Thermal Modeling and Experimental Validation in the Rotor Region of Hydrogenerator With Different Rotor Structures

Thermal management is often considered a bottleneck in the pursuit of the next generation hydrogenerator in the electric power system. Overheating of the complex rotor parts has become one of the main problems affecting safe and stable hydrogenerator operation. In this paper, a 250 MW hydrogenerator is analyzed. The transient electromagnetic field of the hydrogenerator is calculated and the losses of the rotor parts are obtained. The rotation of the hydrogenerator rotor is considered. Three-dimensional fluid and thermal mathematic and physical models of the hydrogenerator are established. The loss values from electromagnetic field calculations are applied to the rotor parts as heat sources in the temperature field. After solving the fluid and thermal equations of fluid-solid conjugated heat transfer, influence of the structures of rotor support plate, rotor pole body insulation, and rotor excitation winding on the fluid flow and temperature distribution in the rotor region of hydrogenerator is studied using the finite volume method. The calculated temperature result of rotor excitation winding is compared with the measured value. The calculated temperature result agrees well with the measured value. It provides an important reference for optimizing the rotor structure of the larger hydrogenerator.