Characterization of the electrical resistance of high temperature superconductor coated conductors at high currents using ultra-fast regulated current pulses

Abstract

This paper focuses on the experimental determination of the electrical resistance (R) of commercial high temperature superconductor (HTS) coated conductors (CCs) at currents well above the critical current. The major novelty of this work rests on the unique experimental capability of applying constant current pulses in the sample (up to 1000 A) for durations as short as 15 μs, which allows very precise control of the amount of energy dissipated in the sample (the Joule effect), as well as the resulting temperature rise. By varying the applied current and the duration of the pulses, we show that we can achieve a relatively accurate characterization of R(I, T ) simply from the measured dynamical V -I characteristics of the CCs. The resistance model obtained in this way is very important, as R(I, T ) is the most fundamental design parameter in many practical HTS applications, especially in fault current limiters.

Evaluation of the Applicability of Phenomenological HTS Models for Numerical Analysis of Quenches in Coated Conductors: Simulations vs. Experiments

“…For this work, the temperature dependence of the empirical-laws-exponent as well as the effect of the interface resistance [8] and of the electrical contact with the substrate may change the electrical behaviors of the simulated tapes [9]. From the obtained results, it seems that the applicability of the temperature-dependent phenomenological laws are questionable and also that further research on the materials properties, such as the one initiated by Sirois et al [10], have to be done to simulate accurately the behavior of coated conductors during quenches.…”

Investigation of Power Dissipation Mechanisms in Coated Conductors at High Current Densities Based on Ultra-Fast Pulsed Current Measurements

“…The system could generate square current pulses up to 1000 A, with a rise time as short as 3-10 . Experimental details and the procedure used to extract the electric field at zero temperature rise from the measurements can be found in [6].…”

“…The power dissipated in the superconductor therefore takes the form (5) where is the surface density of the moving vortices. In [9] it was established that, as a general rule, the vortex density in a film carrying current can be written as (6) where is the flux quantum. In our case, we must take into account that the current flowing in the shunt of thickness results in a magnetic field that contributes to the vortex density and that, for , no vortex is in the flow regime.…”

“…The Manuscript [3]), but not that of the intrinsic physical processes occurring in the superconducting films and in the metallic layers. Shorter pulses durations are required for this purpose [4]- [6].…”

“…By extrapolating properly the measured voltages, these conditions have allowed us to estimate the voltage corresponding to the current injected in the samples discarding thermal effects [6]. We have studied the behavior of two CCs from the same manufacturer, but protected with different metallic layers.…”