Fast Hotspot Detection in SFCLs by Exploiting Strain Response in Optical Fiber Sensing

Superconducting fault current limiters (SFCLs) can be used to limit currents in both meshed DC and AC grids by transitioning from superconducting resistive state, the presence of high currents. While device is theoretically a great way protect grids, inherent inhomogeneity critical along superconductor length lead localized heating, called hotspots, ultimately destruction SFCL device. At EPFL under European Union project Fastgrid, an extremely efficient Mach-Zehnder interferometer (MZI) based optical fiber sensing technique has been developed patented that detect even singular hotspots within 15 ms SFCLs. The MZI response characterized strain sensitive as well temperature contribution. This paper outlines investigation means FEM modeling into sensitivity. A 2-D thermal model tape was made study transfer REBCO tape. simulation results showed rise observed slower than time, proving experiment measurements. Sound mechanical coupling between enhance hence reduce hotspot detection time. With this improved performance, health monitoring for SFCLs much more reliable.