一起低压电气设备事故分析

Analysis of a low-voltage electrical accident

通过一起低压配电设备事故的分析表明,低压开关柜的插接头,在大电流下易发生接触面氧化和过热变形并引发事故。而变压器继电保护为满足高压侧短路时与熔断器-接触器(F-C)开关的时限配合关系,难以兼顾低压侧短路时的快速性,使得间断性的故障不能切除。又由于F-C开关熔断器配置不合理,导致低压设备故障时完全失去保护,造成事故的扩大。在继电保护配置、熔断器选择以及检修维护方面提出了一些防范措施。

The deep analysis of a LV（Low Voltage） distribution equipment accident indicates that, the surface oxidation and overheat deformation of LV switch board connectors may happen under big current,which causes accident. To satisfy the time coordination ＇relation with F-C（Fuse- Contactor） switch during high voltage side short-circuits,transformer protection may not be able at the same time to satisfy the rapidity during low voltage side short-circuitS,which causes the temporal fault remained. Furthermore,the use of improper F-C switch fuse may lead to total protection loss, which causes accident spreading. Some countermeasures are proposed in protection configuration, fuse selection and maintenance.