Details

This masters thesis investigates the electric field strength distribution in 220 kV surge arresters equipped with polymer and porcelain insulation housings, using finite element simulation in COMSOL Multiphysics. Two full-scale 3D models of surge arresters were constructed: one with a porcelain shell and one with a silicone rubber (polymer) housing. Both models were subjected to identical boundary conditions corresponding to the 220 kV operating voltage class. The simulation produced two-dimensional field maps and one-dimensional axial profiles for each design variant. The porcelain insulator exhibited a peak localized electric field of 23.8 kV/m at the sharp ceramic edge near the upper metal fitting. The polymer insulator, under identical conditions, reached a peak of 19.2 kV/m — a reduction of 19.3%. Axial field profiles extracted along the insulator axis showed that the polymer variant produces a slightly higher on-axis field E z of  approximately 5,880 V/m compared to 5,677 V/m for porcelain (a 3.6% increase). However, the normal surface field E n at the lower end cap recovered to only 1,151 V/m for porcelain versus 1,748 V/m for polymer, while the porcelain design showed much stronger localized concentrations at shed edges due to its geometry.