Electric Strength Enhancement Using Low-conductive Coating on Hard Dielectric Insulation

Application of a thin low-conductive coating to hard dielectric insulation allows increasing the breakdown voltage. A surface charge is induced on the coating. The induced surface charge can smoothen the electric potential. The electric field intensity is reduced in this case and becomes more uniform. However, there is an issue of coating parameters selection: conductivity and spatial dimensions. A thin low-conductive coating with given parameters can behave as either a dielectric or a conductor depending on the characteristic time of the voltage change: If the time is very large, the coating behaves as an ideal conductor. The strong electric field appears on the coating edges in this case and decreases the electric strength. If, however, the characteristic time of voltage change is very…