OICC Press Signal Processing and Renewable Energy (SPRE) 2588-7335 1 1 2017 03 01 Mid Term Unit Commitment Using Modified Particle Swarm Optimization 11 22 EN Hasan Siahkali Electrical Engineering Department, South Tehran Branch, Islamic Azad University, Tehran, Iran. Journal Article 2017 03 01 This paper presents a new approach to unit commitment (UC) problems using a particle swarm optimization (PSO) technique. The mid term UC problem has a cost function with equality and inequality constraints that make the problem of finding the global optimum difficult by using any mathematical approach. In this paper, a modified PSO (MPSO) mechanism is suggested to deal with the equality and inequality constraints in the UC problems. The proposed MPSO is applied to a 10-unit test system and the results of the MPSO are compared with the results of conventional numerical methods such as mixed integer nonlinear programming (MINLP).