Analysis of the superconducting cable transposition in low resistance CICC joint

In an integrated structure low resistance CICC joint, current is conducted by outer cable strands coming into touch with the conductive Cu sole. So it is an important condition for satisfying joint performance that each strand of the cable inside the joint is able to come to the outermost by transposition. The author presents analysis, calculation and figures for the strand transposition. According to the twist procedures of the superconducting cable, the author computed the actual pitch of each stage cable, consecutively computed the projection of each stage cable on the axis of the cable (z axis) and the corresponding twist angle as the z coordinate changes, which is then drawn by Auto CAD. From the results shown in the figures, the minimal cable length, which enables each strand to transpose almost equally to the outermost of the cable in such a length, can be determined as the optimal joint length