The current distribution in a striated YBCO tape subjected to both a magnetization and a transport current

Abstract

In this work we have quantified the results concerning the current distribution and the values of the full magnetization current If during a complete cycle of an externally applied magnetic field, Bext. A YBa2Cu3O7−x-coated conductor in the form of a striated tape 12 mm wide and 100 mm long, with unstriated ends, was exposed to a gradually changing external magnetic field. For every selected phase of the initial cycle of the magnetic field (first cycle after cool-down), the perpendicular component of the self-field profile over the center of the tape was measured. The Tikhonov method of regularization was used in the inverse calculation of the current distribution. For every quarter of the cycle the magnetization current distribution profiles corresponding to different levels of gradually changing external magnetic field Bext were plotted. After finishing the whole cycle, the external magnetic field was eliminated upon returning to a zero level and the gradual ramping of a transport current was commenced. The change in current distribution because of the increasing transport current took place only in the non-saturated half-width of the tape current profile.

Finite-element simulations of field and current distributions in multifilamentary superconducting films

“…We used a model for computing the current and field distributions in multifilamentary superconducting thin films subjected to the simultaneous effects of a transport ac current and a perpendicularly applied dc field. In the finite-element simulations, the geometry and the value of the parameters were chosen to allow a direct comparison of the calculated magnetic flux and the current profiles with experimental data obtained by time-resolved magneto-optical imaging (TRMOI) [8], scanning Hall probe [9] and Hall probe arrays [10]. A comparison would provide both a test for the model itself as well as new information on the complex behavior of these systems, as we demonstrated in previous TRMOI studies on HTS single bridged thin films [11].…”

Superconducting technology for overcurrent limiting in a 25 kA current injection system

“…Each of these parameters is very dependent on the other two properties present. Maintaining the superconducting state requires that both the magnetic field and the current density, as well as the temperature, remain below the critical values, all of which depend on the material [13].…”

“…The design was refurbished completely with a state-ofthe-art distinctive circuit controlling the overcurrent of a 25 kA CIT system higher than the nominal current, based on a fluxlock-type SCLD. Another advantage of the proposed circuit is the exposure of an HTS element to the magnetic field created by the CIT busbars that can dramatically speed up the limiting resistance and consequently the protection of the system [13,19]. The calculation of the HTS parameters for overcurrent limiting is also performed to suit the required current levels of the CIT.…”