A frequency domain model-based design of PSS and TCSC controller for damping the small signal oscillations in the power system

For improvement of the operation and control of the power system, the flexible AC transmission system devices are significantly used. This paper proposes a model-based frequency response matching technique for designing a lead-lag power system stabilizer and a thyristor controlled series capacitor controller to improve the small signal stability. The method relies on development of an appropriate reference model, based on the desired specifications that can be attainable by the system dynamics. The unknown controller parameters are obtained by the frequency response matching between the closed-loop control system and the reference model. The efficacy of the proposed controllers is examined on an unstable test power system taken from the literature. Improvement of the damping factor and the other performance indices shows robustness and effectiveness of the proposed controllers for stabilizing the power system oscillations in comparison with some design methods prevalent in the literature. It is illustrated through rigorous simulation that the proposed controller works successfully for stabilizing the power system over a wide unstable operating conditions and perturbed system models.