某500 kV输电线路双回路直线塔右侧悬垂线夹断裂导致地线及OPGW光缆掉串。通过体视显微镜、光学显微镜、自动硬度计、扫描电子显微镜等对悬垂线夹断裂的原因进行了分析。结果表明:悬垂线夹紧固螺栓腐蚀严重,金具护套的铝合金材质不合格。螺栓磨损区域表面存在异常组织回火索氏体,表明螺栓曾经历过高温。综合分析表明,地线腐蚀引起的导通不良和断路是导致线夹护套磨损断裂的根本原因。

The suspension clamp on the right side of the double circuit tangent tower of a 500 kV transmission line broke, causing the ground wire and OPGW optical cable to drop. The cause of the suspension clamp fracture was analyzed by stereo microscopy, optical microscopy, automatic hardness tester, scanning electron microscopy. The results showed that the fastening bolts of the suspension clamp were corroded seriously, and the aluminum alloy material of the metal fitting sheath was unqualified.There was abnormal tempered sorbite on the surface of the bolt wear area, which indicated that the bolt had experienced high temperature. Comprehensive analysis showed that, poor continuity and open circuit caused by ground wire corrosion were the root causes of the abrasion and fracture of the clamp sheath.