220 kV地线连接金具断裂事故分析

Analysis on Link Fittings Fracture of 220 k V Ground Wire

地线金具主要起到传递机械和电气负荷的作用,正常情况下地线的连接金具使用周期为20~30年。针对某工程220kV架空线路中地线连接金具发生断裂导致整条线路掉落的事故,通过对失效连接金具及地线的宏观观察、化学成分分析、扫描电镜以及能谱分析等方法,分析了该连接金具发生断裂的原因。结果表明:构架侧的耐张线夹钢锚和直角挂板的连接部位经长期粘着磨损,同时存在不合理的连接方式使磨损加速,导致连接螺栓尺寸减小,最终无法承受地线张力而断裂。

Link fittings of ground wire,with the service life of 20~30 years,are used for transmitting mechanical load and electrical load.In view of the line drop due to link fittings fracture in a 220 kV overhead transmission line,macro observation,chemical composition analysis,scanning electron microscopy and energy spectrum analysis are employed to check the fracture causes.The results show that the tension clamp anchor and the connection area of the clevis by the side of the framework adhere and wear long,which was accelerated due to improper connections and decreases the size of the connecting bolts.Eventually,the link fittings fractured because of over-tension of the ground wire.