Numerical Algorithm for Polarity Reversal Electric Field and Its Application

Aim To analyze the transient speciality of nonlinear, anisotropic, AC+DC coupling electric field, and to compare the withstand voltage strength of different insulation structures. Methods The transient process of polarity reversal is analyzed, considering the anisotropic property of oil immersed press board, a new finite element model based on Galerkin method is presented and verified. The model developed is applied to calculate the electric field distribution in four typical winding end structures of the converter transformer. Results The whole ring structure possesses the best insulation characteristics. Conclusion By introducing reasonable insulation components, insulation strength with the same surrounding sizes can be improved more than 30%.