Comparison of Overcurrent Responses of 2G HTS Tapes

In this paper, the comparison of transient responses of second-generation (2G) high-temperature superconducting (HTS) tapes under alternating overcurrent was presented. The authors performed the series of measurements of the SF4050 and SCS4050 HTS tapes produced by Superpower Co. The measurements were carried out for various amplitudes of current exceeding a critical value given by the manufacturer (I
_c
= 100 A, dc, @77 K, self-field). Seven measuring probes were soldered to each tape, which allow for simultaneous recording of the supplying current and voltage in each test segment. Tapes were immersed in liquid nitrogen bath under atmospheric pressure and supplied from the 50-Hz voltage source with adjustable amplitude. Numerical models of SF4050 and SCS4050 tapes were build using PSPICE environment. The models assume the nonlinear dependence of tape parameters in the function of temperature and the variable cooling conditions during transient state. The numerical results were compared with the measurements, and good correlation was achieved. Elaborated models allow for the calculation of the overcurrent responses of 2G HTS tapes with and without copper shunts.