Breakdown mechanism of the charged solid dielectric during short circuit discharge

Abstract

The phenomenon of PET (polyethylene terephthalate) breakdown during short circuit discharge is studied. A theoretical model for detrapping by collisional ionization is proposed for interpretation of the breakdown mechanism. The coefficient for detrapping by collisional ionization and the relation between it and the velocity of the discharging are obtained. A critical electric field of the short circuit breakdown by space charges due to collisional ionization by detrapping is also suggested for solid dielectrics, and confirmed experimentally. The critical field is directly proportional to the thickness of the dielectric and inversely proportional to the detrapping coefficient of the collisional ionization, the time constant of the discharging circuit, and the dielectric constant.<>