Research On Fault Line Selection And Section Location Method Of Distribution Networ

In order to meet the reliability of power supply,China’s distribution network generally adopts the small current grounding operation mode.When a single-phase ground fault occurs in the system,long-time operation with fault can easily lead to the development of single-phase faults into two-phase or three-phase faults,and cause serious consequences such as damage to the weak links in the system or even the expansion of the blackout range.Therefore,it is important to identify the fault line and determine the fault location quickly and accurately to improve the reliability of power supply in the power system and the development of social economy.For the influence of different fault conditions and distributed generation(DG)input on the fault line selection effect,the method of line selection is based on the transient zero sequence current and uses support vector machine(SVM)as the base model;to improve the line selection accuracy,the SVM is optimized by whale optimization algorithm(WOA).To improve the line selection efficiency,the data are pre-processed by principal component analysis(PCA),and the PCA-WOA-SVM fault line selection model is finally formed.By simulating and analyzing the SVM,WOA-SVM,PCA-SVM model and the PCA-WOA-SVM model in this paper under different fault conditions,the results show that the fault routing model in this paper has higher routing accuracy and routing efficiency.By comparing the WOA used in this paper to optimize the SVM with different algorithms under different fault conditions,the results show that the WOA algorithm can obtain a better performance of the SVM routing model.In addition,simulation experiments are also conducted for systems containing DG at different DG access locations.The results show that the fault routing method in this paper can adapt to the DG dropout and is not affected by the DG access location,which has high applicability.In view of the difficulties in locating fault zones in distribution networks after DG is put into operation,as well as the problems of complex single-level zone location model and slow location speed,the fault zone location idea based on hierarchical partitioning is used for the first-level zone location by matrix algorithm and the second-level zone location by binary bat algorithm(BBA).The method makes full use of the advantages of simple and fast positioning of matrix algorithm,and combines the idea of hierarchical positioning to further reduce the solution dimension of overall positioning.At the same time,the accuracy of overall localization is improved by optimizing the consistency of the algorithm with the localization results of the two layers.Finally,simulation experiments are conducted considering different fault weights,information distortion,DG cast-cut combinations,and positioning models.The results show that the method in this paper has high localization efficiency and fault tolerance,and can achieve fast area localization and accurate zone localization.In addition,the performance of the algorithm BBA used in this paper for zone positioning is compared with the binary particle swarm optimization algorithm(BPSO)and binary sparrow search algorithm(BSSA),and the experimental results show that the BBA algorithm shows a better performance in terms of positioning efficiency and positioning accuracy.