Thermal Mapping of the Hydrogenerator’s Reactive Power Boosting Ability at Various Time Windows

In the future, bulk power generation facilities like large hydropower plants need to be utilized more flexibly and provide extended services over shorter time intervals. This work presents a comprehensive thermal mapping for the stator’s iron yoke, the stator copper, and the rotor copper of a large hydrogenerator. The whole capability diagram has been investigated to depict the physical thermal limits for providing overexcited reactive power augmentation. Two different operational modes have been defined, i.e., the boosting and the emergency mode, which apply for $120^{\circ}\mathrm{C}$ and $155^{\circ}\mathrm{C}$, respectively. Moreover, the loss and thermal modeling utilized a physics-informed neural network parameter estimation technique to obtain the different maps for various time windows. Finally, a sensitivity analysis is done to show the machine temperature variance with respect to the water inlet temperature and consider a voltage-collapsed power grid.