Length compensation termination for low temp. cable - has looped conductor at room temp. which lies flat with extended retaining collars at operating temp.

摘要

A line building out of compensating termination network is for an electrical power cable in the form of a super-conducting wire wound in a spiral formation around an insulating former. The pitch angle 0 of the winding is related to the cable axis by 'arc sin square root k' and is not greater than 25 deg., where k is the expansion coefficient of the wire winding related to strength member insulator. (The figure represents the unit at two temps.:-the right hand side of the axis A is at low temp., 4K, the left hand side at room temp., 300K.) A cable section (2) comprises superconducting wires (5) in spiral formation around the strength member centre (3). Around the superconductors (5) are bandage wrappings (6, 7) with perforations to allow contact of the cooling agent with the superconductors (5). The expansion compensating termination (8) comprises a metal strip (12) of superconductor which forms a loop (16) at room temperature and flattens against the cable (11) at a 4K working temp. The fixing rings (17, 18) for the metal strip are compressed at room temp. but extend along the termination at working temp.