Insulation characterization in multistress conditions by accelerated life tests: An application to XLPE and EPR for high voltage cables

This paper focuses on accelerated testing procedures that can be applied to XLPE and EPR for high voltage cables and that are aimed to achieve the thermo-electrical endurance characterization of insulation. Several methods and techniques for single and combined thermo-electrical stress are illustrated; indices for the evaluation of electrical, thermal, and multi-stress endurance are reported and their derivation is shown. Indications on the feasibility of the design-stress inference from tests on laboratory specimens also are given. Experimental results mainly refer to cable models, but data relevant to full-sized cables, as well as to simple, flat specimens, are also considered.