Comparison of aging behavior of two-layer polymeric dielectrics aged at AC and DC voltages

In this paper, accelerated aging tests are conducted on samples of two-layer solid polymeric dielectric insulation. The aging behavior at AC and DC aging voltages are studied. The statistical distribution of time-to-breakdown, with confidence intervals, are represented using Weibull distributions. It was found that the statistical behavior of the time-to-breakdown of samples aged at AC voltages follows mixed Weibull distribution. On the other hand, DC aging study shows that the failure of the samples was basically dominated by one failure mode. The study also shows that the AC voltage-time characteristics is characterized by different life constants and threshold voltage.