ICEEAC 2013 International Conference on Electrical Engineering and Automatic Control, Setif, 24-26 November 2013 Particle Swarm Optimization for Solving the Economic Load Dispatch Including Wind Energy Y. Salhi * , F. Benhamida * , B. Bouchiba # , I. Ziane * * IRECOM Laboratory, Department of Electrical Engineering, University of Djillali Liabes, Sidi Bel Abbes # CAOSEE Laboratory, Faculty of sciences and technology, University of Bechar, Algeria salhiyacine13@yahoo.fr, farid.benhamida@yahoo.fr, bouchiba_bousmaha@yahoo.fr, ziane_ismail2005@yahoo.fr Abstract- Economic load dispatch among thermal units is one of the most important problems in power systems operation. Usually so called equal marginal cost criterion is adopted to this calculation. Recently global trend of utilizing more and more renewable energy such as wind power makes this problem more important than ever. With the continuing search for alternatives to conventional energy sources, it is necessary to include wind energy generators (WEG) in the ELD problem. This paper presents a solution of economic load dispatch incorporation wind energy using a particle swarm optimization algorithm (PSO). The effect of wind energy generators system inclusion on ELD problem is investigated, with the source wind susceptible to short duration variations, which is the uncertainty of wind speed around a short-duration- stable mean value. A six unit test system is resolved using PSO to illustrate the variation in the optimal cost, losses, and system-λ with the variation of short-duration- stable mean wind speed. I. INTRODUCTION As one of the most promising non pollution renewable energy resources wind power has given more consideration [1]. Comparing with the conventional generators, wind generator has advantage of reducing the dependences on fossil fuels and transmission losses, enhancing the independence and flexibility of large power grids [2]. The classic problem of economic load dispatch (ELD) has inducing new interest with debate on how wind energy generators (WEG) are to be taken into consideration within dispatch schedules [3]-[4] taking into consideration the variability of wind speed. In the past, this problem has been studied for some time as an advance of ELD [5]; while recently works focus on WEG units independently [6], with proper cost components. Availability of wind power is used to formulate ELD problem constraints in [7] and [8]. Most of these works [6] –[8] used a valid statistics distribution [9], [10] to represent variability of wind known as Weibull distribution. The optimal solution of an ELD is defined for short time duration as the validity interval of ELD for many applications, where the Weibull distribution is not the best statistical model for wind speed variations [10], [11]. Short time duration wind speed variations include turbulence and gusts. The turbulence is the random variations on a stable mean wind speed value (u), while the gusts are surges within turbulent wind fields [12]. The Gaussian distribution has been used to model the turbulence and gusts modeled around the stable mean wind speed. In ELD problem model, the stochastic models of power outputs are not taken into account. Practically the conventional units are under influence of small variations over the set point of power, while the load demand varies according to consumer behavior. The generation allocation levels of ELD do not attempts to meet instantaneous values of power demand but a total equivalent power demand in a valid interval. The B-coefficients method has been used in the classical ELD to simulate the total transmission loss [3], [4]. The B- coefficients representation is more compatible with WEG units generation output only if an acceptable total WEG output power generation is used [12], [13]. In this paper we propose a PSO method to solve the ELD problems by including WEG units in the power system to show the effect on optimal generation cost. To study these aspects separately, some of the conventional constraints of the ELD problem have been ignored. II. ELD INCLUDING TRANSMISSION LOSSES The B-coefficients loss formula of ELD problems [3] is     N N N L n n1 n1,n2 n2 n,0 n 0,0 n1 n2 n P P = Pb P+ b .P +b   (1) where the parameters bn1,n2, bn,0, and b0,0 are B- coefficients known for a specific unit. The augmented loss function due to the including of WEG units within a power system would add three additional summations      N N N L n ω n1 n1,n2 n2 n,0 n 0,0 n1 n2 n N W W n n,ω ω ω,0 ω n1 ω ω W W ω1 ω1,ω2 ω2 ω1 ω2 P P ,P = Pb P+ b .P +b + Pb P+ b .P + Pb P               (2)