Quench Detection Criteria for YBa2Cu3O7‐δ Coils Monitored via a Distributed Temperature Sensor for 77 K Cases

Quench recovery time of an optical fiber encapsulated resistance-type DC superconducting fault current limiter coil determined by a Raman-based distributed temperature sensing system

“…Recently, distributed optical fiber sensing technology has been introduced into quench detection due to the advantages of optical fiber sensors such as strong anti-interference, high insulation, flexible installation, etc [14][15][16][17][18][19][20][21][22][23]. In distributed optical fiber sensing systems, light pulses are injected into a measuring fiber at equal time intervals to induce scattering lights in the fiber.…”

“…By demodulating the amplitude or frequency of the backscattering lights, the variations of environmental physical parameters such as temperature and strain can be obtained, and the spatial information corresponding to these variations also can be presented by calculating the return time or frequency domain information of the backscattering lights. According to scattering light types and demodulation principles, the most common distributed optical fiber sensors for quench detection are the Raman-based distributed temperature sensing system (Rm-DTS) [14][15][16], Rayleigh based optical frequency domain reflectometer [17][18][19][20][21][22] and Brillouin based optical frequency domain analysis [23]. These sensors have their own advantages, but for engineering application, Rm-DTS is one of the most promising quench detection systems because of its long measuring distance, simple and reliable system, low cost, and insensitivity to stress.…”