Combined effects of fiber structure, coating and coupling methods on the fiber-optic quench response in HTS CORC cables

Abstract To enhance distributed optical fiber quench detection capabilities in high temperature superconducting (HTS) Conductor on Round Core (CORC) cables, the combined influence of fiber structure, coating material and thermal coupling method is systematically investigated in this paper. A heat transfer model linking Rayleigh backscattering spectral shift with response time is established based on optical frequency domain reflectometry. Three experimental factors, coating, coupling method and fiber structure, are evaluated on a liquid nitrogen test platform. An epoxy-impregnated, acrylate-coated bend-insensitive fiber improves the signal-to-noise ratio by 38 % and shortens the response time by 200 ms relative to a free bare fiber. These results offer practical insights for the selection of optical fiber types and coupling configurations for improving fiber-optic quench detection performance in CORC cables.