Future power systems on board Navy ships require electrical power in the order of 10s to 100s MW, which cant be provided by conventional copper or aluminum power cables. The Navy has been developing high-temperature superconducting (HTS) cables for shipboard power transmission applications as a potential solution in which the required power can be transported in a lightweight and low-loss system. Initially, HTS cables developed by the Navy were several inches in thickness, not including the cryostat. Their size decreased substantially with the introduction of HTS Conductor on Round Core (CORC) by Advanced Conductor Technologies (ACT). CORC cables of 7 mm thickness demonstrated their ability to carry a current of 4.5 kA when cooled with helium gas to 65 K in 2018. Current ratings above 10 kA at 50 K in CORC cables of less than 8 mm thickness are readily achievable. Several technical challenges remain in the development of compact HTS cable systems based on CORC cables. Compact terminations that integrate 2-pole dc, or 3-phase ac CORC cables with current leads that connect them to a room temperature bus bar, while providing means to cool the current lead with helium gas, need to be developed. Such current interfaces rated between 1 and 4 kA need to be reliable, practical and economical, while at the same time provide the CORC cable system with voltage ratings up to 450 V ac and 12 kV dc. Advanced Conductor Technologies, together with the Center for Advanced Power Systems (CAPS) will develop compact cable termination and current lead interfaces for ac and dc CORC power cables, rated between 1 and 4 kA per pole. The designs will include integration with 2-pole twisted pair and co-axial, as well as 3-phase twisted and tri-axial CORC cables. The interfaces will include compact and efficient helium gas heat exchangers, while their designs will aim at the smallest possible footprint and weight while also developing voltage ratings of at least 450 V ac and 12 kV dc. Power cable system components, such as the cryogenic interface and coolant flow loops that would allow helium gas to be injected into and extracted from the same end of the cable system, will also be developed. The proposed program will leverage the vast experience of CORC power cable development for Navy applications of Advanced Conductor Technologies and the helium gas cooling infrastructure and high-voltage testing capabilities of CAPS.
Benefit: Superconducting power cables that have compact current interfaces with integrated heat exchangers will provide the Navy with practical and reliable power cables that are capable of transmitting power as high as 48 MW in a cables system of less than 2 inches in diameter. Such power cables allow compact and efficient power delivery to high-power applications that the Navy is considering for implementation on future ships, such as high-power radar and rail guns. Several potential commercial markets for superconducting power cables with compact current interfaces exist. The next generation of data centers will operate at such powers that can't be delivered with conventional copper and aluminum cables, and require compact superconducting cable systems. High-current power cables are also being considered for use in offshore windmill farms and as interconnects between the windmill farms and the shore. The technology being developed within this program thus has many potential applications within the Navy and with commercial customers.
Keywords: Superconducting Power Cables, Superconducting Power Cables, helium gas cooling, helium gas cooled current leads, compact cable terminations, CORC power cable, 48 MW power rating
