Statistical Consideration of Dielectric Breakdown of Polymeric Insulating Material

To study the statistical behavior of dielectric breakdown of polymeric materials, experiments were conducted using a parallel plate electrode system for two polymeric insulating materials: low-density polyethylene (LDPE) and polyethylene terephthalate (PET). The results of the experiment were analyzed applying the Weibull distribution function. Values of median breakdown strength (BDS), shape and location parameters of Weibull distribution function were evaluated to elucidate the dielectric breakdown of both materials. The results underscore the great difference in breakdown strengths of LDPE and PET. The number and size of impurities included in both materials was examined to judge their influence on the breakdown strength. Based on statistical analyses of experimental results, the impurities´ influence on dielectric breakdown of polymeric materials was discussed.