Self-consistent Modeling of the $I_c$ of HTS Devices: How Accurate do Models Really Need to Be?

Abstract

Numerical models for computing the effective critical current of devices made of HTS tapes require the knowledge of the Jc(B,theta) dependence, i.e. of the way the critical current density Jc depends on the magnetic flux density B and its orientation theta with respect to the tape. In this paper we present a numerical model based on the critical state with angular field dependence of Jc to extract the Jc(B,theta) relation from experimental data. The model takes into account the self-field created by the tape, which gives an important contribution when the field applied in the experiments is low. The same model can also be used to compute the effective critical current of devices composed of electromagnetically interacting tapes. Three examples are considered here: two differently current rated Roebel cables composed of REBCO coated conductors and a power cable prototype composed of Bi-2223 tapes. The critical currents computed with the numerical model show good agreement with the measured ones. The simulations reveal also that several parameter sets in the Jc(B,theta) give an equally good representation of the experimental characterization of the tapes and that the measured Ic values of cables are subjected to the influence of experimental conditions, such as Ic degradation due to the manufacturing and assembling process and non-uniformity of the tape properties. These two aspects make the determination of a very precise Jc(B,theta) expression probably unnecessary, as long as that expression is able to reproduce the main features of the angular dependence. The easiness of use of this model, which can be straightforwardly implemented in finite-element programs able to solve static electromagnetic problems, is very attractive both for researchers and devices manufactures who want to characterize superconducting tapes and calculate the effective critical current of superconducting devices.

References in corpus (3)

• Strongly Enhanced Current Densities in Superconducting Coated Conductors of YBa2Cu3O7-x + BaZrO3
• Calculation of AC losses in stacks and coils made of second generation high temperature superconducting tapes for large scale applications
• Self-field Effects and AC Losses in Pancake Coils Assembled from Coated Conductor Roebel Cables

Cited by in corpus (15)

• Superconducting Magnetic Bearings Simulation using an H-formulation Finite Element Model
• Numerical models for AC loss calculation in large-scale applications of HTS coated conductors
• A self-consistent model for estimating the critical current of superconducting devices
• Potential and limits of numerical modelling for supporting the development of HTS devices
• A parameter-free method to extract the superconductor's $J_c(B,\theta )$ field-dependence from in-field current-voltage characteristics of HTS tapes
• Investigation of AC Loss in HTS Cross-Conductor Cables for Electrical Power Transmission
• Simulation of Stacks of High Temperature Superconducting Coated Conductors Magnetized by Pulsed Field Magnetization Using Controlled Magnetic Density Distribution Coils
• Modeling and simulation of termination resistances in superconducting cables
• Simulation and experiments of Stacks of High Temperature Superconducting Coated Conductors Magnetized by Pulsed Field Magnetization with Multi-Pulse Technique
• Open Source Codes for Computing the Critical Current of Superconducting Devices
• 3-D Numerical Simulations of Twisted Stacked Tape Cables
• DC Characterization of a Circular, Epoxy-Impregnated High Temperature Superconducting (HTS) Coil
• New Experimental Method for Investigating AC-losses in Concentric HTS Power Cables
• Estimation of maximum possible trapped field in superconducting permanent magnets in 2D and 3D
• Estimation of Self-Field Critical Current and Transport-Magnetization AC Losses of Roebel Cables