特高压直流输电山区线路Z型杆塔与T型杆塔的比较

我国特高压直流输电工程途经大量山地,雷电活动频繁,而常规T型塔在山区的绕击跳闸率较高,为此针对溪洛渡—浙西特高压直流输电山区线路设计了一种新型杆塔(Z型塔)。针对Z型塔,对比T型塔,采用改进电气几何模型与ATP-EMTP软件,计算分析了反击、绕击耐雷性能及其影响因素,同时采用CDEGS软件结合公式法对Z型塔的电磁环境做了评估。结果表明:Z型塔的反击耐雷水平很高,绕击耐雷性能明显优于T型塔,因此Z型塔的整体防雷性能明显优于T型塔。在呼称高最小时Z型塔各项电磁环境参数均达标,且均优于T型塔。可见Z型塔更适合在山区使用。

Comparative Research on Z-Type Tower and Traditional T-Type Tower for UHVDC Transmission Lines Located at Mountain Areas

UHVDC transmission lines in China have to pass through a lot of mountainous regions where lightning strokes frequently occur,thus the shielding failure outage rate of UHVDC transmission line adopting conventional T-type towers and passing through mountainous region is high.For this reason,a new type of tower possessing a new type of tower head,namely the Z-type tower,is designed for the part of UHVDC transmission line from Xiluodu to Zhexi,which passes through mountainous regions.The lightning withstand performances of back flashover and shielding failure of T-type tower and Z-type tower as well as their impacting factors are researched by the simulation in which the calculation model of shielding failure is established by electrical geometry model(EGM) and the calculation model of back flashover is established by ATP-EMTP,meanwhile combining CDEGS software with formula method the electromagnetic environment of Z-type tower is assessed.Research results show that the Z-type tower’s lightning withstand performances of back flashover is high,therefore the overall lightning withstand performance of Z-type tower is evidently better than that of T-type tower.Under the lowest nominal height of tower,the electromagnetic environment parameters of Z-type tower can reach national environmental standards and are better than those of T-type tower.Thus it can be seen that the Z-type tower is more suitable to be applied in mountainous regions than T-type tower.