Combination of thermal and electromechanical breakdown mechanisms to analyze the dielectric breakdown in polyethylene terephthalate

Abstract

As an extension of the previous work on numerical analysis of electrical breakdown in polyethylene terephthalate films using electromechanical and thermal breakdown theories separately, an attempt is now made to combine these two models by introducing into the heat balance equation, variations in sample thickness which depend on Young’s modulus. Results of calculations have shown that although this model has improved the explanation of the observed negative temperature dependence and the positive pressure dependence of the experimental electrical breakdown field investigated at temperatures of 35, 70, and 100 °C under hydrostatic pressure ranging from 50 to 500 bar, a difference still remained between experimental and theoretical results. This could be attributed to other effects such as the space charge, which had to be neglected in this analysis to avoid complications.