Study On Lightning Protection Of Double Circuit For Transmission Lines Of DA-Xing Electric Company

With the development of the national economy and the rapid growth of the power load as well as the increasingly crowded line corridor, double circuit lines on the same tower or even multiple circuits in HV, EHV transmission lines have been widely used in China, especially used in the large cites such as Beijing and Shanghai where line corridors are much crowded. However, the long-distance transmission lines are vulnerable to lightning strikes and other disasters.This paper firstly introduces the basic mechanism of withstanding lightning performance of transmission lines, and then summarizes the relevant parameters of lightning and relevant theories of lightning calculation. According to investigation and research, one summarizes lighting distribution of Beijing grid and the related lightning data over the past several years. Then, after the lightning accident of double-circuit transmission line(110kV) in Bejing grid is emphatically analyzed, one analyzes the factors which affect the lightning protection of double-circuit lines and proposes engineering measures that can be applied to Beijing grid to improve the lightning withstand level of double-circuit transmission line.In order to further study the lighting protection technology of transmission line, this paper establishes a double-circuit transmission line tower struck by lightning accident corresponding to Beijing grid for the110kV model based on ATP/EMTP software to which simulation analysis is performed according. The results show that the analyzing results are good agreement with certain characteristics of the grid after being struck by lightning coincide, which indicates that the method has come instructive significant for practice engineering.Comprehensive studies show that terrain features, large corner towers, strong thunderstorms and poor contact of tower grounding may result in lightning vulnerability of transmission line. Therefore, the protection measures, such as reducing tower grounding resistance and installing line arrester as well as installing anti-around-strike lightning rod, can improve the level of the lightning withstand of the double-circuit overhead line effectively. This paper provides a reference for those who engage in transmission line design, operation and the maintenance units.