Advanced Finite-Element Method Employing a Singularity Function for Triple Junction Problems

A triple junction, joining place of a conductor, insulator, and gas substance, is a critical place with low dielectric strength in a high voltage apparatus. Around this triple junction, the electric field intensity is abruptly increased and the breakdown phenomena can be easily observed. To predict the breakdown characteristics of the triple junction, it is essential to estimate the distributions of electric field intensity with very high accuracy. In this work, to more accurately evaluate the electric field around the triple junction, we propose an advanced FEM (A-FEM) adopting a singularity function combined with the conventional FEM augmented with only one unknown variable.