Analysis of Alternating Overcurrent Response of 2G HTS Tape for SFCL

The scope of this article was to find the transient response of the 2G high-temperature superconducting (HTS) tape under alternating overcurrent. The authors performed a series of measurements for the SF12050 HTS tape produced by SuperPower Inc. The tape was fed by a 50-Hz ac voltage source with adjustable amplitude. The temporal dependences of the tape current and voltage drops in each test segment were recorded simultaneously. The measurements were performed for the current amplitudes exceeding the critical value specified by the manufacturer ( I_c = 270 A @77 K, self-field). The instantaneous values of the tape temperature during overcurrent transient period were also determined. Additionally, the numerical analysis of the SF12050 tape was performed. A numerical model was built using PSPICE environment. The model assumes the nonlinear dependence of tape parameters in the function of temperature, as well as the variable cooling conditions during transient state. The constructed model was verified with measurement results.