KYN-35开关柜用LDJ-35类电流互感器结构性放电问题探讨

Discussion on the Structural Discharge for Type LDJ-35 Current Transformers Installed in Switchgear KYN-35

35 kV带触头盒的电流互感器,由于结构上的原因,若不采取有效的电场均压屏蔽措施,在进行绝缘试验或正常运行时,会在触头盒内腔中产生或强或弱的但较为明显的刷形甚至闪络放电现象,长期易产生污秽、积碳积尘,导致接地或相间短路等事故,影响对互感器本身主绝缘缺陷的正确判断,给系统的安全运行带来较大的隐患。对此放电机理进行分析,并提出改进方案。

This paper introduced 35kV current transformers with contact boxes, if no effective measures of electric field voltage-sharing shield are taken, the visible brush discharge, even flashover discharge, strong or weak, may appear in the cavity of contact box during the insulation test or normal operation due to the structure, in which case, after a long time, the dirt, carbon deposit or dust deposit may be generated and earthing or phase-to-phase short circuit accidents may occur. This will affect the determination of main insulation defect of the instrument transformers, and cause serious hazard to the safe operation of system. This paper analyzes the theory of discharge, and puts forward the proposal about improvement.