一起220 kV复合绝缘子芯棒断裂事故分析

Analysis of a Core Rod Fracture Accident of 220 kV Composite Insulators

复合绝缘子芯棒断裂事故会对输电线路的安全稳定运行构成严重的威胁。结合某220 kV线路复合绝缘子芯棒断裂事故,对断裂绝缘子及同批次产品进行了外观检查、性能试验、解剖检查、材料试验,分析了绝缘子芯棒断裂的原因及机理。结果表明:该绝缘子端部结构存在缺陷及密封性能不良的问题,导致芯棒玻璃纤维受到酸液侵蚀,逐渐产生应力腐蚀过程,在弱酸腐蚀及应力的共同作用下机械性能不断降低,最终整支芯棒发生断裂。针对芯棒脆断现象和长期机械性能不佳的问题,建议将复合绝缘子端部金具楔式结构逐批更换为压接式结构,并加强端部金具及护套的密封,以及采用无硼纤维耐酸芯棒。

The composite insulator core rod breakage accident poses a serious threat to the safe and stable operation of the transmission line.This paper combined with the 220 kV composite insulator breakage accident to carry out the visual inspection,performance test,anatomical inspection and material test of the broken insulator and the same batch of products and analyzed the causes and mechanism of the insulator core rod breakage.The results show that the end structure of the insulator has defects and poor sealing performance,which causes the mandrel glass fiber to be corroded by acid solution and gradually produces stress corrosion process.Under the joint action of weak acid corrosion and stress,the mechanical properties are continuously reduced and the whole mandrel ruptures.In view of the brittle fracture phenomenon of the core rod and the long-term poor mechanical properties,it is recommended to replace the composite insulator end fitting wedge structure into a crimping structure batch by batch,and to strengthen the sealing of the end fittings and sheath,and to use boron-free acidproof core rod.