Dielectric strength and voltage life of polyethylene

AMONG the most promising types of material for insulating high-voltage cables are those in the polyethylene family. Since its introduction around 1940, polyethylene has been used successfully for submarine telegraph and telephone cable, for high-frequency coaxial communication cable, and for multiconductor control cables. It has also been used, in increasing quantities, for high-voltage cable. Its application in 5,000-volt circuits has been accepted by the Insulated Power Cable Engineers Association for some time, and present IPCEA ratings extend to 15,000 volts. There are appreciable amounts of 15,000-volt polyethylene-insulated power cable in use, both in this country and in Europe. Beyond this, there are scattered installations for systems up to 34,500 volts, and manufacturers expect to push the limits even higher.