Operational degradation of HTS tape parameters used in SFCL and its impact on the coordination of power system protection

The article presents the results of experimental investigations on HTS tapes intended for the construction of superconducting fault current limiter (SFCL). The influence of repeated exiting of HTS tape from the superconducting state by the surge current to the stability of the critical current value for HTS 2G superconducting tape type CF has been checked. The influence of the amount of energy released during the tape shock with insulation and without electrical insulation on the stability of the tape parameters was investigated. The obtained results indicate that as a result of thermal and dynamic processes occurring during the operation of the limiter, the tape parameters may be degraded and the value of the critical current may decrease. Degradation of the tape and reduction of the critical current value may result in disturbed coordination of the power system protection (PSP) settings with the SFCL parameters. The influence of degradation of HTS tapes on the coordination of PSP settings was analyzed.