高压直流输电单极大地回路运行产生的地电流会导致变压器直流偏磁, 引起变压器局部过热、振动加剧、噪声增大等不良反应。分析了直流偏磁对变压器影响以及抑制直流偏磁的主要方法,提出了抑制变压器直流偏磁的新装置拓扑,采用电位补偿原理，通过故障模拟仿真，完成了对整个装置的器件参数选型，为有关工程建设提供借鉴。

HVDC power transmission system that works in monopolar operation will generate neutral current causing DC magnetic biasing of transformer, which will lead to the adverse reaction of transformer, such as local overheating, vibration increase and noise increase. The influence of DC magnetic biasing on transformer and the main suppression method of DC magnetic bias are analyzed. The new device topology of supressing transformer DC magnetic has been proposed, based on the principle of DC electric potential compensation. Through the fault simulation, the parameter selection for devices has been implemented，which could serve as references to relevant projects.