某抽水蓄能电站主变直流偏磁现象及抑制措施研究

Research on DC Bias and the Corresponding Countermeasures of Main Transformer in a Certain Pumped Storage Power Station

直流偏磁是一种变压器非正常运行状态,简述了变压器直流偏磁产生机理及其不良影响;介绍了某抽水蓄能电站主变直流偏磁现象,并结合电站主接线形式、主变联接方式等实际情况,提出在主变中性点加装电容隔直自动投退装置的解决方法。该方法通过动态监测、实时自动投退隔直电容,在确保主变中性点有效接地的前提下,达到抑制侵入变压器直流电流的目的。隔直装置运行效果表明,该方法有效解决了变压器直流偏磁问题,保证了主变和电站的安全稳定运行。

DC bias is a kind of abnormal working state of the transformer.This article briefly described the generation mechanism of the transformer DC bias and its negative effects.The DC bias phenomenon of the main transformer of a certain pumped-storage power station was introduced.Combining together major relevant factors such as the main wiring form of the power station and the connection mode of the main transformer,the countermeasure of adding a capacitor DC automatic switching device at the neutral point of the main transformer was proposed.Through dynamic monitoring and real-time automatic switching of the DC blocking capacitor,this method achieved the purpose of suppressing the intruded DC current on the premise of ensuring effective grounding of main transformer′s neutral point.The practical operation of the DC blocking device showed that this method effectively solves the problem of DC bias of the transformer and ensures the safe and stable operation of the main transformer and the power station.