A Simplified LagrangianMultiplier Approach for Fixed Head Short-Term Hydrothermal Scheduling

This paper presents a simplified lagrangian multiplier based algorithm to solve the fixed head hydrothermal scheduling problem. In fixed head hydrothermal scheduling problem, water discharge rate is modeled as quadratic function of hydropower generation and fuel cost is modeled as quadratic function of thermal power generation. The power output of each hydro unit varies with the rate of water discharged through the turbines. It is assumed that hy dro plants alone are not sufficient to supply all the load demands during the scheduling horizon. In hydro scheduling, the specified total volume of water should be optimally discharged throughout the scheduling period. A novel mathematical approach has been developed to determine the optimal hydro and thermal power generation so as to minimize the fuel cost of thermal units. The performance of the proposed method is demonstrated with three test systems. The test results reveal that the developed method provides optimal solution which satisfies the various system constraints of fixed head hydrothermal scheduling problem.