show the effectiveness of the improved genetic algorithm in fault location of DG distribution network with single fault and multiple faults,at the same time,aiming the problem of the information of FTU upload is distortion and loss,this paper compared the stability,accuracy and fault tolerance of the improved genetic algorithm and the traditional genetic algorithm and the improved matrix algorithm,Numerical examples show that the improved genetic algorithm has better stability and fault tolerance.