Influence of Electric Shield Materials on Temperature Distribution in the End Region of a Large Water-Hydrogen-Hydrogen-Cooled Turbogenerator

To investigate the influence of different electric shield materials on the temperature distribution in the turbogenerator end region, a 330-MW water-hydrogen-hydrogen-cooled turbogenerator is considered in this paper. Mathematical and physical models of the three-dimensional (3-D) transient electromagnetic field in the turbogenerator end region are established. The magnetic density distribution and the losses of end parts are obtained with different electric shield materials. The loss values obtained from the 3-D transient electromagnetic field calculations with different electric shield materials are applied to the end parts as heat sources. Pressure and fluid velocity values from flow network calculations are applied to the end region as boundary conditions for the fluid and thermal coupling analysis. In addition, a 3-D fluid and thermal coupling model of the turbogenerator end region is established. The distributions of the surface heat transfer coefficient on the inner and outer surfaces of the electric shield are determined with different electric shield materials. Temperature distributions of the stator-end copper winding, finger plate, clamping plate, and electric shield in the turbogenerator end region are investigated with different electric shield materials. The calculated temperature results for the electric shield are compared with measured values, and the calculated results agree well with the measured values.