International Review on Modelling and Simulations (I.RE.MO.S.), Vol. 3, N. 6 December 2010 Manuscript received and revised November 2010, accepted December 2010 Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved 1492 Genetic Algorithm-Based Optimal Location of TCSC and SSSC in the Power System Network M. Karami, N. Mariun, M. Z. A. Ab Kadir Abstract FACTS controllers are based on power electronics technology. They are able to control three main parameters of transmission line such as voltage magnitude, voltage angle and line impedance. Different types of FACTS devices and their various locations in the power system have different effects. In this paper, a practical, accurate and famous heuristic method in engineering science known as genetic algorithm (GA) is used to find the optimal location of FACTS devices and their appropriate size and setting is presented. This method is employed to maximize distance to collapse point of power system and to reduce total active power loss. The continuation power flow (CPF) method is operated to identify the collapse point and critical situation of system. Two types of FACTS devices considered in this study are Thyristor Controlled Series Capacitor (TCSC) and Static Synchronous Series Compensator (SSSC). Modeling and simulation are performed on IEEE 14, 57 and 118 bus test system. The acquired results clearly display the effectiveness of this study to find the best location, appropriate size and setting of FACTS devices to achieve mentioned objectives. Furthermore, the results show the effect and capability of FACTS devices to modify different parameters of power system. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved. Keywords: TCSC, SSSC, Voltage Collapse, Continuation Power Flow Analysis, Genetic Algorithm Nomenclature The nonlinear vector function The state variable of system The algebraic variables vector The variable loading levels The controllable parameters of system u A set of system variables and parameters A set of variables and The normalized zero eigenvector The initial operating point c(u) The constraints The function of nonlinear vector and algebraic functions which correspond to state variables, load bus voltages and angles The system Jacobian The crossover probability The mutation probability The offspring chromosome and The chromosome of parents The number of gene in chromosome The random constant in [0, 1] The power loss difference between the without FACTS and with FACTS devices in power system F(b,v) The conventional power flow equations (s) The constraint for FACTS devices (v) The constraint for conventional power flows I. Introduction Based on deregulation and privatization (a separation of generation and transmission) of the electric power market in addition to increasing load demand and regarding the specific property of the product of this industry (electricity), i.e., the impossibility of reservation, establishment of equilibrium between electricity production and consumption is the major motive in design and implementation of the new structure. At the same time, the limitation of generation, because of the supply of electric energy does not merely include the simple process of transmission and distribution. However, it is very important to observe certain considerations such as the establishment of safety, dependability, stability, minimize losses, management of density and many other aspects. According to technical issue, it can be observed an enhancement of spontaneous power exchanges since rivalry between utilities and contracts is derived directly among manufacturers and buyers. Therefore, it may cause a hardship like overload if the exchanges are not controlled. This event is named congestion, so we cannot use all the capacity of the power system [1]. After deregulation of electric industry, it seems that the control