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Dynamic Stability Enhancement of a Multi Machine Electric Power System Using Unified Power Flow Controller
Ahmad Memaripour,Sayed Mojtaba Shirvani Boroujeni,Reza Hemmati
Research Journal of Applied Sciences, Engineering and Technology , 2011,
Abstract: This study presents the application of Unified Power Flow Controller (UPFC) to improvement dynamic stability of a multi-machine electric power system installed with UPFC. Since UPFC is considered to mitigate Low Frequency Oscillations (LFO) and stability enhancement, therefore a supplementary stabilizer based on UPFC (like power system stabilizer) is designed to reach the defined purpose. Intelligence optimization methods such as Particle Swarm Optimization (PSO) and Genetic Algorithms (GA) are considered for tuning the parameters of UPFC supplementary stabilizer. To show effectiveness of UPFC and also comparing these two optimization methods, the proposed methods are applied and simulated. Several nonlinear time-domain simulation tests visibly show the ability of UPFC in damping of power system oscillations and consequently stability enhancement. Also Simulation results emphasis on the better performance of PSO based Stabilizer in comparison with GA based Stabilizer.
Improving Transient Stability of a Multi-Machine Power Network Using FACTS Devices and Nonlinear Controller Tuned by PSO  [cached]
M.A. Ashraf,S. Shojaeian,H.R. Koofigar
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: Transient stability is one of the main issues in the field of power systems. On the other hand, using FACTS devices has been proposed for the purpose of maximizing the lines conductivity given the restrictions involved, including the issue of stability. This study seeks to take steps towards the improvement of a multi-machine power system stability in faulty conditions, using two FACTS devices including TCSC and SVC. The control system for the FACTS devices is constructed here based on the so called energy function method. Meanwhile, in order to achieve a prescribed optimal performance, the coefficients of the designed controller are tuned by PSO algorithm. Possessing the theoretical analysis, the simulation results are also demonstrated to show the performance of the proposed control algorithm.
Investigating the Capability of Power Flow Regulation by Unified Power Flow Controller (UPFC) in a Single-Machine-Infinite Bus System
Mark Ndubuka NWOHU
Leonardo Journal of Sciences , 2007,
Abstract: The capability of regulating power flow in Nigerian Grid System using UPFC is the main focus in this paper. Consequently, three control methods, namely, voltage control through shunt compensation, real power flow control through quadrature voltage injection and reactive power flow control through in-phase voltage injection for the UPFC were examined in order to improve the transient stability of the power system. The quadrature voltage control was found to be effective in reducing the transient swings whereas in-phase voltage control was effective in improving the transient stability margin. Finally, the overall performance of the UPFC was evaluated in a single-machine infinite bus system by nonlinear simulations, and results obtained showed the effectiveness of the controller in improving the dynamic stability of the system and provide better damping to electromechanical oscillations.
A Novel Power System Stabilization Technique Using Non-Dominated Ranked Genetic Algorithm
V. Ravi,K. Duraiswamy
International Journal of Soft Computing , 2012, DOI: 10.3923/ijscomp.2012.50.57
Abstract: In order to deal with wide range of operating environment and disturbance, Power System Stabilizers (PSS) should be developed with appropriate stabilization signals. Recently, stabilizing control techniques for the Multi-Machine Power System with the help of intelligent methods have been developed. The main aim for the stability analysis of the power system is because of the importance of the power systems in the present world. Moreover, industries do not encourage the controller design if power system stability is not significant. In order to handle the above mentioned problems, intelligent approaches are used. The optimal sequential design for Multi-Machine Power Systems is very vital and many techniques are widely used to deal with control signals in power system. Most widely used optimization technique is Genetic Algorithm (GA). But GA takes more time in optimization and lack in accuracy. To overcome the above mentioned issues, this study uses Non-dominated Ranked Genetic Algorithm (NRGA) for optimization. Simulation results suggest that the proposed stabilization approach is better when compared to the conventional techniques.
Low Frequency Power Oscillation Damping Enhancement and Voltage Improvement Using Unified Power Flow Controller (UPFC) in Multi-Machine Power System
Nwohu Mark Ndubuka
International Journal of Electrical and Power Engineering , 2012, DOI: 10.3923/ijepe.2011.174.180
Abstract: The problem of low-frequency power swings is a matter of concern for power systems engineers in the operation and planning of power systems. Therefore, this study is an investigation of the use of Unified Power Flow Controller (UPFC) that is suitably tuned to improve the damping of low frequency power oscillations present in Nigerian grid system. A large disturbance is initiated during simulation in PSAT in the network to induce nonlinear oscillations of the power system in order to ascertain the damping effect of UPFC. The dynamic responses of the system simulated show that the system is well damped and is stabilized at minimal time which confirms the robustness of the UPFC. Finally, a comparative study in a typical transient stability problem on IEEE 14-bus system using a UPFC model and the Nigerian high voltage interconnected system is used to illustrate the concepts presented in this study.
A Novel Power System Stabilization Technique using Advanced Genetic Algorithm Optimization Approach  [PDF]
V. Ravi,Dr.K. Duraiswamy
Bonfring International Journal of Power Systems and Integrated Circuits , 2012,
Abstract: In order to deal with wide range of operating environment and disturbance, Power System Stabilizers (PSS) should be developed with appropriate stabilization signals. Recently, stabilizing control techniques for the multimachine power system with the help of intelligent methods have been developed. The main aim for the stability analysis of the power system is because of the importance of the power systems in the present world. Moreover, industries do not encourage the controller design if power system stability is not significant. In order to handle the above mentioned problems, intelligent approaches are used. The optimal sequential design for multi-machine power systems is very vital and many techniques are widely used to deal with control signals in power system. Most widely used optimization technique is Genetic Algorithm (GA). But, GA takes more time in optimization and lack in accuracy. To overcome the above mentioned issues, this paper uses Non-Dominated Ranked Genetic Algorithm (NRGA) for optimization. Simulation results suggest that the proposed stabilization approach is better when compared to the conventional techniques.
Delay-independent stabilization for steam valve opening of multi-machine power system with sector actuator
具有扇形执行器的多机电力系统气门开度的时滞无关镇定(英文)

SUN Miao-ping,NIAN Xiao-hong,PAN Huan,
孙妙平
,年晓红,潘欢

控制理论与应用 , 2012,
Abstract: A time-independent decentralized controller and a robust decentralized controller have been developed for the steam valve opening of multi-machine power system with sector saturating actuator. The nonlinear interconnected function is first converted by trigonometric transformation into quadratically bounded inequalities in the subsystem states; and then, linear matrix inequality (LMI) sufficient conditions for the closed-loop multi-machine power system and uncertain system to be asymptomatically stable are derived based on Lyapunov stability theory. A two-machine infinite-bus system is considered as an application example. Simulation results demonstrate the effectiveness of the proposed method.
Improvement of Power System Performance Using Fuzzy Logic Based Interline Power Flow Controller [IPFC]  [PDF]
S. N. Dhurvey, V. K. Chandrakar
Journal of Power and Energy Engineering (JPEE) , 2016, DOI: 10.4236/jpee.2016.44007
Abstract: In this paper, the nonlinear dynamic model of a multi machine power system incorporated with Interline Power Flow Controller [IPFC] has been developed for improvement in damping of power system oscillations and transient stability. The IPFC performance is tested with PI controllers in comparison with fuzzy logic based controller under healthy and abnormal operating conditions. The IPFC fuzzy controller is design to coordinate two control inputs: change in voltage and change in capacitor voltage to improve the transient stability of the multimachine system. The Interline Power Flow Controller [IPFC] with fuzzy logic controller is designed with simple fuzzy rules to coordinate the additional damping signal. The proposed controller for IPFC is able to achieve improved designed performance of the power system. Digital simulations are carried out in MATLAB environment.
Comparison of Multi-Line Power Flow Control using Unified power flow controller (UPFC) and Interline Power Flow Controller (IPFC) in Power Transmission Systems  [PDF]
SUNIL KUMAR JILLEDI
International Journal of Engineering Science and Technology , 2011,
Abstract: The Unified power flow controller (UPFC) and Interline power flow controller (IPFC) are two latest generation flexible AC transmission systems (FACTS) controller used to control power flows ofmultiple transmission lines. This paper presents a mathematical model of UPFC and IPFC, termed as power injection model (PIM). This model is incorporated in Newton- Raphson (NR) power flow algorithmto study the power flow control in transmission lines in which UPFC and IPFC is placed and power flows are compared. A program in MATLAB has been written in order to extend conventional NR algorithmbased on this model. Numerical results are carried out on a standard 2 machine 5 bus system. The results are seen with our incoperation of any FACTS device and it has been compared with incorporation ofUPFC and IPFC are compared in terms of voltages, active and reactive power flows to demonstrate the performance of the IPFC model.
Controller Design and Stabilization and for a Class of Bilinear System  [PDF]
Ming-Ying Hsiao,Chi-Hua Liu,Shun-Hung Tsai
Information Technology Journal , 2010,
Abstract: This study presents a bilinear control scheme for a class of bilinear system. A controller is proposed to globally stabilize the bilinear system. Then, the stabilization condition is derived to guarantee the stabilizability of the control system in terms of Linear Matrix Inequalities (LMIs). Finally, a numerical example is utilized to demonstrate the feasibility and effectiveness of the proposed control scheme.
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