Current-Limiting Characteristics of a Variable Resistive Type SFCL with Different Branch Lengths

With the ability of fast and automatically response between zero resistance and current-limiting resistance, resistive type superconducting fault current limiter (R-SFCL) is considered a valid way to solve the excessive fault current in short circuit. But seconds recovery time is acquired for a R-SFCL to return superconductivity after quenching. A variable resistive type SFCL (VR-SFCL) has been proposed to achieve fast recovery after quenching. In this paper, to design the superconducting tape length in VR-SFCL, a VR-SFCL model in AC 10 kV/630 A system was built, and the influence of the main coil and limiting coil lengths on the current-limiting characteristics was investigated. From the simulation results of VR-SFCL, the main coil and limiting coil length can be designed through the demands of recovery and withstanding, separately. To achieve recovery in 300 ms and safety of superconducting tape, the length of the main coil and limiting coil should be longer than 235 m and 150 m, which can decrease the length of VR-SFCL by 59.9% compared with R-SFCL.