Search

Leakage magnetic fields in high temperature superconducting (HTS) transformer windings reduce the critical current and increase the ac losses in HTS tapes. Moreover, because of the anisotropic properties of the HTS tapes, the influence of the radial component of the leakage field on critical current and ac losses is much stronger than that of the axial one. For these reasons, leakage magnetic fields must be carefully considered in HTS transformer design. In this paper, we report a study of the influence of the core structure and the winding configuration on the leakage field by the finite-element method (FEM), and offer some suggestions for reducing the maximal radial component of leakage field to make the HTS transformer more efficient. [ABSTRACT FROM AUTHOR]

In a high-temperature superconducting (HTS) transformer leakage magnetic field, especially its radial component, decreases the critical current and increases the ac losses in the tapes. Because of zero resistance of HTS tapes a slight unbalance among the branch inductances of the windings may result in heavy circulating current, however, an accurate calculation of it must depend on the magnetic field analysis. Thus, a numerical analysis of the leakage magnetic field is especially necessary for an HTS transformer design. In this paper the leakage magnetic field of several transformer geometries is studied by finite element method, and based on it, the circulating current distribution is calculated. Some suggestions for improving the leakage field and circulating current distribution are presented to make HTS transformers more efficient. [ABSTRACT FROM AUTHOR]