New Composite Insultation

New composite materials such as laminated tapes were applied to high voltage cables. Plastic films laminated with kraft papers were developed for the high voltage oil-filled cables to improve the dielectric properties. The 500 kV oil-filled cables insulated with these laminated papers were also developed and tested with good results. Lead foil, laminated with plastic film, was developed for the water-impervious layer of XLPE cable to improve its reliability. It was confirmed that bow-tie trees were observed in the conventional XLPE cable after six months of water-immersion, but the water impervious XLPE cable retained its original performance.