Calculation and Measurement of Transport AC Loss of Re BCO CORC Cables for Electric Aircraft

This paper investigates transport AC loss in CORC cables for the ground-based demonstrator ASCEND at Airbus, which studies the feasibility of a superconducting powertrain for electric aircraft. The demonstrator includes a three-phase AC link consisting of three parallel cables operating at 500 Hz and 2350 A peak current. The transport AC loss of the three-phase cable is estimated using a 2D model assuming equal current in all tapes. The model predicts an AC loss of 40 W at 77.5 K and 0.4 W at 65 K. A second model is proposed, which computes the current distribution between the tapes in a single cable using mutual inductance matrices for helical tape conductors. This model predicts that, at 500 Hz, the outer two layers of a CORC cable carry a disproportionate fraction of the current. This will lead to additional AC loss if the critical current in the outer layers is exceeded. AC transport loss was measured on single CORC cables. Both models significantly underestimate the measured loss. Also, a frequency-dependent quench current below the DC critical current was observed at 48 Hz and 96 Hz.