35kV所用变线圈内部断线后铁心磁通变化分析

Analysis on Core Magnetic Flux Variation upon Inner Coil Disconnection in a 35 kV Substation Transformer

以35 kV Dyn11型所用变为研究对象,分析了所用变在运行过程中发生线圈内部断线时,铁心磁通分布及高低压侧电压和电流的变化情况。研究表明,线圈内部断线故障不会明显改变低压侧电压和电流,也不会明显改变高压侧线电流,是一种故障特征不明显的缺陷。由于所用变发生线圈内部断线故障时,其实际可用容量衰减较大,在日常运维过程中,要通过红外测温等工作加强对所用变线圈本体的探查,尽早发现此类缺陷。

Taking a 35 kV Dyn11-type substation transformer as the research object,analyses are conducted on the core magnetic flux distribution as well as the variation of voltage and current on the high-voltage and low-voltage sides when a fault of inner coil disconnection in the transformer occurs during operation.The study shows that it is a defect without obvious fault characteristics as the inner coil disconnection will not significantly change the voltage and current on low-voltage side,nor will it sharply alter the line current on high-voltage side.Since the available capacity of the transformer is attenuated greatly when the inner coil disconnection occurs,monitoring the coil body of substation transformer would be strengthened during regular inspections such as infrared temperature measurement so as to detect such defects as soon as possible.