Effect of winding transposition structure on the distribution of transverse leakage magnetic field

Winding transposition structures are commonly built into transformers to suppress winding circulation and minimize loss. They alter the distribution of the transverse leakage magnetic field and electromagnetic force. Researchers have not yet considered the winding transposition structures when investigating the transverse leakage magnetic field distribution. The relative position of conductors in a transposition structure is analyzed in this paper, and a scale model experiment is conducted to verify the effect of the structure. In the meantime, a finite element method model which includes the winding transposition structure of the scale models is established and verified by comparison with experimental observations. Then, the distribution of the transverse leakage magnetic field and the axial electromagnetic force of the 110 kV transformer under rated tapping are obtained. The transverse leakage magnetic field and axial electromagnetic force in the low-voltage winding are affected by the transposition structure, while the high-voltage winding is not affected. Compared with models without transposition structure, the amplitude of the axial electromagnetic force linear density of the 40th winding disk under rated tapping increases from a value close to zero to 25 N/m. The transposition structure needs to be considered when calculating the electromagnetic force and winding mechanical characteristics.