Calculation and analysis of 3-D nonlinear eddy current field and structure losses in transformer

Magnetic leakage field and eddy current loss in tank, yoke clamps and other electrically conductive construction parts of transformer are computed by three-dimensional (3-D) nonlinear time harmonic finite element method (FEM). Core and tank material magnetizing characteristics were treated as nonlinear by using nonlinear B (H) curve. On this basis, distributions of eddy current losses in the construction parts are analyzed. The magnetic shields that added to tank wall and yoke clamps were used to reduce the eddy current losses in tank wall and yoke clamps of power transformer and the effect of different types of shields were discussed. Then some reference bases are provided for design of transformer.