Optimal Generation Scheduling of Hydropower Plant with Pumped Storage Unit

Abstract

The generation scheduling problem of hydropower plant in the presence of pumped storage unit is complex. This work has proposed a solution strategy to determine the optimum generation based on the analysis of hourly and annual generation costs. The hourly and annual costs are linear functions of power output and energy generation, respectively. The power output was formulated as a linear function of hydraulic head and discharge rate, without computing the conversion efficiency from a hill diagram. The mathematical relationships between power, hydraulic head, and discharge rate can be determined from loading & efficiency test data and validated by using a field test. The optimum generation was stated as capacity factor and varied with water drawdown of the plant. The optimum time interval and duration of the pumped storage unit can be determined by analyzing the hourly marginal operating costs, simplified by using a composite cost function. The proposed strategy has been simulated with the generation data of the Bhumibol hydropower plant.

Keywords: generation scheduling, hydropower plant, pumped storage