Temperature- and field-dependent characterization of a conductor on round core cable

Abstract

The Conductor on Round Core (CORC) cable is one of the major high temperature superconductor cable concepts combining scalability, flexibility, mechanical strength, ease of fabrication and high current density; making it a possible candidate as conductor for large, high field magnets. To simulate the boundary conditions of such magnets as well as the temperature dependence of Conductor on Round Core cables a 1.16 m long sample consisting of 15, 4 mm wide SuperPower RE BCO tapes was characterized using the "FBI" (force -fieldcurrent) superconductor test facility of the Institute for Technical Physics (ITEP) of the Karlsruhe Institute of Technology (KIT). In a five step investigation, the CORC cable's performance was determined at different transverse mechanical loads, magnetic background fields and temperatures as well as its response to swift current changes. In the first step, the sample's 77 K, self-field current was measured in a liquid nitrogen bath. In the second step, the temperature dependence was measured at self-field condition and compared with extrapolated single tape data. In the third step, the magnetic background field was repeatedly cycled while measuring the current carrying capabilities to determine the impact of transverse Lorentz forces on the CORC cable sample's performance. In the fourth step, the sample's current carrying capabilities were measured at different background fields (2 -12 T) and surface temperatures (4.2 -51.5 K). Through finite element method (FEM) simulations, the surface temperatures are converted into average sample temperatures and the gained field-and temperature dependence is compared with extrapolated single tape data. In the fifth step, the response of the CORC cable sample to rapid current changes (8.3 kA s −1 ) was observed with a fast data acquisition system. During these tests, the sample performance remains constant, no degradation is observed. The sample's measured current carrying capabilities correlate to those of single tapes assuming field-and temperature dependence as published by the manufacturer.

Measurement and Numerical Evaluation of AC Losses in a ReBCO Roebel Cable at 4.5 K

“…To get better understanding of the magnetization and thermal stability, a three-dimensional time dependent thermalelectric network model of coated conductor cable structures is developed. The model is capable of simulating Roebel, CoRC [14] and Stacked (twisted) type of cables.…”

‘Defect-irrelevant’ behavior of a no-insulation pancake coil wound with REBCO tapes containing multiple defects

“…REBCO (RE-Ba 2 -Cu 3 -O x , RE: rare Earth) coated conductor has been regarded as one of the most viable high-temperature superconductor (HTS) options for next-generation high field magnets, mainly owing to its large in-field current carrying capacity and mechanical robustness. Commercial REBCO tapes show a 95% critical current (I c ) retention strain of 0.5% or higher, which corresponds to a tensile stress of 550-850MPa depending on the tape's architecture [1][2][3][4][5][6][7][8].…”

Investigation of Mechanical Strains in Thermal Compensation Loop of Superconducting NbTi Cable during Bending and Cyclic Operation

“…It was found that the critical current drops significantly at the strain of 0.6%. The effect of axial strain on the critical current in a high-temperature superconductor for electric power application was studied in [ 30 ]. It was presented that the strain 0.33% significantly limits the critical current.…”