Chenxi Li

The massive grid integration of renewable energy necessitates frequent and rapid response of hydropower output, which has brought enormous challenges to the hydropower operation and new opportunities for hydropower development. To investigate feasible solutions for complementary systems to cope with the energy transition in the context of the constantly changing role of the hydropower plant and the rapid evolution of wind and solar power, the short-term coordinated scheduling model is developed for the wind–solar–hydro hybrid pumped storage (WSHPS) system with peak shaving operation. The effects of different reservoir inflow conditions, different wind and solar power forecast output, and installed capacity of pumping station on the performance of WSHPS system are analyzed. The results show that compared with the wind–solar–hydro hybrid (WSH) system, the total power generation of the WSHPS system in the dry, normal, and wet year increased by 10.69%, 11.40%, and 11.27% respectively. The solar curtailment decreased by 68.97%, 61.61%, and 48.43%, respectively, and the wind curtailment decreased by 76.14%, 58.48%, and 50.91%, respectively. The high proportion of wind and solar energy connected to the grid in summer leads to large net load fluctuations and serious energy curtailment. The increase in the installed capacity of the pumping station will promote the consumption of wind and solar energy in the WSHPS system. The model proposed in this paper can improve the operational flexibility of hydropower station and promote the consumption of wind and solar energy, which provides a reference for the research of cascade hydropower energy storage system.

With large-scale grid-connected renewable energy, new power systems require more flexible and reliable energy storage power sources. Pumped storage stations play an important role in peak shaving, valley filling, and promoting renewable energy consumption. This paper presents the reasonable energy-abandonment operation of a combined power generation system (CPGS), in which a pumped storage station is the core control power, with an ultra-high proportion of renewable energy. Firstly, based on the seasonal characteristics of wind, solar, and load demand, typical days are selected through improved clustering analysis algorithms. Then, a daily optimal scheduling model for combined power generation systems (CPGS) is developed with the goals of economy, low-carbon, and stable operation. Finally, the correlation between the energy-abandonment rate and pumped storage station peak shaving and system optimization operation indicators is obtained by a reasonable energy-abandonment calculation method considering source-grid-load coordination. Taking the operation data of an energy base in the western region of China as an example, when the penetration rate of renewable energy is 60–70% in the future, the operating cost on the power side is greatly affected by the construction of the source side. When the system operates at a planned reasonable energy-abandonment rate of 2%, electricity regulation, load tracking, and daily operating costs all show better performance.

To analyze the influence mechanism of asymmetric erosion distribution characteristics in the injector of the Pelton turbine, a detailed analysis of erosion amount and distribution characteristics within different regions of the nozzle and needle is conducted, elucidating the motion and distribution characteristics of sediment particles. The Euler-Lagrange method is used to numerically calculate the flow process of sediment particles with a concentration of 2% and diameters of 0.1mm, 0.5mm, 0.75mm, 1mm, and 2mm in the injector, and the erosion amount is estimated. The results show that the sediment particle diameter significantly influences the symmetry of erosion distribution in the injector. When the diameter gradually increases, the symmetrical phenomenon gradually disappears. Furthermore, the influence of sediment particle diameter on erosion degree within different regions of the injector is inconsistent. With the increase of sediment particle diameter, the average erosion rate of the needle increases. While the average erosion rate in the guide plate area of the nozzle decreases at first and then increases, the nozzle throat is reversed. The guide plate affects the distribution and movement of sediment particles at its end, aggravating the asymmetric erosion phenomenon at the nozzle, especially on the small particle size sediment.