Test of Maximum Endurable Quenching Voltage of YBCO-Coated Conductors for Resistive Superconducting Fault Current Limiter

Abstract

Voltage tolerance during quench is one of the most important parameters for YBCO-coated conductors, especially for resistive type superconducting fault current limiter (SFCL) applications. How much voltage can be sustained per unit length of YBCO tape when experiencing fault current indicates the total required amount of the tapes to construct a resistive SFCL. In this paper, a step-down transformer is used to provide the short-current. As the voltage of the secondary side is not continuously variable, we change the voltage per unit length of the YBCO tape by varying the length of the tape. And the effect of the duration of short-current is also considered. A series of test have been performed to determine the maximum voltage drop that each YBCO tape can stand at fault current. The V-t curve has been measured after the tape experiencing successive quenches. Through a large number of experiments we will acquire the maximum endurable quenching voltage per unit length of YBCO tapes when experiencing short-current for different durations. The results presented in this paper would provide useful information for optimizing the design of a resistive SFCL.