直流偏磁对葛洲坝电站主变压器的影响及抑制措施

Effect on DC Biasing on Main Transformers of Gezhouba Hydropower Station and Study on Restraining Measures

直流偏磁会导致变压器噪音增大、振动加剧,可能引起变压器局部过热甚至损坏。从与直流系统的联结情况、长江巨大水体的影响等方面分析了葛洲坝水电站主变压器受直流偏磁影响的可能性,并从磁路结构对三相五柱式变压器的抗偏磁能力进行了论证。论证结果表明,要改善葛洲坝电站2台联络变压器的直流偏磁状况,较为可行的措施是增加直流偏磁反极性补偿装置,向变压器中性点中注入反向直流电流,必要时还可使变压器降低工作点运行。

DC biasing can cause transformers noise increasing, vibration intensified, local overheating and even damaged. Considering the connection to DC system of the station and the influence of the enormous water of Yangtze River, it is analyzed whether main transformers of Ge-zhou-ba Hydropower Station can be affected by DC biasing. After that, the anti-bias ability of a three-phase five-pillar-core transformer is demonstrated from the magnetic structure. The result indicates that, to improve the two internuncial transformers＇ DC biasing condition, the feasible measure is adding an antipolarity DC biasing compensation device and injecting reverse DC current into the neutral point. The transformer also can operate at a lower operating point as accessorial measure when necessary.