云南电网500kV地线绝缘化线路绕击耐雷性能分析

Analysis on Lightning Protection Performance of Shielding Failure for 500 kV Ground Wire Insulated Transmission Line in Yunnan Power Grid

输电线路覆冰是造成线路跳闸的重要原因之一。云南电网公司通过对500 k V输电线路进行地线绝缘化改造,实现了线路地线的直流融冰。由于地线绝缘化改造过程中,地线会通过地线绝缘子悬挂于杆塔塔头处,导致地线高度降低,进而使得输电线路的保护角增大,影响线路的绕击耐雷性能。通过EMTP-ATP平台计算5种不同塔型地线绝缘化改造前后的绕击耐雷水平,并通过电气几何模型(electric geometry model,EGM)计算这些塔型的绕击跳闸率。结果表明:地线绝缘化改造对线路绕击耐雷水平影响较小,但是对绕击跳闸率影响较大。

Transmission line icing is a main reason that causes transmission line's trip-out. Ground wire DC ice-melting of 500 kV transmission line in Yunnan power grid is realized via insulating ground wire. During ground wire insulation renovation process, ground wire will be suspended on the tower head through ground wire insulator, so the height of ground wire will be lowered, which leads to an increase of the protection angle of transmission line, thus lightning protection performance of shielding failure for the line will be affected. 5 different tower types'shielding failure lightning withstand level are calculated via EMTP-ATP before and after ground wire insulation renovation, and the shielding failure trip-out rate of these tower types is calculated via electric geometry model (EGM). The result shows that ground wire insulation has little effect on shielding failure lightning withstand level, but has great effect on shielding failure trip-out rate.