220 kV SF6罐式避雷器局部放电异常案例分析及改进提升

Case Analysis and Improvement Measures of Partial Discharge for a 220 kV SF6 Tank Arrester

不同于一般瓷外套和复合外套避雷器,SF6罐式避雷器封装在组合电器内部,这不仅能够保护组合电器设备不受过电压侵害,还可以确保避雷器在金属外壳的保护下不受外界污秽、潮气等的侵蚀,然而由于肉眼无法直接观察避雷器,这种布置形式也给避雷器的巡视、监测与状态评估带来了一定的困难。当罐式避雷器在长期运行过程中产生内部局部放电时,若不能及时开展带电检测进行诊断识别,则有可能导致进一步发展。针对一起220 kV罐式避雷器装配工艺不良导致内部局部放电的案例,通过现场带电检测、返厂解体检查及仿真计算验证,对局部放电异常的现场检测、诊断识别、原因分析进行了全过程介绍,最终确认避雷器芯组装配偏心是导致局部放电异常的原因,并提出了针对性的改进措施。

The SF6tank arrester is encapsulated inside the combined electrical appliance,which can protect the combined electrical equipment from overvoltage,and ensure that the arrester is protected from external contamination and moisture under the protection of the metal casing. However,since the arrester cannot be directly observed,this arrangement brings certain difficulties for the inspection,monitoring and state assessment of the arrester.When the tank arrester generates internal partial discharge during long-term operation,and the live detection cannot be carried out in time for diagnosis and identification,it may lead to further development of the fault.Aiming at a case of internal partial discharge caused by poor assembly process of 220 kV tank arrester,the on-site live detection,return to factory disassembly inspection and simulation calculation verification were carried out.On this basis,the on-site detection,diagnosis and identification and cause analysis of abnormal partial discharge were analyzed in detail.It was confirmed that the assembly eccentricity of the arrester core group was the cause of abnormal partial discharge,and the targeted improvement measures were put forward.