Evaluation on Current Limiting Properties During 3-Phase Connection Between the Wires for SFCL and HTS Cable

Advantages of YBCO thin film type wires are as follows. First, their high critical current density allows effective handling of normal and fault currents. Second, high index values can lead to fast fault current limiting because of the rapid build-up of resistance. Third, a variety of stabilizing materials can be employed in YBCO thin film type wire, resulting in more flexible adjustment of limiting resistance after the quench. In this study, the wires for the current limiter and cable were selected through an over-current conducting (transport) test that took into account the characteristics of the YBCO thin film type wire. The current limiting characteristics of the wires for the current limiter and cable according to the fault type and fault angle were examined. The tests were conducted in three phases, and the fault type and fault angle were examined for single-line-to-ground fault, double-line-to-ground fault and triple-line-to-ground fault at the fault point of R-phase 0 that was defined as the fault standard in the test. The YBCO thin film type wire for the current limiter with a critical current of 80 A_rms, critical temperature of 90 K and voltage rating of 0.6 V_rms/cm had stainless steel stabilization layer, while the Bi-2223Ag wire for HTS cable with a critical current of 110 A_rms, critical temperature of 106 K and voltage rating of 2.5 V_rms/cm had silver stabilization layer. The required lengths were determined considering the voltage rating of wires, and the wires were respectively wound on a straight former and a spiral former.