Next generation electric power systems require higher capacity, efficiency, and stability to meet the demands of increasingly complicated grid systems. High-temperature superconducting (HTS) Conductor on Round Core (CORC®) power transmission cables provide unique solutions by offering high operating currents and current densities in a very small cable cross-section, which can also include the ability to protect electric power apparatus by serving as a fault current limiting (FCL) cable.
Advanced Conductor Technologies is developing 2-pole dc transmission cables, cable terminations, and connectors to be cooled with pressurized cryogenic helium gas for shipboard use. The development and successful test results of a 10-meter long, 2-pole dc CORC® power transmission cable, rated at 4,000 A per phase, will be discussed. The development includes CORC® feeder cables that form the connection between the room-temperature bus bar and the CORC® power transmission cable located inside the helium gas environment.
In addition, the inherent FCL capabilities of a short kA-class CORC® wire of less than 4 mm thickness are demonstrated in liquid nitrogen, developing nearly instantaneous voltages in excess of 20 V/m that increased to about 70 V/m within 15 ms of applied overcurrents up to 250 % of the critical current. Enhanced current sharing between tapes enabled by the CORC® cable topology appears to mitigate the issue of hot-spots caused by inhomogeneities on the HTS tape level by providing several alternate superconducting routes for current to bypass low Ic sections of the tapes. Operation of the CORC® FCL conductor in stand-alone operation and operated as part of a hybrid-cable system, in which the overcurrent is redirected to a normal conducting path outside of the cryogenic environment, are demonstrated without any degradation of the CORC® wire performance.