Influence of Different Power Factors and Slips on End Temperature Rise of Variable Speed Pumped Storage Machine

Relative to the traditional pumped storage machines, the variable speed pumped storage machine (VSPSM) has strong frequency and voltage regulation capabilities by the AC excitation. However, the enhancement of the regulation capability also leads to the increment of the temperature rise. For the purpose of investigating the temperature variation in the end zone of the VSPSM, a 336-MVA VSPSM is chosen as the research reference in this article. The electromagnetic-fluid-thermal coupled heat transfer calculation model in the end zone of the VSPSM is constructed. The flux density and loss distribution in the end zone of the VSPSM are calculated under different power factors and slips. The losses of the stator end parts are less influenced by the slip compared to the rotor end parts, which are more affected. The variations of temperature rise in the tooth plate, end core, clamping plate and the rotor retaining ring are revealed along with the power factor and slip. It is found that the stator tooth plate is the end part with the peak temperature. This research is able to lay a theoretical basis for optimising and designing the end structure of the VSPSM.