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This paper establishes the linearized Phillips-Heffron model of a power system equipped with UPFC and demonstrates the application of the model in analyzing the damping effect of the UPFC and designing UPFC based stabilizer to improve power system oscillation stability. A comprehensive approach to the design of UPFC based stabilizer (power flow control, DC-voltage regulator and damping controller) is presented. In this case, the multi-machine power system with UPFC is studied and an example of power system is presented. It is shown that the DC voltage contributes negative damping to power system oscillations, which is confirmed by both eigenvalue computation and nonlinear simulation. To counterattack the negative damping effect due to the DC voltage regulator, UPFC based stabilizer is designed and its effectiveness is demonstrated by both eigenvalue computation and nonlinear simulation. Then the effects of UPFC and PSS on power systems are compared. Simulation results show that the performance of UPFC based stabilizer on damping of power system is better than PSS. Key words: Phillips-heffron model, UPFC, stabilizer, PSS, INTRODUCTION The Unified Power Flow Controller (UPFC) is a FACTS device which can control power system parameters such as terminal voltage, line impedance and phase angle (1-2). The primary function [...]

New approach based on structured singular value ([mu]-synthesis) was proposed for the robust decentralized unified power flow controller (UPFC) design. To achieve decentralization, using the Schauder fixed point theorem the synthesis and analysis of multi-input multi-output (MIMO) control system translated into a set of equivalent multi-input single-output (MISO) control system. Power systems similar to other industrial plants contain different kinds of uncertainties which should be considered in controller design procedure. For this reason, the idea of [mu]-synthesis technique being used for designing of UPFC controllers. The proposed [mu]-based controller had a decentralized scheme and advantage of a decentralized controller design reduction in the controller complexity and suitability for practical implementation. The effectiveness of the proposed control strategy evaluated under operating conditions on damping of low frequency oscillations in comparison with the classical controller to demonstrate its robust performance through nonlinear time simulation and some performance indices. Key words: Unified power flow controller, decentralized control, [mu]-synthesis, Flexible Ac Transmission Systems (FACTS), robust control, structured singular value, INTRODUCTION In recent years, the fast progress in the field of power electronics has opened new opportunities for the power industry via utilization of the controllable FACTS devices such as [...]

Grid Computing is a promising infrastructure and technology that involves the integrated and collaborative use of Computers, networks, databases and scientific instruments owned and managed by multiple organizations. In this context our research primarily aims at developing an application framework for monitoring the Performance of Power Transmission and Distribution System using Grid Computing. Power Transmission and Distribution System of Electrical Network supplies power to millions of consumers. The demand for electrical energy is ever increasing. Today over 21% of the total electrical energy generated in India is lost in transmission and distribution. It is possible to bring down the distribution losses to the minimum level in India with the help of newer technological options in information technology called Grid Computing in the electrical power distribution sector which will enable better monitoring and control. By monitoring and controlling the parameters such as voltage, load, frequency and power factor in electrical power transmission and distribution systems the line loss will be reduced. When the Power factor is monitored using this Grid computing method, the Substations can maintain their norms by giving proper instructions to the operators dynamically to add the capacitor banks to maintain the power factor so that the line loss will be reduced and the revenue will automatically be increased. Key Words: Grid computing, Transmission and Distribution system, monitoring and control, Line loss, INTRODUCTION The Growth of the Internet, along with the availability of powerful computers and high-speed Networks as low-cost commodity components, is changing the way scientists and engineers do computing, and [...]