A Simplified Lagrangian Multiplier Approach for Fixed Head Short-Term Hydrothermal Scheduling

This paper presents a simplifiedlagrangian multiplier based algorithm to solve the fixed head hydrothermalscheduling problem. In fixed head hydrothermal scheduling problem, waterdischarge rate is modeled as quadratic function of hydropower generation andfuel cost is modeled as quadratic function of thermal power generation. Thepower output of each hydro unit varies with the rate of water dischargedthrough the turbines. It is assumed that hydro plants alone are not sufficientto supply all the load demands during the scheduling horizon. In hydroscheduling, the specified total volume of water should be optimally dischargedthroughout the scheduling period. A novel mathematical approach has been developedto determine the optimal hydro and thermal power generation so as to minimizethe fuel cost of thermal units. The performance of the proposed method isdemonstrated with three test systems. The test results reveal that the proposedmethod provides optimal solution which satisfies the various system constraintsof fixed head hydrothermal scheduling problem.