Pumped Storage Plants (PSP) using reversible pump-turbines offer the possibility to store large amounts of energy with high efficiency and at reasonable cost. For reversible high head pump-turbines, the characteristic curves exhibit an S-shape in the turbine, turbine break and reverse pump quadrants. This S-shape leads to unstable behavior of the turbine when coupling to the grid (for small guide vane opening) or to surge transient phenomena in case of emergency shutdown (for large guide vane opening).

Pumped Storage Plants (PSP) using reversible pump-turbines offer the possibility to store large amounts of energy with high efficiency and at reasonable cost. For reversible high head pump-turbines, the characteristic curves exhibit an S-shape in the turbine, turbine break and reverse pump quadrants. This S-shape leads to unstable behavior of the turbine when coupling to the grid (for small guide vane opening) or to surge transient phenomena in case of emergency shutdown (for large guide vane opening).