High temperature superconducting (HTS) systems, and in particular superconducting magnets (SCMs), developed and deployed by the Department of Defense are necessary to maintain and advance the U.S. naval defense program. Tremendous advantages in utilizing HTS SCM technology have been impeded, however, by the inability to reliably monitor and protect the magnets against the occurrence of a quench. A quench in a SCM is a fault condition whereby the magnet rapidly transitions from the superconducting to normal state with the dissipation of the stored magnetic energy. If a quench results in a significant fraction of the stored energy being deposited locally within the superconductor, that region of superconductor (and thus SCM) is likely to be destroyed. At present, HTS SCMs rely on voltage-based methods of detection for ensuring prevention and protection against quench placing them at high risk for damage and complete failure. Here, Rayleigh-backscattering Interrogated Optical Fibers (RIOF) with the capability for accurate and rapid detection of changes in temperature and strain as a function of location, with mm spatial resolution over 100s of meters in length for HTS is proposed. The focus addresses remaining RIOF challenges by specifically addressing the needs of SCMs in the solicitation from the Navy.
Benefit: Quench detection/protection is a key remaining impediment to the implementation of superconducting magnet systems using high temperature superconductors for defense, energy, transportation and medical systems. The development of a quench detection technique based on Rayleigh-scattering interrogated optical fibers (RIOF) is emerging, however, with direct applicability to DC and AC applications. The strengths of RIOF are its inherent immunity to electromagnetic noise and sensitivity to very smaller perturbations (including those that do not increase the local temperature above the current sharing temperature) in a truly distributed sensor with excellent temporal and spatial resolutions. RIOF offers the potential to not only provide remarkably sensitive quench detection, but also the ability to monitor the overall health of the magnet.
Keywords: AC HTS magnets applications, AC HTS magnets applications, Quench Prevention, High temperature superconductor, Quench Detection, High-field Magnets, Rayleigh Interrogated Optical Fibers, Quench Protection
