In this study a UPFC-based non-linear adaptive controller is proposed and designed to damp generates oscillations. The adaptive controller design is based on determination of control signal using a new linear quadratic pole placement control law and identification of power system parameters with a recursive least squares method with adaptive directional forgetting factor. A new model of UPFC has been introduced too. The simulation results show that the adaptive controller can damp power oscillation more effective than the conventional PID controller and it is not sensitive to the loading conditions and the changes in power system topology
The purpose of this paper is to present a novel combined design of the voltage source converter–high voltage direct current (VSC-HVDC) and the power system stabilizer (PSS) controllers to obtain a better dynamical response. The proposed technique is applied to enhance the damping of the power system low-frequency oscillations (LFOs) and results are compared with traditional design. A fuzzy logic controller is designed for PSS (FPSS). Then, a chaotic optimization algorithm, which has a strong ability for finding the most optimistic results, is employed, in presence of FPSS, to search for optimal VSC-HVDC output feedback controller parameters. Moreover, a singular value decomposition method is utilized to select the most effective damping control signal of the VSC-HVDC output feedback controllers. The novel proposed controllers are evaluated on an AC/DC power system. The simulation results demonstrate that the combined controllers have an excellent capability for damping power system LFOs and greatly enhance the dynamic stability of the power system. Also, the system performance analysis under different operating conditions and some performance indices show the effectiveness of the proposed controllers. The benefit of the suggested procedure is greatly improving the dynamic response of the system. In addition, the overshoots, undershoots and the settling times are dramatically reduced by applying the proposed method.
Abstract. Catastrophic failures in power grid due to maloperation of traditional backup protection system (e.g. third zone of distance relays) was one of the main causes of many cascade trips. This paper assess a new wide-area backup protection system (WABPS) based on phasor measurement units (PMU), to improve third zone of distance relays to avoid its mal-operation. Based on this assessment, phasor measurement units with high speed communication system such as fiber optic and using time transfer with GPS system have dynamic adjustment for reliable backup protection system to avoid mal-operation. The new backup protection system is based on phasor measurement units (PMU) obtained from studies on the IEEE 9 bus test system using Matlab Simulink. It can successfully distinguish between actual and virtual faults for interconnected lines
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