Lightning Protection Performance of Shielding Failure of 1 000 kV Transmission Line

In this paper,the electrical geometry model is used to analyze the lightning protection performance of shielding failure of 1000kV transmission line.Firstly,a modified electrical geometry model algorithm is presented to calculate the projection length of shield and exposure arc for different lightning current,as well as the corresponding shielding failure trip-out rate.Then,based on Huainan-Wannan-Zhebei-Huxi 1000kV UHV transmission line project,the impacts on the lightning protection performance of shielding failure is analyzed in terms of different terrain,shielding angle and tower height.As shown by the calculation results,the performance is best in plain areas,while worst in mountainous areas;the shielding failure trip-out rate increases with shielding angle and tower height′s increment.Finally,the value of shielding angle is recommended for Huainan-Huxi 1000kV UHV transmission line project.UHV;1000kV transmission line;lightning stroke;electrical geometry model algorithm