强风区750kV复合绝缘子伞裙破坏机制分析研究

Analysis on Fracture Failure Mechanism of 750 kV Composite Insulator Sheds Utilized in a Storm-hit Region

为研究强风区复合绝缘子伞裙根部断裂故障的产生机制,进行了现场故障情况分析、材料疲劳龟裂实验、流固耦合仿真计算以及绝缘子伞裙特殊结构下的断裂问题分析。研究发现经过平均风速高于30m/s强风区的新疆750kV高压输电线路中,复合绝缘子出现大规模伞裙根部断裂故障,最严重的单根绝缘子有效爬距损失达20.4%。研究结果表明:常规绝缘子硅橡胶材料耐疲劳性能较差,在强风中绝缘子伞裙会出现大幅摆动现象,该状况导致伞裙根部承受严重的应力集中问题,长期的循环应力作用使伞裙根部材料出现疲劳裂纹,最终发展为伞裙根部断裂故障。该实验研究结果与现场故障现象吻合度较高,为进一步解决伞裙断裂故障提供了理论基础。

This paper provided a explicit explanation of composite insulator sheds fatigue failure mechanism in storm-wind region. Through the work of field research on the sheds fatigue failure, experimental study on rubber material fatigue crack, simulation with fluid-solid interaction of sheds and the static deformation of the special shed structure, it’s found that large amount of composite insulator faced with fatigue fracture problem on the 750 kV EHV transmission lines across particular storm-wind region with the mean wind velocity over 30 m/s in Xinjiang, the most serious case of single insulator was that the loss of valid creepage distance reached 20.4%. The test results show that the insulator silicon rubber had bad performance on anti-fatigue property. The fluid induced oscillation of insulator sheds in storm wind brought about the stress concentration problem at the root area,the application of cycled stress produced initial fatigue crack at the stress concentration area which lastly developed into fracture failure. The study results fitted well with field investigation, this work would provide a theoretical foundation for the solution of the sheds fatigue problem.