Calculation and analysis of leakage magnetic field and short-circuit impedance in split-winding transformer

In this paper, the leakage magnetic field and short-circuit impedance model of split-winding transformer is established. The 2D and 3D leakage magnetic field are analyzed, and calculate through short-circuit impedance and split parallel branch current distribution in different working conditions based on the field-circuit coupling method. Effectiveness of the proposed model is verified by comparison between experiment, analysis and simulation value. The results show that the 3D analysis method is a better approach to calculate the short-circuit impedance, so its analytical value is more closer to the experimental value compared with the 2D analysis results; the finite element method calculation error is less than 2%, while the leakage flux method maximum error is 7.2%; compared with the leakage flux method, finite element method can accurately calculate the leakage magnetic field and split branch current distribution. Then some reference bases are provided for accurate calculation short-circuit impedance and split parallel branch current distribution in split-winding transformer.