Study on leakage magnetic field and magnetic field shielding for transformers

Abstract

This paper deals with the leakage magnetic field calculation and magnetic field shielding design of transformers. A large-capacity traction transformer is firstly established, and its magnetic flux density and eddy current loss of the transformer tank are calculated by the layered subdivision method and the surface impedance method. To reduce the eddy current loss of the tank, plate-shaped magnetic shielding and electromagnetic shielding are installed on the surface of the tank. And the simulation results show that plate-shaped magnetic shielding has better shielding effectiveness compared with electromagnetic shielding. Then based on the plate-shaped magnetic shielding, the tile-shaped magnetic shielding is proposed to further reduce the magnetic flux density and loss of the tank. By analyzing the shielding effect of tile-shaped shielding at different heights and widths, the tile-shaped shielding structure with the best shielding effect is obtained. Finally, the advantages of tile-shaped shielding are verified by magnetic-thermal coupling analysis.