Multi-Stage Current Leads for Superconducting Power Transmission Cables

Legacy power distribution cables will not be able to meet the future requirements of Navy electric ships. While power distribution systems employing high temperature superconductors (HTS) have the potential to meet this need, further development work is required to improve the performance and increase the technology readiness level of key system components. The proposed work focuses on the current leads used to connect the cryogenic HTS cables to ambient temperature generators and loads. For ship-scale transmission currents and transmission lengths, the thermal loads due to the current leads dominate the system cooling requirements to the extent that a system with a single-stage conduction-cooled current lead would have higher losses than the equivalent copper cable. Careful optimization of both the current lead and the cryocooler is required to reduce the system power requirements. Creare and Massachusetts Institute of Technology (MIT) have teamed together to develop a multi-stage current lead designed on the basis of a system-level optimization to minimize the power required, size, weight, and cost of the HTS power transmission system. In Phase I, we will complete the optimization and design the current lead and cooling system. In Phase II, we will fabricate and test a prototype system.