Power Generation Scheduling for Integrated Large and Small Hydropower Plant Systems in Southwest China

Abstract

Electric power transmission lines in service in southwest China have fallen far behind the power sources. With rapid development of hydropower in this area, severe water spills for hydropower frequently occur during the flood season because of limited transmission capacity. Effective coordinated operation among large and small hydropower plants (LHPPs and SHPPs) in the area is a feasible approach for alleviating this problem. Using the Yunnan Power Grid (YNPG) of southwest China as an example, a long-term coordinated optimal operation model (COOM) for an integrated system of LHPPs and SHPPs is proposed in this paper. Total electricity that can be consumed or transmitted is defined as electricity absorption. Maximizing the total electricity absorption, which implies balancing high average water heads with reservoir spills, was selected as the objective. Satisfying multiple voltage transmission constraints is a critical issue. A progressive optimality algorithm (POA) was used to solve the model based on a multidimensional search in two-stage optimizations. Results from the YNPG case study show that the proposed method can achieve greater total electricity absorption while effectively reducing spillage.