Analysis of leakage flux, losses, and temperature in large synchronous generator end zone under the multi-layer screen thickness based on novel iterative method

The multi-layer screen is the key component in the large synchronous generator end zone. The leakage flux, losses, and temperature of end components are significantly affected by the thickness of multi-layer screen in the synchronous generator. To investigate the influence of multi-layer screen thickness on the end leakage flux, losses, and temperature in the synchronous generator end zone, 1407MVA nuclear power synchronous generator is studied. Three-dimensional transient electromagnetic field model of synchronous generator end zone is established. Three-dimensional transient electromagnetic field in the end zone of 1407MVA synchronous generator with the multi-layer screen is calculated based on the novel iterative method. The flux density of end components is compared and studied in the end zone under the variation of multi-layer screen thickness. Influence of the different thicknesses of multi-layer screen on the losses of the shield plate, screen, finger plate, and stator end core is researched. The losses of end components obtained from 3D end electromagnetic field calculation are applied to the end zone as the heat source in the three-dimensional fluid and thermal coupled field. The temperature distribution of the end components is determined. The accuracy of the calculated results is validated by the experimental values.