Research On Fault Location Technology Of Multi-branch Distribution Network Based On Micro PMU

Distribution network is a key part of the power system which faces users directly.Its safe and stable operation is closely related to power quality,supply efficiency and safety.However,distribution network is a frequent part of short-circuit faults in the whole power system,so it is important to research the fast and accurate fault location technology for distribution network.Although many methods for fault location in distribution networks have been proposed,most of them are difficult to solve the problem of fault location in multi-branch distribution networks.With the gradual improvement of distribution network intellectualization and initiation,and the rapid development of Phasor Measurement Units,the advantages of PMU such as high sampling frequency,accurate clock synchronization and phase measurement provide new ideas for the development of fault location technology.The micro PMU developed for distribution network can not only reduce equipment costs,but also ensure high accuracy,high sampling rate and clock synchronization,making it possible to install on a large scale in distribution network,and making it possible for distribution network.The development of fault location technology provides better data base.Based on this,this paper mainly carries out the following research.First,the generation mechanism of fault traveling wave in power system and the basic principle of its propagation along the line are researched and analyzed.Based on the wave process and refraction law of fault traveling wave transmission along the line,two traditional traveling wave ranging principles,type A and type D,are analyzed in depth.This paper summarizes the advantages and disadvantages of these two traditional traveling wave ranging principles,discusses their applicability in distribution network fault location,and puts forward a feasible idea for distribution network fault location technology by using their mutual cooperation and complementary advantages.Then,in view of the characteristics of large-scale network,numerous branches and complex structure of distribution network,the basic theory of distribution network zoning is researched,and the topological ordering method and the propagation law of multi-branch distribution network fault traveling wave are simulated and analyzed.This paper presents a method to simplify the complex topology of distribution network by dividing the multi-branch distribution network into regions to form a characteristic network,and to reduce the difficulties of traveling wave method in the application of multi-branch distribution network.The propagation rule of fault traveling wave in the characteristic network is further researched.The principle of multi-branch distribution network partition and the principle of micro PMU configuration in the characteristic network are proposed in combination with the basic theory of distribution network partition.The distribution network model with IEEE 14 node standard topology is used to simulate and validate.Finally,based on the characteristic network partition and micro PMU configuration of multi-branch distribution network,the polarity of fault traveling wave in the case of branch failure in the feature network is analyzed,and a branch fault traveling wave identification algorithm for the feature network is presented.Based on the idea of locating the fault section first,then accurately measuring the fault point,a traveling wave fault location algorithm based on micro PMU is presented by using the combination of single-end traveling wave method and double-end traveling wave method.MATLAB/Simulink simulation software is uesd to build a multi-branch distribution network model based on IEEE 14 node standard topology to simulate and analyze the proposed branch fault traveling wave identification algorithm and multi-branch distribution network fault location algorithm.Different fault locations,fault types and transition resistors are set up in the simulation to verify the effectiveness,accuracy and applicability of the algorithm proposed in this paper.The simulation results show that the proposed fault traveling wave identification algorithm has good stability,and the proposed fault location algorithm can accurately and reliably achieve the task of fault location.