Research And Design Of The Lightning Shielding Of Hunan Province’s Transmission Line

With the increase of transmission power ,voltage level,transmision line lenth of power grid, a variety of power failure problems will emerge,the problems caused by thunder-lightning among them can not be ignored.What should we do to protect the power grid become more important at present. The design of lightning shielding of transmission line is a long-term, important and arduous task,this paper done in-depth research surrounding it.It expounded the basic principle of thunder-lightning discharge and the damage to the power grid transmission line caused by thunder-lightning discharge.It briefly introduced the thunder-lightning theory ,such as the formation and development of thunder-lightning,the formation of thunder-lightning voltage and current,the principle of thunder-lightning breakdowned porcelain insulator,the parameters of the thunder-lightning.It also discussed the related calculation of the thunder-lightning protection design of power grid transmission line,included the calculation of the withstand voltage, induced overvoltage, direct lightning stroke over-voltage, lightning trip rate of transmission line.It deeply researched the running situation of the Hunan power grid and analysed the related running data in deep ,then reasoned out the possible causes and main causes of lightning line trip.Combining with the analysis result of Hunan power grid, it gived the corresponding methods and proposes of lightning shielding design of transmission line. Based on common approach of lightning shieding design, this paper also described the lightning shieding design of the 220kV Zhulu line in detail,this design combined with the local practical situation,such as terrains,weather,environment, the power network operating conditions . The lightning shieding work which after erecting the transmission line also were given in the design.