The Research On The Topology Identification Method In Low Voltage Distribution Networks

The low-voltage distribution network is located at the end of the power grid,which is an important link between the power grid and power use rs.However,in the process of urban and rural power grid transformation,there are problems such as missing and misreporting topology information in the GIS system data of the low-voltage distribution network,which seriously affect the refined management of the distribution network.In order to improve the management of low-voltage distribution network,it is necessary to identify the topology of low-voltage distribution network,and obtain the accurate user-transformer relationship and phase connection relationship of station area users.Aiming at the problems of topology ledger error and low accuracy of topology identification in low-voltage distribution area,two methods are proposed to identify the topology of low-voltage distribution areas and the superiority of the identification methods is verified by means of calculation examples.Firstly,the characteristics of low-voltage distribution network and its automat ion are introduced,and the topology of low-voltage distribution station and the physical architecture of data collection are described;then the power flow calculation method of low-voltage distribution station based on the forward-backward sweep method is introduced;then the simulation model of low-voltage distribution network topology is established;finally,the characteristics of power data and the basic principle of low-voltage distribution station topology identification are discussed.In view of the problem that there are errors in the recorded data of the topology of the low-voltage distribution network,a topology identification method based on dynamic time warping distance and cluster analysis is proposed.The DTW distance between voltage sequences is used to measure the similarity between user voltage curves;the clustering analysis of user voltage curves is performed based on the principle of minimum-maximum distance to identify the station areas to which low-voltage users belong,and the phase identification of users within the same station area.The method is capable of analyzing unequal voltage time series,insensitive to missing or abnormal voltage data,and does not require artific ially set thresholds,with high accuracy of topology identification.The simulation results of the algorithm verify the correctness of the proposed method.Aiming at the problem that the user-transformer relationship and user phase identification are prone to errors when the voltage profiles of users in different st ation areas are similar,a method of identifying the topology of low-voltage distribution station areas based on the characteristic parameters and regression analysis is proposed.The method establishes an evaluation model based on the similarity of voltage sequences of characteristic parameters,and the regression analysis of voltage deviation and the similarity of characteristic parameters is used to obtain the station area and phase to which users belong.The results of the algorithm show that the method can identify the correct station area and phase for the users.