A New 132,000-Volt Cable Joint

This paper describes what is believed to be a new form of high-voltage joint. The main novelties in the joint are that the metallic union of the conductors is insulated by wrapping on a single sheet of wide, impregnated paper by machine. The ends of the cable insulation are cut into a series of steps, or a taper, and knives on the machine cut the wide sheet of paper exactly to fit the steps or taper as the wide paper is being applied, until a smooth cylinder is built up to the original diameter of cable insulation. At this moment, the knives are removed, and at each end of the wide piece of paper, strips of tinfoil which have previously been cemented to the paper appear, and these strips gradually taper inward so that as the wide paper is applied, a flaring cone of metal is formed in the body of the insulation itself. This metallic cone acts as an electrostatic screen to control the longitudinal and radial stresses. It is formed automatically without any attention on the part of the splicer in the field, and it insures that all the insulation under stress is solid laminate paper insulation of the highest quality and breakdown strength, especially in the regions where the diameter is enlarged from that of the cable sheath to that of the joint sleeve. Test results are given.