沙湾水电站4号机组定子绝缘性能降低原因分析与处理

Analysis and Treatment of Insulation Resistance Degradation of the Stator in No.4 Generator Unit in Shawan Hydropower Station

对沙湾水电站4号水轮发电机组定子绝缘性能下降的现象,结合机组历年运行及大修的实际情况,分析了定子绝缘性能下降的原因。针对机组中性点穿墙处起支撑和隔离作用的环氧板被油污浸泡后导致机组停机时定子绕组吸潮的问题,采取了对环氧板进行清洗、打磨、刷188绝缘漆的处理方式,回装后试验合格,投入运行后发电机没有出现任何异常现象。

Insulation resistance degradation of the stator is observed in No. 4 generator unit in Shawan Hydropower Sta- tion. Based on the practical operation and overhaul conditions, possible reasons of this fault are analyzed. It is found that the epoxy resin board, which is located at the place that the neutral point of the unit crosses the wall and serves as the support and isolation, is soaked with the oil stain. Thus, the stator windings will absorb moisture when the unit is shut down. Accordingly, the epoxy resin board is cleaned, abraded and coated with 188 insulating varnish. After the treatment, the generator unit operates well.