A Computational Approach for Modeling Partial Discharge Inception in Air Insulation Systems

Simulation software for estimating the basic inception characteristics of air and surface discharges, namely inception voltage and electric field, is presented. The simulation software, called CSPDI, utilizes an electrostatic solver using the Boundary Element Method and integrates physical modeling of partial discharge inception, based on the growth of an equivalent electron avalanche, together with advanced numerical methods. Simulation results are validated against experimental results obtained for short gaps in air alone and bridged by an insulating surface. A very good agreement is shown to exist between computed and measured values of inception voltage, especially with decreasing gap length and for negative discharges.