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Mathematical Problems in Engineering
Volume 2012 (2012), Article ID 838629, 20 pages
Research Article

Optimal Location and Sizing of UPQC in Distribution Networks Using Differential Evolution Algorithm

Department of Electrical Engineering, Faculty of Engineering, University of Kashan, Kashan 87317-51167, Iran

Received 26 January 2012; Revised 14 June 2012; Accepted 29 June 2012

Academic Editor: Hung Nguyen-Xuan

Copyright © 2012 Seyed Abbas Taher and Seyed Ahmadreza Afsari. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Differential evolution (DE) algorithm is used to determine optimal location of unified power quality conditioner (UPQC) considering its size in the radial distribution systems. The problem is formulated to find the optimum location of UPQC based on an objective function (OF) defined for improving of voltage and current profiles, reducing power loss and minimizing the investment costs considering the OF's weighting factors. Hence, a steady-state model of UPQC is derived to set in forward/backward sweep load flow. Studies are performed on two IEEE 33-bus and 69-bus standard distribution networks. Accuracy was evaluated by reapplying the procedures using both genetic (GA) and immune algorithms (IA). Comparative results indicate that DE is capable of offering a nearer global optimal in minimizing the OF and reaching all the desired conditions than GA and IA.