Demonstration of kA-Class Rutherford Cables Using MgB2 Wires for an Energy Storage Device Suitable for a Liquid Hydrogen Indirect Cooling

Superconducting Magnetic Energy Storage (SMES) has been a promising option amongst potential other storage devices to support world-wide demands for introducing more renewables into the utility grid. If MgB
₂
strands are used for SMES, liquid hydrogen, one of the renewables, could be used not only as a clean energy source but also as a coolant for the superconducting device. For large-scale coil design, mechanically fragile multi-filament strands should be used for their low AC loss feature considering that the transport current inside the coil would be always changing. To realize such a design, we designed and fabricated the large current capacity for AC-use Rutherford cable, together with experimental tests for its feasibility assessment. Based on the latest test results and development of commercial MgB
₂
strands with high mechanical strength, and this research and development of kA-class cable at liquid helium temperature for extrapolating the critical current (
I_c
) at hydrogen temperature, we believe this approach has the potential to make a practical SMES device with MJ capacity. In this paper, the world's largest-capacity AC cable design and test results including critical current evaluation under several background field strengths are shown, and the stability and current re-distribution are also discussed.