We enhanced the performance of superconducting tapes during quenching by coating the tapes with various composites, with regards to the application of such coated systems in superconducting fault current limiters. In composition of the coating, we varied the type of epoxy matrix, the content of ceramic filler particles and the use of reinforcement in order to optimize the thermal and the mechanical stability of the coated tapes. By this way modified superconducting tapes were able to reduce the maximum temperature 170 °C of not modified superconducting tape to 55 °C during the quench with electric field up to 130 V m−1.

The wind and react (W&R) coil of inner diameter 53 mm has been made of multi-core MgB2/Nb/CuNi wire manufactured by internal magnesium diffusion (IMD) process. W&R coil is wound of not insulated rectangular wire of 1 mm2with only 5 µm thick stainless steel foil used for interlayer insulation. Transport current performance of the coil and short wire samples were measured in liquid He bath at external magnetic fields 4.5-8.5 T and also in self-field conditions inside the sub-cooled water ice at temperatures between 33 K and 38 K. The presented MgB2 coil exhibits stable behavior at water ice cooling and its high space factor allows to reach high current density of winding in comparison to the data of already published MgB2 coils. Presented results demonstrate that MgB2 windings can be used safely at He-free conditions inside the sub cooled water ice, and this technique can be further optimised and used for future MgB2 coils.