Abstract: This paper proposes a Evolutionary Programming (EP) and Particle Swarm Optimization (PSO) algorithms to solve Economic Dispatch (ED) problems considering of prohibited operating zones, ramp rate limits, generator capacity limits and power balance constraints. The PSO method was developed through the simulation of a simplified social system and has been found to be robust in solving continuous nonlinear optimization problems in terms of accuracy of the solution and it can out perform other algorithms The EP and PSO algorithms are applied for the ED of three unit, six unit and fifteen unit thermal systems. The numerical results shows that the comparision of EP and PSO algorithms with some other other modern metaheuristic optimization methods reported in the recent literatures.

Keywords: Economic dispatch, Evolutionary programming, Particle swarm optimization, , Prohibited operating zones, Ramp rate limits.