In WP3, the Power Take-Off (PTO) and machine-side control are studied and designed. In the past year, good progress has been made on both subjects.
For the shaft-driven Contra-Rotating Reversible Pump-Turbine (CR RPT), many possible PTO configurations are possible. These configurations were compared based on their influence on RPT and electric machine performance, as well as machine component loads and lifetime. Finally, a PTO design with coaxial contra-rotating shafts, where the electrical machines are housed in a bulb, was deemed most appropriate. It has, among other benefits, minimal impact on flow uniformity and RPT efficiency. For the machine-side control, conceptual control algorithms have been studied based on the initial CR RPT design from WP2. In these algorithms, the two propeller speeds and the inlet vanes angle are controlled to reach a certain power setpoint, which is based on the grid state and can vary from – 10 MW (pump mode) to +10 MW (turbine mode).
Since there are three control parameters, the chosen power setpoint can be reached with additional constraints, such as optimal efficiency and minimal mechanical stresses.
MSc. Daan Truijen