中文摘要：

提出了一种计算大型变电站接地网电磁场的快速算法。首先,该算法使用修正镜像法（modified image method,MIM）将待求模型所处的半无限有损空间化为均匀空间,从而避免了原电场积分方程中出现的索末菲积分计算。其次,借助快速多极子方法（fast multipole method,FMM）求解该电场积分方程,最后,利用共轭梯度法求解线性代数方程。在选取基函数及权函数时充分考虑了阻抗矩阵对称性和区组元素相互作用的平移不变性。与其他文献及CDEGS软件的计算对比结果,验证了该算法的正确性、适用性及有效性。

英文摘要：

A fast algorithm was presented to compute the electromagnetic fields around the substation grounding system.The modified image method was used,and the lossy half-space in which the model placed to be solved was converted to a homogeneous space.Then the Sommerfeld integrals contained in the original integral equation were avoided.The fast multipole method（FMM） was utilized to solve the governing electric field integral equation（EFIE）.The conjugate gradient method was utilized to solve the linear algebraic equations.Furthermore,the symmetry of the impedance matrix and the translational invariance of mutual impedance in near regions were considered when basis functions and weight functions were chosen.The validation of the proposed algorithm is performed by comparing the results with those in published references and calculated by the CDEGS software respectively.The numerical example shows the accuracy,flexibility and efficiency of the presented algorithm.