Effect of Electric Field on PD Activityand Damage into Solid Dielectric Materials

In this paper, the effect of applied electric field on the damagedue to partial discharges activity into the surroundings dielectrics of a narrow channel encapsulated within the volume of a dielectric materialis evaluated using a kinetic model based on Particle in Cell - Monte Carlo Collision (PIC-MCC) model. After application of an electric field across a dielectric material which contains a narrow channel,repeated ionization processstarts in the gaseous medium of narrow channel. Charged particles, especially electrons, gain energy from the electric field across narrow channel and cause damage into dielectric surfaces of narrow channel on impact. The dependence of the electron energy distribution function (EEDF) on the applied electric field is studied. It isseen that, during PD activity within narrow channel,the damage to the surrounding dielectrics and consequently the surface conductivity increases. These estimationsare performed based on the number of C-H bond-scissions produced by the impacting electrons of a single PD pulse. Based on this technique, the consequent damage into the solid dielectric and the time required to increase surface conductivity is computed. The formation of acid molecules due to interaction of PD pulse with polymer surface in presence of air and humidity causes changes in the surface conductivity of the surrounding dielectrics of the narrow channels.