Numerical performance analysis of semiconductor coatings for corona suppression

Corona is initiated in high field regions. To suppress corona or to increase the corona inception voltage in HV insulators or bushings, suitable semiconductor coatings, able to relieve high electric fields, are commonly used. The choice of appropriate materials to be used for the most effective corona suppression is typically made on the basis of expensive and time consuming trial and error tests or on the basis of approximate theoretical analysis. In this paper a guideline, based on the adoption of a suitable numerical method, is provided in order to lead to the optimal choice of the electrical characteristics of semiconductor materials for the most effective corona suppression.