Research On Single-phase Grounding Fault Line Selection Method Of Distribution Network Based On Wavelet Analysis And DTW

When a single-phase ground fault occurs in the distribution network,it is of great significance to quickly select the fault branch and restore national production.Due to the extremely complex operation of the distribution network,the fault line selection accuracy is poor and the reliability is low.Therefore,this paper studies the transient characteristics of zero-mode current,constructs a single-phase ground fault line selection method for distribution networks,and realizes accurate identification of fault branches.Construct the equivalent model of the single-phase grounding mode network of the distribution network.The analysis of the distribution network mode network shows that the transient zero-mode current waveform between the fault branch and the non-fault branch is quite different,and the transient zero-mode current waveform between the non-fault branch and the non-fault branch The shape is similar.This fault characteristic is used as the theoretical basis for fault line selection of distribution network faults.Proposes the method of fault line selection for single-phase grounding of distribution network based on wavelet analysis and dynamic time bending distance.First,select the wavelet analysis with time-frequency characteristics to perform wavelet decomposition on the zero-mode current,and use the wavelet coefficients of the zero-mode current corresponding to the 1/4 cycle after decomposition to form the wavelet coefficient matrix;,Get the zero-mode current wavelet coefficient dynamic time bending distance matrix of the fault branch and non-fault branch;finally,identify the similarity of the distance matrix of the fault branch and non-fault branch,obtain the fault line selection vector,and After the elements in the line selection vector are normalized,the element with 1 is the fault branch.In order to verify the accuracy of the single-phase ground fault line selection method based on wavelet analysis and dynamic time bending distance proposed in this paper,the distribution network simulation model is established in Matlab/Simulink software to carry out the fault line selection method in this paper The simulation verifies that the single-phase ground fault is simulated under different grounding conditions,and the data is processed through the Matlab.The simulation results show that the simulations under different grounding resistances,different initial phase angles of different faults,different distances of faults and different system compensation methods verify the correctness and effectiveness of the fault line selection method based on wavelet analysis and dynamic time bending distance.In order to further verify the effectiveness of the line selection scheme proposed in this paper,a physical model of the 10kV distribution network was constructed for a large number of experimental verifications under different fault conditions.The results show that the fault line selection method is accurate,reliable,effective and adaptable.