Rapid Hot-Spot Detection Based on Weak Reflection Point and Phase Demodulation OFDR

Quenching protection is one of the key challenges for the operation of high-temperature superconductor (HTS) magnets, and optical frequency domain reflection (OFDR) technology has great application potential in quenching detection of HTS due to its high spatial resolution, fast response, anti-electromagnetic interference, and other characteristics. In this article, we monitored the temperature change process of the simulated HTS device by combining the optical fiber weak reflection point and phase demodulation OFDR technology, and finally achieved the measurement of the temperature as low as about 80 K and the measurement accuracy of 0.001 °C (at room temperature). Experiments have shown that OFDR distributed temperature measurement system has a faster response time than traditional point-type electrical temperature sensors due to its ability to monitor temperature changes along the HTS line in real-time without waiting for heat to propagate on the copper tube, which enables early warning of quench events.