Transformer electric field calculation using BEM and FEM

This paper presents the use of a self-developed solver based on boundary element methods (BEM) for electric field calculation of a transformer. Calculation of electric field is based on the approximation of charge density on the transformer winding. By obtaining the unknown distribution of charge density it is possible to calculate both the potential and electric field strength, as well as calculate the capacitance matrix. Linear functions are used as base functions and point-matching method is used and the integration is done both analytically and numerically. Additionally, commercial software based on finite element methods (FEM) is used for modelling the same problem to verify the obtained results. The problem is solved for a real transformer geometry by both BEM and FEM. The results are then compared and a short analysis of the application of both methods on this problem is given.