Application of Epoxy-Bonded FBG Temperature Sensors for High-Temperature Superconductor-Coated Conductor Quench Detection

Fast detection of quench in high-temperature superconductors (HTS) is essential for the application of HTS magnets due to the low normal zone propagation velocity (NZPV). In this work, quench measurement of single-HTS wires has been carried out at 80 K through gas cooling. We use both electrical and thermoelectric methods to verify the ability of fiber Bragg grating (FBG) sensors to be applied to quench detection and study the quench behavior of HTS tape in the view of NZPV. An FBG chain with five FBG sensors was attached to a 12-mm-width Superpower REBCO tape in order to monitor the temperature during a quench induced by a bonded heater. PT100 sensors were also attached to the HTS tape as reference sensor. The measured FBG wavelength data was compared with the voltage and PT100 temperature data. Our results show that commercially available FBGs can capture the temperature change as soon as the quench occurs; however, further work is needed to improve the stability and accuracy of the sensors.