A Method for Estimating the Power Duration Curves of the Project Power in a Large Combined Hydro-Steam Power System

Abstract

In planning electric power generation of a large combined hydro-steam power system, we should determine not only the power and energy but also the power duration curve, which is necessary to calculate the energies, generating hours and start-stop frequencies of each generating unit. The project power, which includes the existing steam power, will be found from the predicted load after subtracting the part assigned to the existing hydro plants. In general, the past data show that the curve, represented by the vertical distance between the duration curves of load and that of hydro power, will be greatly different from the steam power duration curve of the corresponding year. In this paper, the authors try to find out a method in which the duration curves of the predicted steam power, estimated by utilizing the past data of load and hydro power, are closely matching with the actual duration curve of steam power in the corresponding year. The diagrams, calculated by this method from the past data of a certain power system, are expected to be applicable in estimation of the duration curves of project power in near future, at least for the same power system.