Calculation of stray losses in continuously transposed conductor cable transformer windings by multi-slice methodology

In this paper, the calculation of stray losses distribution in core type transformer windings with continuously transposed conductor (CTC) cable based on multi-slice methodology is presented. Particular attention has been paid to hot spots due to the distribution of stray current losses on each individual winding conductor of CTC cable. As an alternative to the commonly adopted invariable distribution of current on each conductor cross-section around the winding turns, this paper proposes detailed calculation of the current (direct, eddy and circulating) and how the conductor transposition influences the distribution of stray losses. A practical example shows how application of the proposed methodology becomes especially useful when evaluating loss concentration under short circuit between individual conductors within the CTC cable. Multi-slice numerical results are also compared to 3D FEM data.