The Statistical Analysis of a High Voltage Endurance Test on an Epoxy

Abstract

This paper is concerned with the accelerated aging of solid insulating materials, as a means of estimating their service lives and identifying superior dielectrics. The assumed failure mechanism is electric treeing. A constant-stress accelerated aging experiment on a transparent epoxy at three voltage levels is described. All factors thought to be important in the electric treeing mechanism were rigidly n-controlled, and the inception and growth intervals were measured separately. The results indicate that the times to inception and failure are three-parameter Weibull distributed, whereas the growth period may be either Lognormal or three-parameter Weibull distributed. The Inverse Power Law could not be n-confirmed. There was little correlation between the inception and growth intervals. Statistical analysis showed that there is much uncertainty in these results, and this is true for most published accelerated aging tests done to date. The general applicability of accelerated aging tests is questioned.