Research On Fault Location Of Distribution Network With Distributed Generation

The grid connection of a large number of distributed power makes the traditional distribution system constantly changing,which also brings various problems to the fault location and ranging of the distribution network.This topic will focus on the impact of the inverter distributed power including photovoltaic,wind and other clean energy generation on the fault location of the main network.First of all,the control characteristics of the distributed power generation are analyzed,and its grid connection characteristics are studied;when the short-circuit fault occurs in the grid connection state,the influence of the incorporation of the distributed power generation on the changes of electrical parameters such as the voltage and current of the main network is studied,and then the interference source caused by the incorporation of the distributed power generation on the fault location is clarified.Then,based on the zero sequence current,EEMD algorithm and wavelet analysis are used to decompose the zero sequence current signal and establish the simulation model;the difference calculation is carried out to get the corresponding difference component,and the fault line is obtained by comparing the maximum value of diff3 component.It is found that the EEMD method is not interfered by fault location,transition resistance and other factors,and the accuracy of line selection is high.Secondly,the research of active distribution network fault location scheme is established,the fault characteristics of active distribution network are analyzed briefly,and the difference of distribution network fault circuit before and after the access of distributed power is analyzed.Then,based on the real-time location,the active distribution network region partition scheme based on active / passive tree is proposed to reduce the solution space,and the improved particle swarm optimization algorithm based on bacterial chemotaxis is analyzed.The application of location;then build a fault location model and simulation to adapt to the switching of distributed power supply,and realize the accurate location of fault section in the single fault / multiple faults,no distortion / distortion of fault information,switching of distributed power supply and other situations of the distribution network of inverter distributed power supply including photovoltaic,wind power and other clean energy generation.Finally,on the basis of fault line selection and fault section location,the active distribution network fault location based on 4-layer wavelet decomposition transform is studied.This paper analyzes the characteristics of traveling wave after single-phase ground fault in active distribution network,and then uses DB2 wavelet to decompose the traveling wave of fault current in four layers,and then calculates the fault distance according to the time interval of modulus extremum after decomposition and the transmission speed of traveling wave.Simulation results show that the proposed scheme can achieve accurate fault location in active distribution network.