Three-dimensional modeling of potential and electric-field distributions along an EHV ceramic post insulator covered with ice - Part I: Simulations of a melting period

The main objective of this paper is to determine the potential and electric-field distributions along a typical ceramic extremely-high-voltage post insulator covered with atmospheric ice during a melting period. Commercial software, Coulomb 3D, based on the boundary element method (BEM), was used for all of the three-dimensional modeling and simulations. It was demonstrated that the BEM is well suited for evaluating the effect of ice shedding on the potential and electric-field distributions along an ice-covered insulator during a melting period. The results obtained show that the length and number of ice free zones, also called air gaps, are the major parameters that affect the applied voltage distribution along an ice-covered insulator. The mean electric field per arcing distance, affected mainly by the air-gap lengths, can provide a good indication of the presence of partial arcing along the different air gaps.