A study on mitigation method of perpendicular magnetic field in HTS superconducting coils for power transformer

Methods to mitigate a perpendicular magnetic field component on the surface of a high temperature superconducting (HTS) tape in HTS coils by arranging low current density (LCD) coils in the edges were studied analytically. Four types of winding arrangement with and without the LCD coils at both edges of the superconducting winding, which are used to model a three-phase 40 MVA HTS transformer, were proposed. The results of magnetic field analysis in the proposed winding arrangements reveal that (1) the maximum perpendicular magnetic field (B_⊥max) on the surface of the HTS tape is influenced markedly by the LCD coils arrangements and that (2) the winding arrangement which is LCD coils installed in both edges of top and bottom in the LV and the HV winding is very effective in reducing the B_⊥max in both edges of top and bottom.