I. Introduction
Economic dispatch (ED) is one of the major optimization issues in power systems. It aims at allocating the power generation among the generators while meeting the constraints of total load demand as well as respecting individual resource capacity limits. The traditional optimization methods (e.g., gradient search method [1], lambda iteration method [2]) and the intelligent computational methods (e.g., genetic algorithm [3], particle swarm optimization [4], [5]) have been extensively applied to solve the ED problem in a centralized fashion.