悬吊式电容塔连接导线断裂原因分析

±800 kV某换流站遭受台风袭击,直流滤波器场悬吊式电容器塔C1低压端发生了导线断裂故障,导致直流滤波器跳闸退出运行。本文通过开展断裂导线的扫描电镜(SEM)检测、化学成分(ICP-OES)检测等,分析了断裂机理;建立电容器塔有限元模型,计算分析风载荷下电容器塔结构响应。结合仿真计算结果,最终得出导线断裂原因为设计过程中未考虑到电容器塔在风荷载工况下存在位移。在强风作用下,电容器塔摇摆使铝绞线受到拉伸和挤压,长时间影响造成疲劳损伤、拉断。建议新建直流工程,在前期设计过程中应充分考虑电容器塔位移及长期运行要求,提高该段导线的设计裕度。

Fracture Analysis on Connecting Conductor of Suspension Tower of DC Filter Capacitor Bank

The ±800 kV converter station was attacked by typhoon and the conductor fracture fault was occurred at C:low voltage terminal of suspension capacitor tower of DC filter capacitor bank,causing the DC filter to trip and out of service.In this paper,the fracture mechanism was analyzed by way of scanning electron microscope and chemical composition(ICP-OES)detection ect.The finite element model of capacitor tower was set up and the structural response of the capacitor under wind load was calculated.According to the.simulation calculation results,the reason for fracture of conductor is that during the design period the displacement of the capacitor tower under wind load was not considered.The swing of the capacitor tower under strong wind keeps the aluminumstrand stretched and extruded and causes fatigue damage and fracture due to long time It is suggested that the displacement of capacitor tower and the requirement of long-term operation should be fully taken into account so to improve the design margin of this conductor during the preliminary design for a new DC project.