Design of a termination for a high temperature superconducting power cable

A cable conductor consisting of superconducting tapes wound onto a tight flexible tube (former) is placed inside a thermally insulating jacket (cryostat). This assembly is electrically insulated with an extruded polymer dielectric kept at room temperature. Cooling is provided by a flow of liquid nitrogen inside the former. The purpose of an end termination is to connect the superconducting cable conductor at cryogenic temperature to an electrical wire at room temperature and an external cooling machine at ground potential. Here we describe the design and construction of such an end termination. Aspects considered in the design include the thermal insulation of the termination, the transition from superconducting tapes to a normal conductor, the current lead carrying current between high and low temperatures, the transfer of liquid nitrogen over a high voltage drop and that of providing a well defined atmosphere inside the termination and around the cable conductor.