The Research On Switching Overvoltage In 1000kV Transmission Lines

With the voltage class upgrading of the electric network,the allowable value of switching overvoltage of the transmission lines are more and more concerned. Dielectric level is an important technical and economic parameters in UHV transmission, moreover multiple of overvoltage have the direct relation with dielectric level. Capacitance reaction of nonleaded line will cause severity overvoltage, on this condition switching will cause overvoltage much more in the UHV transmission lines and its equipments. How to limit switching overvoltage is the first problem for solving in UHV developing. Arrester and closing resistor, which are extensive used to limit switching overvoltage in EHV home and abroad, is not good enough for the UHV.Firstly, the necessary of establishing UHV network is originated from the practical situation of energy distribution and economic development in our country, its research and development home and abroad are depicted, various switching overvoltage in power system are analyzed briefly, base principle of voltage class selection and evolution are described.Secondly, with arrester and closing resistor to limit synchronizing switching over-voltage on the first 1000kV UHV AC transmission pilot project in China from Southeast Shanxi via Nanyang in Henan province to Jingmen in Hubei province is researched with ATP-EMTP separately in this paper, the result of simulation indicates that the multistage closing resistors strategy or MOA with rated voltage 828kV in the both ends and mid of the line strategy is good for limiting the overvoltage of 1000kV UHV AC transmission system.