JPS_V3_N4_RP1 M. Lakshmikantha Reddy M. Ramprasad Reddy V.C. Veera Reddy Journal on Power Systems Engineering 2322–0376 3 4 1 11 Optimal Power Flow, Gravitational Search Algorithm, Security Constraints, Quadratic Fuel Cost The operation of an electric power system is a complex one due to its nonlinear and computational difficulties. One task of operating a power system economically and securely is optimal scheduling, commonly referred to as the Optimal Power Flow (OPF) problem. It optimizes a certain objective function while satisfying a set of physical and operating constraints. Optimal power flow has become an essential tool in power system planning and operation. In this paper, a gravitational search algorithm is presented to solve OPF problems while satisfying system equality, in-equality constraints. The effect of security limits such as transmission line limits and load bus voltage magnitudes is also analyzed on OPF problem. The developed methodology is tested on the standard IEEE-30 bus test system, supporting numerical and as well as graphical results. November 2015 - January 2016 Copyright © 2016 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=4800