The economic load dispatch plays an important role in the operation of power system,

and several models by using different techniques have been used to solve these problems.

Several traditional approaches, like lambda-iteration and gradient method are utilized to find out

the optimal solution of non-linear problem. More recently, the soft computing techniques have

received more attention and were used in a number of successful and practical applications. The

purpose of this work is to find out the advantages of application of the evolutionary computing

technique and Particle Swarm Optimization (PSO) in particular to the economic load dispatch

problem. Here, an attempt has been made to find out the minimum cost by using PSO using the

data of three and six generating units