一起500kV直线小转角塔架空地线断股原因分析及对策

Reason Analysis and Countermeasures of a Broken Strand of Overhead Ground Wire on 500 kV Straight Line Small Angle Tower

针对500 kV南玉Ⅱ线直线小转角塔架空地线断裂落地故障,通过计算、分析,得出故障的主要原因是外角侧架空地线在风偏工况下与地线支架角钢斜材间距离过近,导致地线与斜材发生摩擦断股,同时分段绝缘架空地线会通过地线支架放电,引起架空地线和塔材发热受损,最终导致剩余良好钢股最大使用张力小于地线运行张力而发生断裂落地事故。对受损的架空地线悬垂串金具、地线支架斜材及地线进行了修复、更换处理,并提出了防止此类事故发生的措施和建议。

Aiming at the breaking and falling to ground fault of overhead ground wire on 500 kV NangyuⅡstraight line small angle tower,the reason is found by calculation and analysis which is that the distance between the overhead ground wire at the outside and the angle steelinclined material of the ground wire support is too closer under the winddeflection condition,which caused the friction broken strand of ground wire and inclined material,and at the same time the sectional insulation ground wire will discharge through the ground wire support which caused the heating damage of overhead ground wire and tower material,and finally caused the breaking and falling to ground accident after the max using tension of the remaining good steel strands are smaller than the ground wire running tension.Damaged suspension string fittings of overhead ground wire and inclined material of ground wire support were fixed and replaced.Measures and suggestions on preventing such similar accidents are proposed.