Secant method for Unit Commitment with Ramp Rate Constraints

Abstract

This paper presents an application of a combined improved pre-prepared power demand (IPPD) table and secant method for solving the unit commitment (UC) problem of thermal units with ramp rate constraints. The UC problem is solved in two steps. First, the IPPD table obtains the information of committed units at each predicted power demands. Second, the procedure of economic dispatch (ED) is used to find the optimal allocation of the online generating units. Here ED sub problem is solved by secant method. The proposed method has been tested on a power system having 4 and 38 units for a scheduling horizon of 24 hours. Simulation results of the proposed method have been compared with existing methods. The comparison of results of the proposed method with the results of previous published methods shows that the proposed approach provides better qualitative solution with less computational time.