A stability verification technique using acoustic emission for an HTS monofilar component for a superconducting fault current limiter

This paper reports an acoustic emission (AE) technique that was developed for detecting the quenching and stability characteristics of high-temperature superconductors (HTSs), particularly a BSCCO-2212 monofilar component for a resistive superconducting fault current limiter (SFCL) system. The 24kV class SFCL, which was recently developed by the KEPRI-LSIS collaboration group in Korea, requires almost 150 BSCCO-2212 monofilar components. A BSCCO-2212 monofilar HTS undergoes thermal and mechanical stress creating microcracks during and after quenching or reaching a fault state such as during a short-circuit test. The AE technique is a useful tool for detecting the presence of transient heating and the existence of hot spots within the superconducting fault current component.