110kV变压器内部过热故障的分析及处理

在发现一台110 kV变压器油中溶解气体色谱分析数据异常后,应用三比值法判断变压器内部存在高温过热故障,结合色谱分析数据、运行历史、高压试验等手段,逐步查找确定故障部位.通过吊罩检修,找到了铁心外引接地铜片与旁边铁轭上表面搭接,形成铁心片间短路的故障点,并重新对铁心接地外引线进行了固定,成功消除了主变故障.分析故障发生原因,得出区分铁心片间短路与铁心多点接地的重要证据,为今后同行业同类型变压器故障判断提供了参考和经验.

Analysis and processing of 110 kV transformer internal overheat failure

After discovered abnormal data from a 110 kV transformer with dissolved gas chromatographic analysis, inner high temperature overheating fault of transformer is diagnosed with three ratio methods. Combined with chromatographic analysis data, operation history, high pressure test means and more, the fault position is gradually fixed. Through removing cover by crane, the lap was found in the place of grounding copper shce of magnetic core to upper surface of iron yoke nearby for its short circuit in failure point. And then, grounding copper slice of magnetic core was fixed again, the main transformer fault successfully eliminated. The analyses of failure reasons show the important difference of evidence between short circuit from magnetic core pieces and multipoint grounding from magnetic core. Reference and experience can be provided to similar trade for transformer faults detection.