Investigation On Dynamic Thermal Characteristics Of HTS Cable During Short-circuit

High-temperature superconducting (HTS) cable is suitable for transferring power with large capacity and high current density, low losses and friendship environment. The short-circuit fault accident of the cable is inevitable during its operation, the dynamic stability is then one of important characteristics. In this text, two 2.2-m long cold dielectric (CD) model conductors were fabricated by YBCO coated conductors (YBCO CC). The short-circuit test was performed with current 25 kA durations of 2 s in liquid nitrogen (LN2) temperature of 77.3 K. The temperature rise and recovery of cable conductors were simultaneously measured during the fault test. Additionally, the temperature rise and recovery were simulated during and after fault accident, respectively. The experimental results are agreement with the simulated results, After the short circuit test, the critical current of HTS cable was retested, there is no degradation, which shows that the design of the cable is reasonable. The results can provide important reference for design and operation of the practical HTS cable.Three-phase tri-axial superconducting cable is a new type of superconducting cable. Compared with single phase superconducting cable, three-phase tri-axial superconducting cable has obvious advantages, for example, the number of superconducting tape is half and AC loss is smaller without stray magnetic field. In addition, since the functions of three-phase coaxial superconducting cable are same with three separate single-phase cables by using one former, it only needs a common cryogenic vessel and thus takes up less space. The design parameters of tri-axial cable, including number of superconducting tape, winding angle and thickness of insulation was performed based on single phase superconducting cable. The magnetic field of the cable can be determined by numerical simulation, and the AC loss can be then calculated by using Bean model. Counterflow cooling is economic for short cable, while counterflow cooling with secondary cooling station suitable for longer cable. Temperature distribution at rated current offers initial value to the simulation of temperature distribution when fault occurs, temperature rise would not exceed limited level when fault current was limited to 2 times rated current.