Research On Voltage Sag Source Location In Power System Based On Monitoring Bus Optimization

With the innovation and development of science and technology,a large number of sensitive and precise equipment have been put into people’s production and application,which has stricter requirements for power quality.As the most prominent problem in power quality,voltage sag occurs frequently and is random,which seriously affects the normal operation of various equipment in the system.Accurate location of voltage sag is a prerequisite for efficient management of power grid faults,and is of great significance for improving power supply reliability and clarifying supply and demand responsibilities.For the precise location of the voltage sag source,the traditional location method is only suitable for a simple transmission network or needs to traverse all the bus bars,which requires a lot of computation and cannot achieve precise location.For a complex power network,the positioning accuracy is related to the configuration of monitoring points.However,considering economic factors,monitoring devices cannot be installed at all nodes.Therefore,a reasonable optimal configuration of monitoring points is the premise of accurate positioning.In order to obtain data accurately and efficiently to evaluate the fault,this paper assumes that the voltage sag can be observed in the whole network,and on the basis of optimizing the monitoring point configuration,according to the monitoring data and system parameter information,the rapid and accurate positioning of the voltage sag source is completed..In order to simplify the voltage sag positioning process and improve the applicability and accuracy of the positioning method.This paper starts with the analytical calculation of voltage sag,and constructs an observable matrix by the segmentation method to optimize the monitoring configuration scheme.However,when analyzing and calculating the characteristic phasor of voltage sag,due to factors such as weather and environmental changes,the fault resistance is random,which leads to the problem of blind spots between monitoring points.In order to reduce the influence of fault resistance,and taking into account the factors of economy and data redundancy,this paper uses the observation ability improvement segmentation method to construct an observable matrix.The redundancy is the objective function,and the non-dominated sorting genetic algorithm(NSGA2)is used to realize the multi-objective optimization of the voltage sag monitoring points.After the monitoring point configuration plan is determined,according to the information collected by the monitoring points,the upstream and downstream positioning method is used to establish the set of possible fault lines in the area where the sag source is located,and the similarity index is constructed by combining the Pearson correlation coefficient method and the Euclidean distance method.The fault line is screened out from the set by the similarity information matching method,and the specific location of the fault is solved by using the particle swarm optimization algorithm.It realizes the hierarchical positioning from the fault area to the fault line and then to the fault point in the complex power distribution network.The research results are tested in the IEEE30 bus simulation system,and the optimal layout scheme of monitoring points and the hierarchical positioning strategy of sag sources are verified.By analyzing the location,quantity and redundancy distribution of monitoring points and the accuracy of sag source location,the results prove the effectiveness and feasibility of the method in this paper.