Measurement of key dielectric properties for surface PD model under HVDC

The discharge over dielectric interfaces popularly known as surface discharge is a very common defect type that is associated with its respective discharge pattern under AC voltages. However, the same designs behave differently under DC voltages leading up to erratic PD behavior. To understand the process of surface discharge an equivalent circuit model is developed, and its influencing material parameters such as the volumetric and surface electrical conductivities and the relative permittivity are measured experimentally. This paper describes the methodology and setup of the measurement based on international standards. The final goal is to provide the constituent model parameters that can describe the surface discharge model under DC stress.