Finite-element modelling of distribution ZnO surge arresters

Studies of voltage distribution and evaluation of the capacitive network for gapless distribution zinc oxide (ZnO) surge arresters were numerically conducted by a finite element method (FEM). This paper addresses questions related to performance optimisation of these arresters with polymeric housing. The voltage distribution in the non-conducting state is given including the effect of changing ZnO permittivity and of external field stress control. Different high-voltage electrode configurations are suggested to improve the voltage distribution efficiency. Modelling of pollution effects and combination of two arresters in series are also examined. Finally, the capacitive network is evaluated for the modelled arrester.