Daily peak shaving operation of mixed pumped-storage hydro plants considering cascade hydraulic coupling

Abstract

Growing peaking regulation pressure of the thermal-dominant power grid in China caused by increasing peak–valley differences is of concern in recent years. As the second largest power supply in China, hydropower is an important supporting resource for daily peak shaving operations. It is effective to install new pumped-storage hydro turbines (PSHT) based on the constructed cascade reservoirs to make full use of water resources, which is become a popular measure recently. This paper investigates the peak shaving of cascade hydropower with mixed pumped-storage (CHMPS) to reduce the variance of the residual load of the external grid. The hydraulic constraints, unit operation constraints, and impact of water head on unit generation are considered to formulate a precise model. The nonlinear and nonconvex problem is linearized and converted into a mixed-integer quadratic programming (MIQP) problem to enhance computational efficiency. Simulation results based on a hydropower system in China verify the effect of the proposed model on daily peak shaving.

Keywords

• Cascade hydropower
• Pumped-storage hydro turbine
• Peak shaving
• Uncertain river inflow