Multi-objective co-optimization of the guide vane closure law and rotor inertia in pumped-storage power system

Improving the transition safety and stability of pumped-storage hydropower plants supports the penetration of intermittent renewable energy into the grid. This paper presents the multi-objective optimization of the guide vane closure law and rotor inertia to reduce the rotational speed, water hammer pressure, and draft-tube vacuum by adopting genetic algorithms and a one-dimensional method of characteristic during load rejection transients. To reduce the increase in rotational speed to indirectly suppress pressure pulsations, a co-optimization of the guide vane closure law and rotor inertia is proposed. Results suggest that the above-mentioned co-optimization scheme can significantly reduce the increase in the rotational speed, water hammer pressure, and draft-tube vacuum and suppress the influence of pressure pulsations on the extreme pressure heads at the volute inlet and draft-tube inlet. Additionally, it can significantly reduce the transformation number of operation modes during pump-turbine load rejection transients.