一起220 kV组合电器绝缘击穿故障原因及分析

Cause and Analysis of Insulation Breakdown Fault of 220 kV Composite Apparatus

某500 kV新建变电站220 kV部分采用组合电器,在启动送电过程中发生绝缘击穿导致设备跳闸故障,严重影响正常电力生产秩序。为彻底查清故障原因并避免发生类似故障,在对故障单元拆解后从内部放电痕迹、绝缘拉杆及盆式绝缘子X射线探伤、故障单元耐压和局部放电试验、镀银层厚度检测、装配尺寸等方面进行分析,结合内部样品粉末检测报告后查明,由于在设备制造组装阶段工艺把控不严,没有将内部的金属颗粒完全清理干净,导致组合电器送电后发生绝缘击穿。事故暴露出组合电器制造单位未严格落实相关工艺管控要求,为防止其他设备发生类似故障,制造厂应采取相应的预防措施。

The composite apparatus is used in 220 kV part of a 500 kV new transformer substation.In the process of starting power transmission,the insulation breakdown causes the equipment to trip fault,which seriously affects the normal power production order.In order to thoroughly identify the fault reasons and avoid similar faults,after disassembly analysis of the faulty unit,it is analyzed from the view of internal discharge traces,insulation rod and basin insulator X-ray inspection,fault cell withstand voltage and partial discharge test,silver layer thickness detection,equipment size.Combining with internal sample powder test report,it is found out that the process control of the equipment manufacturing and assembly stage is not executed strictly,and metal particles inside are not completely cleaned up,resulting in insulation breakdown after the device is powered.It is exposed that the gas insulated switchgear manufacturer do not strictly implement the relevant process control requirements.To prevent similar faults from occurring on other devices,the manufacturer takes corresponding preventive measures.