紧凑型耐张塔防雷分支地线的若干问题

Discussion on Bypass Shielding Wire of Lightning Protection for Tension Tower in Compact Transmission Line

近年来设计的500kV紧凑型线路,为提高耐张塔防雷电绕击性能,在耐张塔地线支架外侧增加了跳线架,并加挂了防雷分支地线,但仍有分支地线从普通地线脱落,造成永久性单相接地短路故障的发生。从分支地线的受力模型、T接金具等方面分析了故障原因,提出采用预绞式T接线夹,优化分支地线安装位置、线长、弧垂等措施来提高线路运行的安全性。

In recent years, in order to reduce shielding failure of tension tower in 500 kV compact transmission line, jumper structure with bypass shielding wires is mounted on the tension tower. This leads to several single-phase grounding faults caused by the falling of bypass shielding wire onto the conductors. The faults reasons were analyzed from the aspects of the mechanical model and T-connection fittings. Several measures were proposed to improve operating security of the line, such as applying performed helical T-connection fittings, optimizing the installing position, length, sag of bypass shielding wire, and so on.