Numerical analysis of the AC losses of 500-m HTS power cable in Super-ACE project

Abstract

The alternating current (AC) losses of 500-m high- T C superconducting (HTS) power cable in Super-ACE project are calculated by using an electric-circuit model. The cable core is consisted of a former (copper-stranded wire conductor), HTS conductor (Ag/Bi-2223 tapes, 1 layer), electrical insulation (LN 2-impregnated laminated paper), HTS shield (Ag/Bi-2223 tapes, 1 layer) and protection (copper-braided wire). Numerically calculated AC loss (the total loss) is obtained by a sum of the self-field loss and external-field loss (hysteresis losses) consumed at the HTS conductor and HTS shield, the ohmic loss caused by a resistance of copper of the former and protection, and the eddy-current loss caused by an axial field at the former. The calculations are compared with experimental results measured by a calorimetric method. The calculations are almost equal to the measurements at wide transport-current range. At transporting 1 kA rms to the cable, the calculation indicates that the total loss of 1.29 W m −1 (the measurement is 1.3 W m −1) is obtained by a sum of 0.89 W m −1 as the self-field loss, 0.32 W m −1 as the external-field loss, 0.06 W m −1 as the ohmic loss and 0.02 W m −1 as the eddy-current loss. On the other hand, Central Research Institute of Electric Power Industry (CRIEPI) has estimated that the AC loss is obtained by a sum of 0.5 W m −1 consumed at the HTS conductor and HTS shield as the hysteresis loss, and 0.8 W m −1 consumed at the former as the eddy-current loss. The author’s result contradicts CRIEPI’s estimation. It is considered that the difference is caused by an overestimation of the axial field at the former in CRIEPI’s loss calculation.