Electrical aging and breakdown of crosslinked polyethylene cables

A model of dry AC electrical aging of extruded cables is described. The model is based on two basic parameters, the activation energy ΔG and volume ΔV and there is no adjustable constant. It is shown that it agrees very well with experimental data for XLPE cables aged under constant temperature. It is also shown that the impulse and the AC breakdown fields for at least two different set of results can be directly related to the basic parameters deduced from electrical aging tests performed on the same samples. From a practical point of view, this means that the breakdown strength of a XLPE cable can be deduced from long time aging data. Conversely, the aging characteristics could be predicted from at least three breakdown measurements lasting some seconds and performed under three different voltage raise rates.