35 kV GIL通管绝缘子局部放电问题成因分析及其反措

Cause Analysis and Countermeasures for Partial Discharge in Insulator of 35 kV GIL Tube

国网上海市电力公司检修公司对某220 kV变电站进行特高频检测和超声波检测时,发现B公司生产的35 kV GIL通管存在局部放电问题。对气体绝缘母线(GIL通管)的结构特点进行分析,发现问题成因在于绝缘子的金属嵌件与设备壳体之间因热胀冷缩而产生气隙,出现悬浮电位;对GIL通管的应用情况进行统计,发现悬浮电位导致的局部放电是造成GIL通管非计划停役的主要原因。提出在绝缘子支撑钉中钻孔并加装伸缩弹簧的反措,并应用于某绝缘子,加压测试验收通过;使得GIL通管的结构缺陷得以解决,保证了电网的安全稳定运行。

Inspection ＆ Maintenance Company, SMEPC inspected a 220 kV substation using ultrahigh frequency and ultrasonic wave, discovering that the 35 kV GIL tube produced by Company B has partial discharge problems. By analyzing the structure characteristics of GIL tube, it is found that the main cause of the problem lies in the air gap between the metal insert of insulator and the shell of equipment caused by thermal expansion and cold contraction, which exerts suspended potential. The application status quo of GIL tube is statistically analyzed, and it is found that the partial discharge caused by suspended potential is the main cause of the unplanned shutdown of GIL tube. The countermeasures of drilling holes in insulator support pins and installing flexible springs are put forward, and it is applied to an insulator and passed the pressure test. The congenital and familial structural defects of the GIL tube are solved, which will ensure the safe and stable operation of the power grid.