500 kV输电导线耐张线夹断裂失效分析

采用宏观检查、拉伸试验、金相组织检测、扫描电镜及能谱分析等方法,对输电导线耐张线夹断裂的原因进行了分析。结果表明,耐张线夹内钢芯和铝管的力学性能、显微组织及化学材质均正常,耐张线夹断裂失效的主要原因为钢锚表面存在较深压痕及明显弯曲变形,会使钢芯在变形点产生较大的应力集中和挤压摩擦损伤。长时间运行后钢芯受损程度加重,钢芯在变形处相继断裂,从而导致外部铝管断裂事故发生。

Failure Analysis on Fracture of Strain Clamp in 500 kV Transmission Line

The fracture reason of a strain clamp in 500 kV transmission line is investigated by macroscopic examination,tensile testing,metallographic examination,scanning electron microscopy and energy spectrum analysis.Results show that mechanical properties,microstructure and chemical composition of the steel core and aluminum tube are qualified and can satisfy the requirements of relevant standards.Repeated crimping trace and obvious bending deformation can be clearly observed on the surface of steel anchor,resulting in larger stress concentration and the extrusion friction damage of steel core.After long time running,the damage of steel core is aggravating and steel cores suffer the fracture successively,which leads to the fracture of external aluminum tube.Thus,the accident happens.