Development of new 500 kV laminated paper insulated self-contained oil-filled cable and its accessories

The development of a self-contained 500 kV oil-filled cable that is insulated with a cellulose-paper/plastic-film/cellulose paper laminate, and its accessories, is described. The dielectric loss of this cable has been confirmed to be about one-third that of conventional kraft paper cable. By reducing the insulation thickness to 25 mm, rather than the 33 mm used for conventional cables, the cable has been made very compact. This was possible because of the high dielectric strength of the laminate. As a result, the shipping reel length of the proposed cable, which is about 10% lighter in total weight and 10% smaller in overall diameter than conventional cables, can be greatly increased. The reliability and the stability of the cable have been demonstrated in a 1-1/2-yr field test