Long - Term Behavior of XLPE Insulated Cable Models

A test cycle with electrical, thermal and combined stresses has been performed on models of XLPE insulated: cables in order to characterize this type of cable from the viewpoint of endurance to combined stresses. For this purpose the method of Combined Analysis of experimental data has been used, thus permitting the goal to be reached in less than two years. The experimenrtal methods and theoretical procedures are illustrated in the paper and the results shown by means of the three basic graphs for combined stresses. The material Under test has shown good endurance : values; of electrical and thermal threshold high enough to provide a reference for operating stresses. Some values for the stresses applicable in service are suggested.