Thermal fatigue and aging properties of water-impervious cable

On-core water impervious power cable has a water-impervious layer consisting of lead foil and a semiconducting plastic film. This layer is thermally bounded to the insulation shield of the cable core and prevents ingress of water to its interior. According to this design, the water-impervious layer is subjected to thermal expansion and contraction directly from the core and, as a result, thermal fatigue properties assume greater importance. Factors such as strain in the water-impervious layer, aging behavior of the lead foil, heat cycle behavior on the cable, and high-temperature behavior of composite tapes were investigated. Based on these results, it is estimated that the life of the on-core water-impervious layer is approximately 40 yrs