Increase of the annual energy output in hydraulic powerplants through active flow control

Traditionally, hydraulic powerplants have been strongly contributing to energy generation. At present, with the expanding participation of other non-storable renewable energy sources in the electrical market composition, water turbines can importantly contribute to the electrical grid stability and to energy storage. With the increasing demand for such services, new procedures have to be developed, in order to allow the hydraulic turbines to operate in critical load conditions, as part load, for example. The technique proposed here, based on pitching guide vanes, was numerically tested with instationary CFD models and delivered possibly promising results, concerning the machine performance and stability, at part load conditions. The extension of the operating range of hydraulic powerplants, through the turbine active flow control, yields even greater flexibility to them in providing regulation services to the electrical grid. This technique has also the potential to extend the operational life of main turbine components and may lead to the increase of the annual energy output in some cases.