Inter-strand circulating current analysis of end-region transposed coil of power generator using 3D multi-layer FEM

Stator coils of large rotating machines are divided into strands which are transposed to reduce the inter-strand circulating current loss. To evaluate the effect of transposition, circulating current analysis is required but full 3D analysis is difficult because of the complicated configuration of the transposed coils. In this paper, magnetic field analysis model using 3D multi-layer finite element method is proposed to calculate the inter-strand circulating current in the stator coil with transposition in the coil end region especially with non-transposed region. Then circulating currents are analyzed considering the magnetic flux in the end region and some transposition patterns are compared.