Research On Lightning Overvoltage And Flashover Distribution Characteristics Of Overhead Lines

In recent years,with the insular transformation of urban overhead power distributionnetworks and the expansion of the area covered by overhead lines in rural areas,frequent accidents due to lightning strikes have severely affected the reliability of power supply.The problem of lightning line breakage on overhead lines has existed for a long time.Over the years,due to the small scope of impact of distribution network accidents,this issue has not been given sufficient attention.However,with the continuous increase of electricity consumption and the continuous expansion of overhead lines,the problem of lightning strikes on overhead lines of distribution networks have attracted the attention of the power sector.In particular,the distribution of overhead lines in distribution networks is large,and it is not possible to install lightning protection devices on the entire line.Protection is weak.The number of disconnections per year in the country is as many as a thousand times,and the number of times not in the statistical range cannot be underestimated.According to the lightning company’s lightning accident statistics,10 k V overhead insulated lines and bare conductors that have been operating for many years have the problem of lightning strikes.According to actual investigations in recent years,dozens of 10 k V overhead lines in a certain area of Liaoning province have experienced lightning strikes every year.In 2014,there were more than 20 accidents of lightning strikes on 10 lines.The accident of lightning strikes on overhead lines has increased the burden on the operation and management of the power sector,and has also caused huge economic losses for the majority of power users.It must be given high priority and effective solutions.This paper mainly focuses on the research and analysis of the lightning-breakage of 10 k V overhead lines.Firstly,by conducting field investigations on the lightning strikes in a certain area and combining the analysis of the level of lightning resistance in the area,the generality of the lightning strikes in the area was obtained.The lightning overvoltage model was established to study the mechanism and experimental study of lightning strikes.Provide the necessary practical basis.Secondly,based on the structural parameters of overhead lines,ATP-EMTP simulation software is used to establish the lightning-induced overvoltage model of distribution network.The changes in the voltage across the insulator during the lightning are analyzed,and thesimulation data under certain line parameters are obtained.Compare the effects of various lightning protection measures on limiting lightning overvoltage.Finally,through comprehensive analysis of the electric power,thermal buoyancy and aerodynamic forces experienced by the arc of the flashover process,the development and evolution characteristics of the arc are briefly analyzed.And build a lightning breakage test research platform,through the high-speed CMOS camera to obtain the distribution characteristics of lightning flashover near the overhead line insulators,to provide a basis for solving the problem of lightning stroke broken line and lightning protection design of the power grid.