Tests of Parallel Connected HTS 2G Tapes for Fault Current Limiters

Abstract

The superconducting fault current limiters at high voltage levels and for high current applications should be constructed with modular structure. The superconductor tapes have to be connected in series according to voltage condition and in parallel in order to increase the nominal current of the devices. The process of quenching may occur in all superconducting devices, but in fault current limiters this process must be fully controlled. Uncontrolled transition of the superconducting tape from the superconducting state to the resistive state may cause local overheating and burning through of the high-temperature superconducting tape and, consequently, lead to the destruction of the entire superconducting device. The knowledge about these phenomena in order to be able to properly design superconducting fault current limiters is indispensable. In this study, fault currents were applied to the parallel-connected YBCO tapes in a liquid nitrogen bath, and the characteristics of the current distribution were examined experimentally. The tests were carried out for 2G high-temperature superconducting tapes with copper stabilizer and on tapes without the copper stabilizer.