中文摘要：

应用谐波平衡有限元法对电力变压器直流偏磁现象进行研究。根据稳态激励下电磁场的周期性,以谐波形式表达电路和磁场中的变量;通过对铁心磁阻率的谐波分解,建立了考虑场路耦合关系的谐波平衡有限元方程。通过直接求解激磁电流和磁矢量位的谐波解,分析了直流偏置量与直流磁通之间的关系并得到各次谐波状态下磁通分布的局部涡旋效应。同时应用爱泼斯坦方圈铁心模型进行了不同直流偏置量下的直流偏磁实验,计算结果和实验结果吻合较好,证明了该方法在直流偏磁现象研究中的有效性。

英文摘要：

In this paper the harmonic-balanced finite element method （HBFEM） was applied to study the DC bias phenomenon in power transformers. Variables in electric circuits and magnetic field were represented in harmonic forms duo to the periodic characteristic of electromagnetic field under steady-state excitation. The harmonic-balanced finite element equation was set up by means of the harmonic decomposition of magnetic reluctivity,considering the coupling of electric circuit and magnetic field. The harmonic solutions of exciting current and magnetic vector potentials were calculated directly to analyze the relationship between DC bias and DC flux. The local vortex characteristic of flux distribution in each harmonic was also presented. An Epstein frame-like core model was applied to carry out the DC bias experiment. A good agreement between calculated results and experimental data proves the effectiveness of HBFEM in the investigation of DC bias phenomenon.