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

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 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 optimality conditions for the problem. The Newton-Raphson method is the basis of an algorithm developed solving the problem of optimal power scheduling iteratively. The authors report on the effect of the form of the hydro plant model on the resulting optimal scheduling. 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.