Electron beam processing of power cable insulation

Abstract

The advent of electron beam (EB) accelerators capable of delivering high beam powers (⩾ 100kW) at voltages in the range of 2–5 MV, implies the basic suitability of such equipments for the cross-linking of power cable insulation. As compared with the familiar process of electron beam (EB) processing of wire and cable for specialty applications, this potential application involves relatively great insulation thicknesses and great rigidity of the conductor/insulation system. An irradiation method designed to overcome the latter limitation (which restricts severely the usefulness of the conventional multi-pass method of irradiation) must also meet the criteria of adequate accelerator voltage, and dose uniformity. In addition, other potential problems related to the insulation thickness, and the requirement to handle the cable at speeds corresponding with the capabilities of the accelerators, must also be overcome. These questions are discussed as related to power cable irradiation projects in Japan, Europe and the U.S., and proposed solutions are evaluated. It would appear that the rotation method at least, and possibly certain magnetic beam-handling methods as well as multiple-irradiator methods, can provide acceptable solutions to the problems, for power cables designed for operating voltages to at least 35 kV, possibly 69 kV.