Advanced Compact Shipboard High Temperature Superconducting (HTS) Cable Terminations

Future power systems on board Navy ships require electrical power in the order of 10’s to 100’s MW, which can’t 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.