Abstract
The superconducting field winding of 70 MW class high response excitation superconducting generator requires the maximum operation current of 4.5 kA at the field of 6 T and needs to allow the field change of 10 T/s. Besides these, superconductors have to meet the requirement of saddle shape winding in the slot of the rotor and require the mechanical strength withstanding the centrifugal force as well as electromagnetic force.
The developed conductor has the configuration of double stranded cable, consisted of NbTi, Cu and CuNi. An optimization was made, taking into account the requirement of low AC loss and high current density. The critical current of 13.6 kA was achieved at the field of 6 T and the AC loss was 6.9 kW/m3, small enough for the aim of 10 kW/m3. The developed low loss high current density superconductor will be able to be applied to the field winding of 70 MW class high response excitation superconducting generator.
