An innovative approach to generation scheduling in large-scale hydro-thermal power systems with fuel constrained units

An extensive technology is presented for scheduling MW generation in power systems which consist of thermal, fuel constrained, and hydro units. The development of the solution method is based on the Lagrangian relaxation approach. The demand and reserve constraints, the minimum up and down time constraints, the fuel utilization constraints, and the hydro constraints are all considered in the problem formulation. The proposed procedure is especially applicable to systems whose unit commitment solution is sensitive to changes in the Lagrangian multipliers. In this regard, the proposed method incorporates the following special features. First, a set of upper bounds is added to limit the excess in the spinning reserves at different periods during the search for a feasible suboptimal solution. Second, a revised economic dispatch algorithm is introduced in the final stage of the method. This algorithm identifies unnecessarily committed units in the generation schedule of a large power network and provides the solutions for the economic allocation of the system demand among the committed units.<>