Current transformer is one of the important equipment in power system,and is widely used in different voltage levels,its primary side is connected to the primary side of power system,and its secondary side is connected to the secondary system.Therefore it is both primary and secondary equipment,once main insulation fault of current transformer occurs,it will directly affect the reliability of power system operation.In this paper,based on a typical main insulation fault of 500 kV SF6 current transformer,combined with the disassembly of current transformer,a finite element simulation software named ElecNet of Infdytica is used to calculate and analyze the potential distribution and electric field,the process of fault is explained,it is revealed that air gaps within defective basin insulator cause partial discharge for a long time,which results in main insulation failure.The electric field of current transformer under normal working condition is detailedly analyzed,the fault process is revealed.The research achievements will be of great significance to guide the selection of 500 kV SF6 current transformer,and improve the operation reliability of power system.%电流互感器在电力系统各个电压等级应用十分广泛且非常重要,原边接入电网一次系统,副边接入电网二次系统,因此它既是一次设备,也是二次设备,一旦发生主绝缘故障将直接影响电力系统的安全稳定运行.针对一起500kV SF6电流互感器的典型主绝缘故障,结合设备故障后的解体情况,运用Infolytica的ElecNet电场有限元仿真软件,对SF6电流互感器躯壳内的电位、电场分布进行了计算与分析,解释了故障发展的过程,揭示了电流互感器盆式绝缘子内部存在气孔缺陷引起长期局部放电,进而导致电流互感器盆式绝缘子主绝缘失效的故障原因.既分析了产品正常工况下的电场分布,也对故障发展过程进行了解释,成果可指导500 kV SF6电流互感器设计校核,对保障电力系统的安全运行具有重要意义.
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