High resistance surface coating of solid insulating components for HVDC metal enclosed equipment

The field distribution of DC insulation systems is controlled by the conductivity /spl kappa/ of the insulation material. It can be improved by using a high resistance surface coating. Furthermore this coating can prevent charge accumulation on the surface of the insulation. This paper reports the investigations regarding such a coating that is subjected to HVDC stress. The influence of voltage, electrical stress and temperature on the resistance of the coating are investigated.