【摘要】 讨论了直流接地极双极转单极大地方式运行时，偏磁电流对近区变压器励磁特性的影响。基于场路耦合原理建立了变压器直流偏磁联合仿真模型，分析了接地极单极大地方式运行对交流电网以及变压器励磁特性的作用机理。通过仿真模型分析，结果表明：直流接地极双极转单极大地方式运行时，流过交流电网的偏磁电流为随时间变化的脉动型直流电流，其侵入变压器绕组造成了励磁电流也发生脉动变化，随着脉动直流幅值的增加，变压器励磁电流峰-谷间差值也逐渐增大。在直流接地极运行方式调整时，建立的仿真模型可以对交流电网直流偏磁水平监测和变压器励磁特性评估提供一定依据。更多还原

【Abstract】 The influence of magnetic bias current on the excitation characteristics of near-field transformers in the DC grounding electrode from bipolar to unipolar earth mode was discussed. Based on the principle of field-circuit coupling,the DC magnetic bias co-simulation model of transformer was established and analyzed the action mechanism of grounding electrode unipolar earth mode on AC power network and transformer excitation characteristics. Through analysis of the simulation model,the results show that when the DC grounding pole from bipolar to unipolar earth mode,magnetic bias current flowing through the AC power grid is pulsating DC current that varies with time,its instrusion into transformer winding causes the excitation current of transformer winding fluctuation change,with the increase of pulse DC amplitude,between transformer excitation current peak and valley difference also gradually increased. When the operation mode of DC grounding electrode is adjusted,the simulation model can provide certain babis for the level monitoring of AC power network DC magnetic bias level and the evaluation of transformer excitation characteristics.更多还原