Accelerated aging of XLPE and EPR cable insulations in wet conditions

The aim of this paper is to present the investigation results of the influence of wet service conditions of cross-linked polyethylene (XLPE) and ethylene-propylene with rubber based formulation (EPR) cables on water absorption of XLPE and EPR cable insulations. Also, this paper describes the effect of accelerated aging of XLPE and EPR cable insulations in wet conditions on electrical characteristics. The experimental set up was assembled for the following XLPE and EPR cable insulations: steam and dry cured with water tree retardant crosslinked polyethylene (TR-XLPE) and steam cured EPR. During tests, tap water was injected (1) into the cable conductor with cable ends closed and (2) into the cable conductor with cable ends opened. The XLPE and EPR cable insulations together with the water present in the cable were subjected to electrical stress and heating. The results were analyzed by mathematical modeling based on Fick's law.