Robust control design for UPFC to improve damping of oscillation in distribution system by H2 method
ABSTRACT An industrial plant, such as power systems, always contains parametric uncertainties. In the design of a controller the uncertainties have to be considered. Otherwise, if the real plant differs from the assumed plant model, a controller designed based on classical controller design approaches may not ensure the stability of the overall system. In this paper design of robust control for the UPFC controllers including power - flow and DC voltage regulator, using a H2 design is presented. As an example, we have designed a case for the system to compare the proposed method with a conventional method (classical P-I controller). AS the results of the simulations, the validity of the proposed method has been confirmed.
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ABSTRACT: The author outlines the technical and economic factors which characterise the uniform, all solid-state power-flow controller approach for real-time controlled, flexible AC transmission systems. The unified power-flow controller in its general form can provide simultaneous, real-time control of all basic power system parameters (transmission voltage, impedance, and phase angle), or any combinations thereof, determining the transmitted power. The parameters selected for control can be changed without hardware alterations, e.g. the function of the controller can be changed from that of a phase-shifter to that of a series line compensator, or vice versa, with or without additional terminal voltage regulation and shunt VAr compensation, to adapt to particular short term contingencies or future system modificationsGeneration, Transmission and Distribution [see also IEE Proceedings-Generation, Transmission and Distribution], IEE Proceedings C 08/1992;
Conference Proceeding: Versatile control strategy of the unified power flow controller (UPFC)[show abstract] [hide abstract]
ABSTRACT: 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 is 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 paperElectrical and Computer Engineering, 2000 Canadian Conference on; 02/2000
Conference Proceeding: Application of a nonlinear PID controller on STATCOM with a differential tracker[show abstract] [hide abstract]
ABSTRACT: In this paper a nonlinear PID controller is suggested for damping the interarea power oscillation of interconnected power systems. A differential tracker is introduced to obtain a low-noise derivative of the controller input signal. The nonlinear PID controller is applied on STATCOM supplementary control. A computer program for transient and steady-state stability study has been developed based on the Power System Toolbox of MATLAB. Computer tests show clearly the effectiveness of the nonlinear PID controller and the good performance of the differential trackerEnergy Management and Power Delivery, 1998. Proceedings of EMPD '98. 1998 International Conference on; 04/1998