Effects of hydro models on optimal operation of variable head hydro-thermal systems

In this paper, the problem of optimum short-range scheduling of an integrated hydro-thermal electric power system with variable head hydro plants is considered. The scheduling problem involves the solution of the coordination equations for an arbitrary hydro plant performance model. Of the many models available, the Glimn-Kirchmayer model and the Hamilton-Lamont model are selected for use in deriving specific optimality conditions for the problem. The Newton-Raphson method is the basis of an algorithm developed for solving the problem of optimal power scheduling iteratively. The paper reports on the effect of the form of the hydro plant model on the resulting optimal schedules. Several test systems are used to examine model effects in terms of optimal fuel cost, thermal and hydro generation and transmission losses. Effects of the models on the convergence properties of the algorithm and a comparison of execution times are also reported.