Test results from the 200 kA SMES/ETM conductor

Abstract

The critical current and stability margin of a 200-kA, copper-stabilized, cable-in-conduit conductor cooled with helium-II have been measured. The test specimen was 3 m long, inserted in a uniform background dipole field of up to 5 T with an effective length of 0.9 m. The critical current of the conductor was measured at 1.8 K and found to be 280 kA at a total field of 5.8 T, 260 kA at 6.4 T, and 215 kA at 7.4 T. Normal zones of 2-cm initial length were initiated by inductive heaters, and the voltage and temperature of the conductor in the heated zone were monitored for recovery of propagation. The stability margin is reported as a function of the current density over the cable space at various background fields, bath temperatures, heated lengths, heater pulse durations, and numbers of cumulative load cycles. The test results demonstrated that the conductor can operate at 200 kA in the Engineering Test Model for SMES where the peak total field is 4.13 T.