电力变压器直流偏磁现象形成机理及一种抑制措施的研究

Research on the Formation Mechanism and Suppression Method of Transformer DC Bias

直流偏磁是变压器的一种非正常工作状态,对电力变压器直流偏磁现象的形成及抑制措施展开研究具有重大的意义。本文基于容易遭受直流偏磁影响的单相变压器模型,模拟直流偏磁下变压器实际工作状态;研究了直流偏磁现象对变压器产生的影响,给出偏磁前后励磁电流及其各次谐波变化,并对偶次谐波增大原因进行了详细分析。提出一种利用两相磁性材料抑制变压器直流偏磁问题的方案,通过控制材料的磁状态实现对变压器内部偏磁磁通进行定向补偿,减小直流偏磁对变压器的危害。利用ANSOFT软件对所设计的变压器进行仿真实验,并制作具有直流偏磁补偿功能的新型电力变压器样机一台,对直流偏磁实施补偿试验;实验结果表明基于两相磁性材料的新型电力变压器对直流偏磁具有很好的抑制效果。验证了所提方案的可行性和正确性。

DC bias phenomena is an abnormal operating state of transformer, research on formation and suppression of transformer DC bias has a great meaning. Actual working state under DC bias is simulated on base of single-phase transformer model which is easily affected by DC bias; the influence on transformer generated by the DC bias phenomenon is studied, the change of excitation current and each harmonic are given before and after DC bias, the reason of even harmonics increased is analysised in detail. A scheme with a function of compensating the power transformer DC bias phenomenon on base of two-phase magnetic material is put forward. The DC bias is directional compensated by controlling the magnetic state of material, simulation of transformer is conducted using ANSOFT and a novel transformer prototype with DC bias compensation function is made, the DC bias compensation experiment is conducted. The simulation and experimental results show that this novel transformer could achieve a good compensation for the DC bias problem which verifies the correctness and feasibility of the proposed scheme.