Energy cable having a crosslinked electrically insulating layer, and method for extracting crosslinking by-products therefrom

The present invention relates to an energy cable comprising at least one cable core comprising an electric conductor, a crosslinked electrically insulating layer, and zeolite particles placed in the cable core. The zeolite particles are able to extract and absorb, very efficiently and irreversibly, the by-products deriving from the cross-linking reaction, so as to avoid space charge accumulation in the insulating material during cable lifespan. Moreover, the present invention relates to a method for extracting crosslinking by-products from a cross-linked electrically insulating layer of an energy cable core, which comprises manufacturing the energy cable core comprising zeolite particles, heating the energy cable core up to a temperature causing migration of the crosslinking by-products from the crosslinked electrically insulating layer; and then placing a metal screen around the energy cable core. The zeolite particles substantially irreversibly absorb some of the crosslinking by- products during the heating step, while a fraction of crosslinking by-products which is gaseous at ambient temperature, such as methane, or which has a low boiling point,is eliminated by causing it to diffuse out of the cable core.