Optimization of an Operation Strategy for Variable Speed Pumped Storage Power System Flexibility

Abstract

With the increase in the grid-connected scale of new energy, the ability to flexibility regulate a power system is greatly challenged. Since a variable speed pumped storage (VSPS) unit has a wider power regulation range and higher operation efficiency than conventional pumped storage (CPS), this study focuses on improving system flexibility with the VSPS unit. First, the probabilistic characteristics of forced outages affecting the flexibility of power units are studied. Considering the uncertainty of the net load prediction error, a probabilistic density method is proposed to quantify the flexibility of the power system. Second, in order to improve the flexibility of the system and take into account the comprehensive benefits of the VSPS unit, an optimization model for the VSPS unit to improve the flexibility of the grid was established based on bacterial colony chemotaxis that takes into consideration the operational constraints of the VSPS unit. Finally, to verify the effectiveness of the proposed optimization strategy using simulation, the proposed optimization model is used to compare the advantages of the VSPS unit’s ability to regulate system flexibility with a conventional pumped storage unit.