改进EGM模型对特高压输电线路的适用性与验证

Applicability and verification of an improved EGM model for UHV transmission lines

为了更准确地分析我国特高压输电线路雷电绕击屏蔽性能,基于我国长空气间隙放电试验数据和雷电回击观测数据,建立考虑地形条件的适应于大尺寸输电线路雷电屏蔽性能评估的改进电气几何模型(electric geometry model,EGM)并进行验证,将击距公式修正为rs=0.13(I^(2)+40I)^(0.814)。改进EGM模型对超、特高压输电线路三相导线的雷电绕击率计算结果与日本实际线路雷击观测数据及我国平原、山区特高压输电线路雷击模拟试验数据具有一致性,验证了改进EGM模型的适用性。采用改进EGM模型评估了杆塔型式、山坡陡度对我国特高压线路绕击跳闸率的影响。计算结果表明,采用SZ322型杆塔的绕击跳闸率高于采用SZT1型杆塔,且特高压线路绕击跳闸率随山坡陡度的增大而增大。EGM模型的修正以及计算方法的优化,对我国特高压输电线路雷电屏蔽性能的设计具有一定的指导意义。

To analyze the lightning shielding performance of UHV transmission lines in China more accurately,based on the long air gap discharge test data and lightning return stroke observation data in China,an improved EGM model suitable for lightning shielding performance evaluation of large-scale transmission lines considering terrain conditions is established and verified.The strike distance formula is modified to rs=0.13(I^(2)+40I)^(0.814).The calculation results of lightning shielding failure rate of three-phase conductors of EHV and UHV transmission lines by the improved EGM model are consistent with the lightning observation data of actual lines in Japan and the lightning simulation test data of UHV transmission lines in plains and mountains of China.This verifies the applicability of the improved EGM model.The improved EGM model is used to evaluate the influence of tower type and slope steepness on shielding failure trip rate of UHV transmission lines.The results show that the shielding failure trip rate of SZ322 tower is higher than that of SZT1 tower,and the shielding failure trip rate of a UHV line increases with the increase of slope steepness.The correction of the EGM model and the optimization of calculation method in this paper have a certain guiding significance for the design of lightning shielding performance of UHV transmission lines in China.