JPS_V4_N2_RP3 Varaprasad Janamala K. Chandra Sekhar Journal on Power Systems Engineering 2322–0376 4 2 26 37 Competitive Electricity Market, Congestion, DE, Loadability, TVAC-PSO, UPFC In a competitive market environment, the provision of strategic bidding to the market participants and its consequences open up new challenging tasks to the system operator. The market economic efficiency is mainly dependent on transmission system support. The inability of transmission system support to drive market cleared schedule is known as congestion which is not desirable. At first stage, Differential Evolution (DE) technique is applied to optimize unconstrained market schedules for active power demand. In the second stage, Time-Varying Acceleration Coefficients-Particle Swarm Optimization (TVAC-PSO) algorithm is applied to minimize reactive power cost by optimizing the Unified Power Flow Controller (UPFC) parameters and voltage profile of the network simultaneously. Due to this approach, the congestion cost with redispatch and more reactive power cost payment to the market participants have been avoided. In addition to this, the system maximum loadability has been reduced. The analysis is carried out on IEEE 14-bus and IEEE 30-bus test systems and the results shown the validity of the proposed work in real-time. May - July 2016 Copyright © 2016 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=8132