Robust thyristor-controlled series capacitor controller design based on linear matrix inequality for a multi-machine power system

Abstract

Power system stabilizing control has an important role in maintaining synchronism in power systems during major disturbances resulting from sudden changes of load and configuration. The thyristor-controlled series capacitor (TCSC) is one of the representative devices in flexible AC transmission systems. In this paper, robust TCSC controllers are applied to suppress disturbances in realistic power systems. H ∞ control is adopted as the methodology of the robust controller design along with a linear matrix inequality (LMI), which solves the Lyapunov inequality without the weighting coefficients used in other control theories. In the proposed design, load changes are treated as a system uncertainty in the LMI approach. The proposed LMI-based approach is shown to be effective in the design of TCSC controllers to enhance robustness and response by simulations on a test system.