Economic Power Dispatch of Power Systems with a NOx emission Control via an Evolutionary Algorithm

This paper presents solution of optimal power flow (OPF) problem of medium-sized power systems via a genetic algorithm of real type. The objective is to minimize the total fuel cost of generation and environmental pollution caused by fossil based thermal generating units and also maintain an acceptable system performance in terms of limits on generator real and reactive power outputs, bus voltages, shunt capacitors/reactors, transformers tapsetting and power flow of transmission lines. CPU times can be reduced by decomposing the optimization constraints of the power system to active constraints manipulated directly by the genetic algorithm, and passive constraints maintained in their soft limits using a conventional constraint load flow. Simulation results on the IEEE 30-bus network with 6 generators show that by this method, an optimum solution can be given quickly. Further analyses indicate that this method is effective for medium-scale power systems. Key-Words: Optimal Power Flow, Power Systems, Pollution Control, NOx emission and evolutionary algorithm