The Influence of Transposition Angle on 3-D Global Domain Magnetic Field of Stator Bar in Water-Cooled Turbo-Generator

Reasonable transposition structure of stator bars in water-cooled turbo-generators could reduce circulating current of strands, and related factors on distribution change of circulating current are complex and diverse. Transposition angle is one of the most important influencing factors, and its influencing degree on circulating current is still unclear. A 600 MW water-cooled turbo-generator is set as an example, a 3-D physical model of transposition bars in a single slot is established, and a field-circuit coupling method is used in 3-D numerical calculation. The optimization of transposition angle is researched, and the distribution changes of 3-D global domain magnetic field, maximum current, and circulating current loss in different transposition angles are obtained. Finally, the calculation results are compared with that of the improved analytical algorithm to validate the accuracy of the solving model.