MODELING THE INCREMENTAL COST AND WATER CONVERSION FUNCTIONS FOR HYDRO-THERMAL COORDINATION STUDIES

Abstract

ABSTRACT The solution of an optimization problem using variational means relies on Lagrange multiplier functions, called the adjoint variables to augment the physical constraints to the cost function. The multipliers usually have an economic interpretation, and in the optimal economic operation of an electric power system, one set of multipliers signifies the incremental cost of power delivered at a bus, and the other set relates to the water worth at a given reservoir. The solution of the optimization problem involves iterative techniques to obtain the optimal strategy in terms of power generations and water releases, as well as the adjoint variables. Good initial estimates are of paramount importance to a successful implementation of any iteration scheme specially those that are Newton based. There is an observed pattern of dependence of the adjoint variables and the system state as described by power demands and water availability. Finding such relationships is useful for generation planning activities...