M C V SURESH 01 3 Controlling power flow in modern power systems can be made more flexible by the use of recent developments in power electronic and computing control technology The Unified Power Flow Controller UPFC is a Flexible AC transmission system FACTS device that can control all the three system variables namely line reactance magnitude and phase angle difference of voltage across the line The UPFC provides a promising means to control power flow in modern power systems Essentially the performance depends on proper control setting achievable through a power flow analysis programThe paper presents a reliable method to meet the requirements by developing a NewtonRaphson based load flow calculation through which control settings of UPFC can be determined for the prespecified power flow between the lines The proposed method keeps NewtonRaphson Load Flow NRLF algorithm intact and needs little modification in the Jacobian matrix A MATLAB program has been developed to calculate the control settings of UPFC and the power flow between the lines after the load flow is convergedCase studies have been performed on IEEE 5bus system to show that the proposed method is effective These studies indicate that the method maintains the basic NRLF properties such as fast computational speed high degree of accuracy and good convergence rate Copyright (c) World Journal of Pharmaceutical Seiences. All rights reserved 2026