Development of CORC cables for helium gas cooled power transmission and fault current limiting applications

High-temperature superconducting (HTS) direct current (dc) power cables allow high levels of power transmission and distribution at low loss and can be tailored to effectively limit fault currents. HTS Conductor on Round Core (CORC ) power transmission cables offer additional benefits over other HTS cable designs, including a much higher current density and a higher degree of flexibility. These benefits make CORC cables most suitable for applications in confined spaces where tight bends are required, such as onboard naval ships and in data centers. The development of CORC power transmission cables for operation in pressurized helium gas is described, including their ability to act as fault current limiting cables. The 10 m long bipolar dc CORC power transmission cable system is designed to operate at a current of 4000 A per pole at 50 K in pressurized helium gas. The test results at temperatures between 60 K-74 K in helium gas at a pressure of 1.7 MPa are described both during normal operation and during an overcurrent event. The results demonstrate the potential of CORC cables to operate at currents exceeding 10 000 A per pole at 50 K at current densities of more than 200 A mm−2, resulting in the most energy dense superconducting power transmission cable to date. The successful operation during an overcurrent event also shows the added benefits of the high level of current sharing between tapes in CORC cables that allow them to be operated as FCL cables without the need to incorporate a substantial amount of stabilizer. The successful test is a major milestone towards reliable high energy density power transmission in helium gas cooled superconducting power systems based on CORC cables.