Analysing Powe Flow Solution with Optimal Unified Power.Flow Controller

Abstract

Abstract-The electric power system function is to maintain the power plants under pool operation and utility centers to supply the active and reactive powers demanded by the loads connected to the system. Now a day's transmission systems are difficult to operate as well as more stressed due to unscheduled power flows and more losses of growing demand. However many HV systems are operating below thermal rating due to the voltage and stability limit. Later on rapid development in the technology introduces high rating and fast acting switching devices with power electronic components. Flexible AC transmission system (FACTs) controllers equipped with fast acting semi conductor devices designed to control one or more power system parameters for the effective operation of system. In this paper, a novel FACTs controller namely, optimal unified power flow controller (OUPFC) is proposed with its current injection model along with its incorporation procedure. The effect of this device on system parameters is analyzed on standard test systems with its graphical and numerical results.Keyword-Optimal unified power flow controller; Current based model; PST; UPFC I. INTRODUCTION The technological developments in power electronics industry increases the opportunities to develop new kind of flexible AC transmission system controllers popularly known as FACTs controllers. In general, the conventional FACTs controllers can control either the bus voltage magnitude, voltage angle at buses or active and reactive power flow in transmission lines. Due to this, the existing controllers can be called as single function controllers. In real, to solve the practical problems, the realistic controllers must control the multiple system parameters simultaneously rather than single system parameter.This led to the development of FACTS devices over which OUPFC is the effective device developed to improve the power system reliability by controlling the power flow through lines. OUPFC consists of the combination of UPFC and PST which exhibit their individual better features in controlling power flows in transmission lines. UPFC able to control real, reactive power flows and voltage magnitude at the buses and PST controls phase angle of the bus voltages [1-2].Previously power injection and voltage based models have been developed to model the FACTS devices. Anew approach to model OUPFC is developed known as current based model. This model shows the better convergence and reliability of the existed system [3]. Recent literature reveals PIM of OUPFC for optimal power system performance. This model was tested with OPF algorithm to optimize the fuel cost and loss [4]. A. Lashkar Ara et al., developed contingency analysis based OUPFC to minimize average loadability on transmission system and to enhance system security under single contingency condition [5].After careful review of the literature, it is noticed that, using optimal unified power flow controller (OUPFC) multiple system parameters can be controlled. The existing literature presents the power...