中文摘要：

直流输电线下合成电场计算方法中，上流有限元方法具有较强的适应能力，得到了广泛应用，但其计算效率尚有待提高。为获得较高的计算速度，该文根据上流有限元算法的特点，采用节点编号优化与Cholesky分解相结合的求解泊松方程的直接方法，反复求解泊松方程时较矩阵方程迭代算法有较大优势；采用合理的电荷密度更新策略，减少了迭代所需的收敛次数。这些方法综合应用，获得了较高的计算速度，1．5万节点的双极6分裂特高压直流输电线路合成电场算例，计算时间低于5S。在算例中该算法显示出对电荷密度初始值具有较好的鲁棒性。

英文摘要：

Among total electric field solution algorithms, upstream finite element method （FEM） has good adaptive capacity, and was widely used, but the calculation efficiency is needed to improve. In order to obtain high calculation speed, according to the particularity of the upstream FEM method, Poisson equation direct solution method together with node encoding optimization and Cholesky decomposition was adopted, and when solving Poisson equation repeatedly, the advantage is remarkable compared with matrix equation iterative solution method. Reasonable charge density updating strategy was adopted and the number of iterations was reduced. With integrated application of above methods, high calculation speed was obtained. To solve 15 000 nodes scale total electric field problem of bi-polar 6 buddle UHVDC lines, the time cost was less than 5 s. The algorithm shows good robust to the initial value of the charge density in the numerical cases.