Novel techniques for treating singularity problems in the boundary element method applied to electric field evaluation within the tank of a power transformer

Different shapes of the boundary surfaces within the tank of power transformers are classified into flat and round categories. By defining a surface charge distribution on the surface of the elements, suited in forming each type of those surfaces, the governing potential and field intensity equations are derived. The proposed surface charge distribution functions are such that the continuity of the charge distribution is guaranteed on the boundaries of the adjacent elements. Then by introducing different techniques, singularity problems on the integrands of the elements due to the flat and round surfaces are essentially solved. Fulfillment of these techniques leads to a quick evaluation of the electric field. Analysis of two typical examples indicates the high accuracy of these techniques. Finally the electric field within the tank of a power transformer is evaluated, based on the boundary element method (BEM) in which the above mentioned techniques have been used.