Hydrothermal scheduling of a multireservoir power system with stochastic inflows

A suboptimal method for solving the annual hydrothermal scheduling problem for a multireservoir hydrothermal system is presented. Hydrothermal scheduling is performed in order to find the optimum allocation of hydro energy so that the annual operating cost of a mixed hydrothermal system is minimized. In the present work, the hydrothermal scheduling problem is formulated as a constrained optimization problem which is decomposed into three subproblems; maintenance scheduling of thermal units, dispatch of thermal units, and dispatch of hydroplants. The algorithm takes into consideration the stochastic nature of the water inflows to the reservoirs and the forced outage rates of the thermal units. Results obtained by the application of the algorithm to a simplified version of the Hellenic Hydrothermal Power System, showing the effect of the hydroplants, are reported