Economic load dispatch is one of the most important problems in power system operation, therefore the aim of this paper is to establish a method to reduce electricity generation costs with a new approach. This method introduces two new constraints called rate of change of frequency (ROCOF) and minimum frequency as the main constraints in economic dispatch in this paper. This approach reduces emission and fuel costs of the power plants as well as transmission line losses. Therefore, this method has also the capability to control frequency in a desirable range. Finally, the proposed method is simulated on a test system. In the simulation, the economic load flow with is solved with spinning reserve, transmission lines loses and generation constraints as well as the two new mentioned constraints, i.e. ROCOF and minimum frequency constraints. Simulation results obtained from the proposed and conventional methods, show advantages of proposed method. ©2008 IEEE.
