GB308349A - Improvements in high tension electric cables - Google Patents

Abstract

308,349. Felten & Guilleaume Carlswerk Akt.-Ges. March 22, 1928, [Convention date]. Conduits and casings; cables with conductive shields.-An underground cable for very high voltages comprises a copper conductor a surrounded by insulation b which preferably consists of paper layers impregnated with oil and resins. Conducting pressure-equalizing layers g may be inserted in the insulation b which is surrounded by a metal, for instance lead, sheath c. The cable thus formed is held by distance pieces f in a tube d, over which a metallic wire braiding e may be placed. The tube d may be of hard paper, porcelain, glazed earthenware, or of metal such as iron, the wire braiding e being omitted when a metal tube d is used. The space h between the cable and the tube sides may be filled with oil or air which may be under pressure, or with non-rigid insulating material. A voltage mav be imposed on the metal sheath c, and, if desired, on the insertions g, so as to alter the voltage gradient across the inner layers of the insertions g, by tapping from a transformer t, as shown in Fig. 1.