ELECTRIC CABLE COVERED WITH FOAMED WATER-BARRIER SEMICONDUCTING LAYER Russian patent published in 2003 - IPC

FIELD: power transmission or distribution cables for carrying intermediate- or high-voltage currents. SUBSTANCE: cable is covered with metal sheath and foamed water-barrier semiconducting layer. This layer performs three main functions, as follows: (1) flexible and at the same time uniform suppression of radial expansion forces and reduced number of cable covering layers as result of heat cycles occurring in the course of cable operation thereby preventing deformation and fracture of metal sheath; (2) maintenance of electric circuit continuity between cable core and metal sheath; (3) effective shielding against ingress and spreading of moisture and/or water over cable core that may occur, for example, due to probable fractures in metal sheath. Third function is afforded due to inclusion of water-swelling material in foamed layer. EFFECT: enhanced operating reliability of cable. 29 cl, 1 tbl