FEM High-speed Method for Calculating Total Electric Field Below HVDC Lines

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.