Weekly-scale optimized complementary scheduling for a provincial power grid supplied by multiple cooperative pumped-storage power plants

Power grids with high renewable energy penetration face the challenges of flexible resource shortages and multi-energy optimization. This study develops a weekly-scale multi-objective optimization framework for provincial grid hybrid systems combining hydro, wind, photovoltaic, thermal, nuclear, and pumped-storage power. A zonal-hierarchical solution strategy effectively reduces the computational complexity of provincial-level multi-energy coordination, while the high-dimensional optimization of multiple pumped-storage power plants is addressed through a decoupled discrete-continuous decision-making process. This approach provides a systematic way to capture inter-day energy transfer mechanisms. A case study on a Chinese provincial grid demonstrated the framework's effectiveness in enhancing the system's flexibility and regulation capabilities, reducing residual load fluctuation by 16.74–67.96% and decreasing thermal power peak shaving depth by 14.69–68.86%, while increasing clean energy generation by 0.77–4.33%. Regarding the pumped-storage plants, optimized operation showed that unit-level scheduling outperformed plant-level scheduling, and the actual-to-planned ratio strategy was the most effective. Notably, the contribution of pumped-storage power plants to mitigating residual load fluctuation was as high as 73.78%, with weekly-regulated pumped-storage power plant playing a crucial role in balancing fluctuations across days. This study offers new insights into flexible resource scheduling to support large-scale renewable integration and sustainable power systems.