Cable life predictions from breakdown and accelerated aging tests: influence of frequency and high fields

We have shown elsewhere that our model of dry electrical aging of extruded cables describes very well accelerated aging of XLPE cables performed at constant temperature and frequency. The model, without any adjustable constant, is based on two basic parameters: the activation energy and volume. The main objective of this paper is to show that frequency and high fields affect significantly the value of the activation volume. The influence of these aging parameters on the impulse and AC breakdown fields of actual XLPE cables are discussed. From a practical point of view, this means that the aging characteristics at constant temperature and frequency of a given cable might be predicted from fast breakdown tests performed under at least three different voltage raise ramps.