一起220 kV GIS断路器放电故障分析与试验研究

摘要

Due to large short-circuit energy and serious erosion of faulted equipments,it is unable to determine fault position and direct reasons when high voltage gas insulated metal enclosed switchgear and controlgear(GIS)happens large current short-circuit fault. In view of this,this paper analyzes and studies SF6 decomposition product of faulted GIS in some 220 kV substation and attachments on surface of faulted region by using energy disperse spectroscopy method. Combining disassem-bly return to depot and considering composition of breaker device,it analyzes reasons for causing the accident. Meanwhile, it studies impact on dielectric strength of GIS by ferruginous metallic particles and criticality of insulation deterioration in 220 kV GIS. The result indicates that the direct reason for the accident is ferruginous metallic particles in GIS breaker and the indirect reason is relax control on installation which makes GIS with defects. With the same voltage level,impact on die-lectric strength of GIS by metallic particles is more obvious,insulation deterioration is more severe and the GIS is liable to come up flashover.%高电压等级的气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear and controlgear,GIS)在发生大电流短路故障时,常常由于短路能量较大,故障设备烧蚀严重而无法确定故障位置和直接原因。针对此,采用扫描电子能谱(energy disperse spectroscopy,EDS)法对发生故障的220 kV某变电站 GIS 设备 SF6气体分解产物及故障区域表面附着物进行分析研究,结合返厂解体,同时考虑断路器设备原件的成分组成,分析了造成事故的原因。同时,在实体220 kV GIS内试验研究了铁质金属颗粒对 GIS绝缘强度的影响和绝缘劣化的危险程度。结果表明：GIS断路器内存在铁质金属异物是造成事故的直接原因,厂内安装控制不严造成的带缺陷出厂为间接原因；在同一电压等级下,金属异物越大对 GIS 的绝缘强度影响越明显,绝缘劣化越突出,GIS 越易发生闪络事故。