Performance of 66-77-kV Cross-Linked Polyethylene Insulated Cable and New Developments

Significant problems of 66-77-kV cross-linked polyethylene insulated cable are discussed. Improvements in cable construction and manufacturing processes realized over the past five years are described as well as their influence on cable performance. Higher impulse and ac breakdown voltage and higher corona starting voltage can be obtained, and the allowable electrical stress for long service performance is expected to be raised by use of the extruded semiconductive layer for both conductor and insulated shielding, and by the technical developments of the tandem extrusion of two or three layers to ensure firm bonding among two semiconductive layers and insulation. Descriptions are also given of the construction and performance of the cable joint and termination ion which is set up by the irradiated polyethylene tape-wrapped, molded method, as well as the specially made double-layer self bonding tape-wrapped method.