一起主变有载开关触头接触不良缺陷的分析

Analysis of Defect of Poor Contact for Main Transformer Load Switch

某地110 kV站1号主变停电检修前调控中心对该主变进行调档时发现总是出现"滑档"现象,停电后高压试验人员对该主变进行高压侧绕组(110 kV侧)直流电阻测试时发现,有载分接开关在奇数分接位置时的绕组相互问差别数据较上次试验均有明显的增长,最大差别达到1.77%。现场吊检发现切换开关室内壁上C相奇数的静触头及切换开关上对应的静触头在垂直方向和水平方向稍有倾斜,且触头上有明显的烧蚀痕迹。现场及时进行了处理,消除了隐患。

When adjusting the shift of No.1 main transformer at 110 kV substation,the control center always found the ＂sliding shift＂ phenomenon before the substation was shut down for inspection.After power cut,the test personnel measured HV winding＇s DC resistance,and found when the load tap-changer was at odd number tap position,the difference of winding data was larger than that of the last time,the largest reached to 1.77%.They found the static contact of c-phased odd number at change-over switch inner wall and the static contact of change-over switch were inclined in vertical direction and horizontal direction,and the contacts were obviously ablated.On the site,the treatment was taken to remove the hidden dangers.