A general model for life estimation of cables under DC stress with voltage-polarity inversions accounting for space-charge effects

This paper proposes a new model which provides the life estimation of polymeric insulation subjected to dc stress, with or without voltage reversals, on the basis of accelerated life tests carried out at constant dc stress and measurements of space charges. Accordingly, the performance of a new material under dc electrical stress can be characterised by short-term tests, so that, for example, the expected life of a cable can be evaluated once the rate of voltage reversals expected during its life has been guessed. The model is applied to results of tests carried out on polyethylene materials