Effect of the sheath resistivity and tape geometry on eddy current loss in Bi(2223) tapes

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For describing the E-J relation of high-Tc superconductors (HTS) in power applications, where the applied current I is generally limited by Ic, the critical state model, a piecewise linear generalization, or a simple power-law of the type E=Ec(J/Jc)^n are most often used. The power-law cannot be used for modelling the E-J relation with I>>I_c due to the unbound exponential increase of the electric field for currents above Ic, while in reality the non-linear HTS resistivity is limited by its normal state val

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The finite element method has been employed in order to simulate the behaviour of a HTS cable for transport current applications. The E-J model includes an anisotropic dependence of the critical current density Jc and power index n on the local magnetic field, whose magnitude is non-negligible and determines the effective critical current of the cable. The cable consists of four electrically insulated layers, each of them composed by 20 superconducting tapes, providing a total critical current of about 4 kA

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The nonlinear behavior of High Temperature Superconductors (HTS) is often modeled by an E-J power law in order to describe their electromagnetic properties. This paper presents AC loss calculations in HTS tapes, performed by means of FEM commercial software using the A-V method. The implemented nonlinear model of the HTS tapes takes into account the B-dependence of the critical current density Jc and the power index n. The expressions for Jc(B) and n(B) are obtained from electrical measurements of a Bi-2223

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Effect of the sheath resistivity and tape geometry on eddy current loss in Bi(2223) tapes

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