Research On Lightning Overvoltage Transient Characteristics Of Overhead Transmission Lines

With the continuous development of China’s industrial economy, the ultra-highvoltage power grid is also unceasingly enhanced. In particular, the height andtransmission distance of the EHV transmission line is improving. Because ourcountry is a large country and has a complex and diverse topography, the highvoltage overhead transmission lines are enduring all kinds of test in the wilderness.Lightning failures happen from time to time poses a threat to the operation of theultra-high voltage power grid in our country. In recent years, as with the doublecircuit transmission line towers are widely used, its design, manufacture, constructionand operation has been very mature, however, grid accidents caused by lightningcontinue to occur. In order to formulate more effective lightning protection measures,reduce lightning accident; we need a more accurate analysis of the lightningovervoltage transient characteristics. Through simulation, we can explore itsregularity to provide valuable reference for lightning protection design of new lines,it also has far-reaching significance and practical value in engineering to improve thelevel of the existing transmission line lightning protection.The paper analyzes the transient characteristics of500kV EHV AC transmissionlines according to the occurrence mechanism of lightning overvoltage by using theelectromagnetic transient simulation program PSCAD/EMTDC. Transmission linelightning simulation model including the lightning current model, transmission linemodel, the tower model, insulator flashover model and arrester model. The paperanalyzes the factors affecting lightning overvoltage based on PSCAD/EMTDCsimulation model And analyzed the effect of line arrester, unbalanced insulation andcoupling wires to improve the lightning resisting level of transmission line.According to the500kV EHV transmission lines actual working condition, the paperhas carried on a statistical analysis with the lightning tripping accidents data in recentyears. And for a specific counter and detour lightning fault simulation, effectivelightning protection strategy is put forward. In this paper, the research achievementsof the study of500kV EHV transmission line lightning over-voltage provides avaluable reference.