Day-ahead scheduling for peak shaving incorporating intraday output adjustment of cascade hydropower stations under uncertainty in renewable energy forecast

The expanding penetration of solar and wind power introduces many problems to power grid operation owing to their intrinsic variability and intermittent nature, particularly in compounding peak shaving pressures. Cascade hydropower serves as a highly effective resource for peak shaving in power systems. An important problem in power system operation lies in how to scientifically make the day-ahead scheduling for cascade hydropower stations and guide their execution during intraday operation to meet peak shaving demands. This study develops a day-ahead peak shaving model for cascade hydropower that incorporates intraday output adjustment. A multi-period adjustment rule is defined to calculate the adjustment of hydropower output for each period in the intraday operation, according to the wind and solar energy forecast errors and adjustment coefficients. The hydropower output is adjusted based on the day-ahead generation schedule to minimize intraday residual load fluctuations. A day-ahead peak shaving model is developed based on the multi-period adjustment rule for the simultaneous optimization of the day-ahead generation schedule and the adjustment coefficients. This study employs a provincial-level power grid in southwestern China as the case example, and intraday operation is simulated under multiple typical wind and solar output scenarios. The simulation results demonstrate that the proposed peak shaving model can conduct peak shaving effectively, reducing the peak–valley difference of residual load by over 19.54% compared to the contrast model. This study presents a reliable and applicable method for day-ahead peak shaving scheduling of cascade hydropower stations.