An analogy for estimation of dielectric and mechanical strength of insulators at elevated temperature

Various types of insulators working at elevated temperatures provide combination of dielectric and mechanical strength. Based on kinetic nature of strength and nonlinear “stress-strain” dependency of solids, the paper presents an analytical analogy between electrical and mechanical strength as a function of temperature to bridge the gap between fundamental principles and the practical needs. In this study, in particular, polyimide films and polymer concrete insulators are used to describe the “strength-temperature” relationship and predict corresponding values of breakdown voltage. It is shown also the analogy between electrical and mechanical coefficients which determine the influence of structure, rate of loading on dielectric or mechanical strength of insulators. Obtained results are promising for predicting dielectric strength and time-to-failure of insulators by using their properties only at room temperature according to existing standards or experimental data.