500kV练塘变电站直流偏磁影响及抑制变压器中性点直流偏磁方案的优化配置研究

摘要

高压直流输电单极运行产生的大地直流电场，在中性点接地系统变压器铁心中产生直流偏磁，对变压器的正常运行造成很大影响。结合上海500kV练塘变电站工程，比较了三种可行的抑制直流偏磁的方案，并根据仿真计算总结了小电阻接地方案的可行性。%The earth return monopolar operation of high voltage direct current transmission （HVDC） can cause continuous DC bias current in the transformer＇s neutral grounding and thus affect the safe operation. Three schemes of restraining DC bias based on the 550 kV Liangtanng Transformer Substation are compared and analyzed in this paper. After simulation and calculation, it is proven that the grounding scheme via small resistance is effective and feasible.