交叉跨越区段下方穿越线路绕击特性研究

Study on lightning shielding characteristicsof lines below cross-crossing sections

随着特高压线路的兴建,由于输电走廊的空间限制,不可避免地会出现特高压线路与500 kV交流线路交叉跨越的情况,且在穿越处下方500 kV输电线路的绕击性能与一般非跨越区段情况输电线路具有较大差异。本文基于电气几何模型法,对上方鼓形双回1 000 kV交流线路输电通道对穿越下方500 kV干字型线路的情况进行了计算,并分析了下方钻越线路避雷线架设方式对各相绕击率的影响。研究结果表明上、下方线路穿越中心点200 m范围内具有雷电屏蔽作用,且距离中心点越近,屏蔽作用越强。避雷线架设方式对各相绕击率影响的计算结果表明,被穿越的下方线路穿越点附近1基以内杆塔线路可以不架设避雷线。研究结果对特高压线路跨越的500 kV交流线路防雷设计提供参考。

With the construction of UHV lines,space constraints in transmission corridors inevitably lead to intersections between UHV lines and 500 kV AC lines.Notably,the lightning shielding performance of the 500 kV transmission line below the crossing differs significantly from the non-crossing sections.Based on the electro-geometric model,this paper simulates and examines the lightning shielding performance of an overhead double-circuit 1000 kV AC transmission line on an underlying double-circuit 500 kV AC transmission line.Further,the study evaluates the influence of the lightning arrester installation modes on the shielding failure rate in each phase below double-circuit 500 kV AC transmission lines.The findings indicate that both the upper and lower lines demonstrate lightning shielding within 200 m from the crossing′s central point.Moreover,the closer they are to the center.The calculation results of the influence of lightning arrester erection modes reveal that,for the line being crossed below,it′s feasible to avoid installing lightning arresters on towers within a distance of one base from the crossing point.These findings provide reference for the lightning protection design of 500 kV AC lines intersected by UHV lines.