Combined electronic and thermal breakdown Models for polyethylene and polymer laminates

A comprehensive DC dielectric breakdown model has been extended for polyethylene in which specific time and voltage regimes were identified for thermal and electrical failure modes. In addition to electron injection processes, space-charge formation and the associated electric field distribution are critical in determining the conditions for insulator failure. Space charge formation and distribution are governed by electron and hole injection from the electrode as well as charge mobility and trapping. Breakdown fields of 5 MV/cm are predicted through a computational model for polyethylene films in the 5 to 200 µm thickness range and there is weak dependence of breakdown field on thickness. The model is applied to predict the effect of interfaces for multilayer polymer structures that act as barriers.