Research On Signal Generation And Identification Of The Distribution Network Ground Fault Location System

The distribution network because of its complex structure,branch lines,characteristics such as wide coverage,thus the high failure rate.And in fault in power distribution network,single-phase earth fault accounts for a large part of.But the single-phase earth fault fault current value is very small,not easy to detect the apparent breakdown electric parameters,so there is no perfect method for detection and positioning.Relevant researchers in recent years for single-phase earth fault of distribution network is carried on the thorough research,and achieved some results.But the power of single-phase grounding fault location problem has not been fully effective solution.This paper presents an active signal injection method based on power electronic technology to locate the single-phase earth fault,when single-phase earth fault,after the formation of the injection has obvious characteristics in the fault loop controlled current disturbance,the disturbance signal detection device on the line by identifying the characteristics of the signal to determine the fault,so as to realize fault location.Before this method than the traditional method is flexible,and high safety,grounding resistance for 1000 ? fault can be detected.For single-phase earth fault of distribution network based on power electronic technology of the active signal positioning methods,this article main research content is as follows:(1)To solve the problem of injection of traditional signal method with the time is long,characteristic is not obvious,the signal strength affected by grounding resistance defects such as large,in this paper,using the power electronic devices of the thyristor conduction Angle precisely control the size and length of disturbance signal.(2)Analyzed the state of circuit failure occurs,and determine the fault phase brake pipe judgment method of the conduction phase.Through the establishment of simulation model of fault location method has been verified the rationality and effectiveness,and the main parameters of new type of disturbance signal generator is used for calculation.(3)To disturbance signal generator to produce electricity in order to be able to accurately extract,using "double extraction algorithm was proposed to extract the disturbance signal,and USES the energy method and spectrum method to criterion ofpower disturbance signal.Finally simulation model and dynamic model experiment system is designed to certify its methods,results show the rationality and effectiveness of the method.(4)Design test verifies the disturbance signal generator prototype and disturbance signal detection device prototype,through the analysis of test data,the active signal positioning method has been proved effective good use effect.