The effect of unified power flow controller location in power systems Mehmet Tu¨maya (original) (raw)

Injection Power Upfc Model for Incorporation of Unified Power Flow Controller in Load Flow Studies

JES. Journal of Engineering Sciences, 2007

This paper is devoted to the incorporation of the steady-state model of the unified power flow controller (UPFC) in power flow programs using a UPFC injection model. The adopted UPFC injection model is based on the representation of UPFC in steady-state conditions by two voltage sources in series with certain reactances. Using this UPFC power flow model, the effects of UPFC control variables on system voltage magnitude, line active and reactive power flow, total system losses, slack bus generated active and reactive power and the injected reactive power from voltage controlled buses are illustrated. Also, the effects of the UPFC location and the UPFC series converter coupling transformer reactance on power flows and on total system real power loss are studied. It is found that using this UPFC power flow model it is possible to show the power flow characteristics inside the UPFC converters, themselves.

A REVIEW ON INCORPORATION OF UNIFIED POWER FLOW CONTROLLER (UPFC) FOR POWER FLOW CONTROL

In these paper, we discuss and study about one of the most versatile flexible alternating current transmission system (FACTS) device which is unified power flow controller (UPFC). By using unified power flow controller can control all power system parameters individually or simultaneously. The purpose of this paper is to present a comprehensive survey of UPFC controller incorporated in load flow analysis for optimal power flow control. We also discuss different controlling mechanism for dynamic model of UPFC and different optimization techniques for the optimal placement. Ⅰ. INTRODUCTION Flexible Alternating Current Transmission Systems (FACTS) devices have been widely used in power systems around the world. These devices are used to enhance the controllability and increase the power transfer capability of the electrical network. The semiconductor devices such as diodes, transistors, thyristors and gate turn-off thyristors (GTO) are applied to develop the various types of FACTS. The FACTS devices have the ability to control many parameters of transmission systems such as; the series impedance, the shunt impedance, the current, the voltage magnitude, and the phase angle. FACTS controllers are power electronics based system and other static equipment that have the capability of controlling various electrical parameters in transmission networks which can be adjusted to provide adaptability conditions of transmission network. FACTS controllers have been proved that they can be used to enhance system controllability resulting in total transfer capability (TTC) enhancement and minimizing power losses in transmission networks [5]. The maximum performance of using FACTS controllers to increase TTC and minimize losses should be obtained by choosing the optimal numbers, parameter settings, and locations in transmission systems. Modern heuristics optimization techniques are successfully implemented to solve complicated optimization problems efficiently and effectively [4]. Unified Power Flow Controllers (UPFCs) are the most versatile and complex power electronic equipment applied for the control and power flow optimization in electrical power transmission systems. It offers major potential advantages for the static and dynamic operation of transmission lines. The UPFC combines the functions of several FACTS devices and is capable of implementing voltage regulation, series compensation, and phase angle regulation at the same time, thus realizing the separate control of the active power and reactive power transmitted simultaneously over the line. The UPFC thus provides effective means for controlling the power flow and improving the transient stability in a power network. [1] Unified Power Flow Controller (UPFC) is the most effective Flexible Alternating Current Transmission System (FACTS) device which is able to maximize the power transfer capability of interconnected power systems. [7]The UPFC can be used to control the line power flow and voltage bus individually or simultaneously. Now, the implantation of FACTS devices in load flow algorithms is considered as a fundamental requirement in planning, operation, and control. Generally, the existing load flow programs need to be modified to incorporate these devices. The required modifications due to many reasons such as; addition reference buses related to the number of FACTS have to be added in the network, the impedances of FACTS have to be incorporated into original admittance matrix, and the powers contributed by FACTS have to be included into power mismatches vector. Some of excellent research works have been done to reduce the complexity of load flow programs with the UPFC device [5].The UPFC is the most powerful and versatile FACTS-equipment used to control the power flow and stability of the power system. The UPFC uses solid state devices, which provide functional flexibility, generally not attainable by conventional thyristor controlled systems [12]. The UPFC is a combination of a static synchronous compensator (STATCOM) and a static synchronous series compensator (SSSC) coupled via a common DC voltage link. The DC terminal of the two converters is connected together with a DC capacitor. The series converter control to inject voltage magnitude and phase angle in series with the line to control the active and reactive power flows on the transmission line. Hence the series converter will exchange active and reactive power with the line. UPFC can be act static as well as dynamic condition also. Static is an analysis at the steady state condition and dynamic is an analysis at the transient condition such as faults occurs in transmission system. It provides the ability to simultaneously control all the transmission parameters of power systems, i.e. voltage, impedance and phase angle [11].

Unified power flow controller (UPFC): modeling and analysis

IEEE Transactions on Power Delivery, 1999

The Unified Power Flow Controller (UPFC) is a novel power transmission controller. The UPFC provides a full dynamic control of transmission parameters, voltage, line impedance and phase angle. This paper presents a useful tool for power utilities engineers to evaluate the application of the IIPFC, its impact on their power system and what would be the shunt and series ratings. This paper gives sets of equations for a system including the UPFC and an equivalent two bus power network. A numerical method tested with Matlab has been successfully validated with analog model and EMTP. The Matlab code given in the paper allows to perform fast parametric studies for the application of the UPFC.

DESIGN, CONTROL AND SIMULATION OF UNIFIED POWER FLOW CONTROLLER USING MATLAB

The UPFC is a versatile controller which can be used to control active and reactive power flows in a transmission line. The concept of UPFC makes it possible to handle practically all power flow control and transmission line compensation problems, using solid state controllers, which provide functional flexibility, generally not attainable by conventional thyristor controlled systems. In this paper, we proposed a control strategy for UPFC, modeling of UPFC using MATLAB SIMULINK and to analyze the control strategy to use the series voltage injection and shunt current injection for the UPFC control.

Steady-state and dynamic models of unified power flow controller (UPFC) for power system studies

Power Systems, IEEE …, 1996

This paper provides comprehensive development procedures and final forms of mathematical models of unified power flow controller (UPFC) for steadystate, transient stability a$ eigenvalue studies. Based on the developed models, the impacts of control strategy, parameters and location of UPFC on power system operating conditions are discussed. The accuracy of the developed models is verified through comparing the study results with those obtained from detailed time-domain simulation using the Electromagnetic Transients Program (EMTP).

Unified Power Flow Controller (UPFC) Modeling and Analysis Technique by using Matlab and EMTP

Renewable Energy and Power Quality Journal

The UPFC is a state-of-the-art control device that has the ability to enhance electrical power system network operation more precisely and effectively. This device encompasses of shunt and series parts to readjust capacitive and inductive compensation of the network based on their ratings to dynamically control the operating parameters of the transmission-network. These dynamic parameters comprise of phase angles, line impedance and line voltage. During the detailed investigation, a set of equations are introduced to compute UPFC operations/control behaviour on shared two bus system networks. In fact, the EMTP and Matlab models are introduced and customized to determine and validate UPFC effectiveness with precision. In this investigation, a pragmatic approach demonstrated and provided roadmap for the planning and control electrical engineer to evaluate UPFC operational behaviour and its significant impact on Electrical power transmission network operations. This device has the ability to address all types of time based contingencies in order for a seamless operation.

A study of Unified Power Flow Controller ( UPFC ) in Power System — A Review

2019

This paper proposes a new real and reactive power coordination controller for a unified power flow controller (UPFC). The basic control for the UPFC is such that the series converter of the UPFC controls the transmission line real/reactive power flow and the shunt converter of the UPFC controls the UPFC bus voltage/shunt reactive power and the DC link capacitor voltage. In steady state, the real power demand of the series converter is supplied by the shunt converter of the UPFC. This paper also presents the characteristics of two gate turn-off (GTO) thyristor voltage-sourced inverterbased series power flow control devices, namely the Series Power Flow Controller (SPFC) and the Unified Power Flow Controller (UPFC). These devices represent series extensions of the STATCOM, an inverter-based shunt device developed under a tailored collaboration by EPRI, TVA and the Westinghouse Science and Technology Center, which will soon be placed in service on the TVA lGlkV transmission system for ...

Performance evaluation of unified power flow controller using transient simulation

Proceedings of Second International Conference on Power Electronics and Drive Systems, 1997

The Unified Power Flow Controller (UPFC) is a power electronic controller which can be used to control active and reactive power flows in a transmission line by injection of (variable) voltage in series and reactive current in shunt. In this paper we evaluate the performance of a control strategy for UPFC in which we control real power flow through the line, while regulating magnitudes of the voltages at its two ports using transient simulation. The real power reference is modulated in order to improve the damping of power swings in the line. The effectiveness of the UPFC with this control strategy is clearly brought out by the simulation study T0pic:Applications: FACTS; Computer Simulation.

A Literature Review on the Unified Power Flow Controller UPFC

International Journal of Computer Applications, 2018

Power electronic controllers for a flexible ac transmission system (FACTS) can offer a greater control of power flow, secure loading and damping of power system oscillations. A unified power flow controller (UPFC) is a one of FACTS elements that can provide VAR compensation, line impedance control and phase angle shifting. The UPFC consist of two fully controlled inverters, series inverter is connected in series with the transmission line by series transformer, whereas parallel inverter is connected in parallel with the transmission line by parallel transformer. The real and reactive power flow in the transmission line can be controlled by changing the magnitude and phase angle of the injected voltage produced by the series inverter. The basic function of the parallel inverter is to supply the real power demanded by series inverter through the common dc link. The parallel inverter can also generate or absorb controllable reactive power. This paper offers and discusses most papers that used a UPFC to improving the active and reactive power flow of the power systems.

Versatile control strategy of the unified power flow controller (UPFC)

2000 Canadian Conference on Electrical and Computer Engineering. Conference Proceedings. Navigating to a New Era (Cat. No.00TH8492), 2000

The Unified Power Flow Controller (UPFC) is a third generation Flexible ac Transmission System (FACTS) that uses solid state electronics to control the flow of power through lines in a faster and more economical fashion. In this paper, we propose a versatile control strategy of the UPFC that joins shunt active filtering and system balancing capabilities to real time power flow control into one device. To achieve optimal UPFC behaviour in the different mode, the controllable system parameters are determined on-line based on the local instantaneous voltage and current measurements. The strategy is based on the theory of instantaneous parameters defined in the positive, negative and zero sequence with real and imaginary components. The power flow calculation should not involve any conventional definitions of power, the Fortescus transformation will be used to conform the relation of the instantaneous active and reactive power with the steady state power values. The control algorithm compensates the oscillated part of the instantaneous active power and reactive power component to achieve the harmonics compensation without any rms value calculation of voltage and current. The UPFC and the transmission system model has been developed in Simulink environment for the digital simulation to demonstrate the versatility of the new control strategy. Interesting results have been obtained, which are presented in this paper.