This paper presents an efficient and reliable evolutionary based approach to solve the economic load dispatch (ELD) with lineflows and voltage constraints. The proposed approach employ particle swarm optimization (PSO) algorithm for ELD. Incorporation of Type 1 PSO as a derivative-free optimization technique in solving ELD with voltages and lineflow constraints significantly relieves the assumptions imposed on the optimized objective function. The proposed approach has been tested on three representative systems, i.e. IEEE 14 bus, IEEE 30 bus and IEEE 57 bus systems respectively. The feasibility of the proposed method is demonstrated and the results are compared with Linear Programming, Quadratic Programming and Genetic Algorithm respectively. The developed algorithms are computationally faster than the other methods.