20KV开关柜起火原因分析

Analysis of Fire Cause of 20KV Switchcabinet

通过现场调查、事故记录审查、成分分析、熔痕金相分析等鉴定分析手段,找出开关柜事故原因。母线、母线接头、母线接头螺栓的材质不同,不同材质其电阻率及导电率的差异,导致在大负荷流过三种材质的结合处而未紧固的情况下产生高温,致使母线绝缘层加速老化,而在绝缘层被破坏的情况下,绝缘水平不够导致母线相与相之间发生放电现象,从而致使相间发生瞬间短路故障,又由于是备投装置中备投方式中过流闭锁,备投选择退出,导致故障范围扩大,从而发生火灾。

Through the appraisal analysis methods such as the field investigation,accident record review,componentialanalysis,metallographic analysis,find out switchcabinet is the cause of the accident.Different materialof busbar,busbar connector,busbar joint bolt,and the different of resistivity and conductivity,lead to thehigh temperature in heavy load flow through the junction of three kinds of material without fastening and thebusbar of the insulation layer accelerated ageing.Under the condition of the damaged insulation layer,Insulationlevel is not enough lead to the discharge of the phase busbarfacies.Thus,alternate with instantaneous shortcircuit fault.Because automatic switch device for making way of flow in the closure,automatic switchoptout,lead to failure enlarge and a fire.