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The impact of wind turbine system (WTS) on power system stability is elaborately addressed in the literature. However, low-frequency oscillations, especially inter-area oscillations (IAOs) can be adversely affected due to their intermittent nature. This article proposes a wide-area damping controller (WADC) for WTS-integrated power system to damp IAOs effectively. The feedback signals (linear combination of the system states) are directly measurable from phasor measurement units. Therefore a reduced-order estimator is proposed instead of a full-order estimator to design the WADC. Furthermore, to select appropriate feedback signals for WADC design, combined geometric measure and modal decomposition techniques are utilized. The overall procedure to design the reduced-order WADC includes feedback signal selection, state feedback formulation using modal transformation approach, and reduced-order estimator design using loop transfer recovery procedure. Moreover, the WADC parameters are selected considering operating point uncertainties and variable time delays in feedback signals. Performance of the proposed WADC is validated on WTS-integrated 16-machine, 68-bus system. The simulation results show that the proposed WADC gives robust performance over broad operating scenarios. [ABSTRACT FROM AUTHOR]

Damping of low-frequency oscillations (LFOs) has become a critical challenge in modern power system. Since interarea LFO modes are associated with power oscillation, therefore, proper modulation of power through energy capacitor system (ECS) can be a competent way to conserve system stability. In this article, modeling of grid-connected ECS unit is explained thoroughly. Further to provide adequate damping to critical LFO modes, a linear quadratic Gaussian (LQG) based optimal $ H_{2}$ wide-area damping controller (WADC) is proposed for ECS integrated power grid. The parameters of the proposed WADC are tuned by accelerated particle swarm optimization (APSO) technique. Furthermore, to select the proper wide-area signals for controller design, geometric approach is adopted. The efficacy of proposed methodology has been tested on large power systems containing multiple interarea modes viz. 10-machine, 39-bus system and 16-machine, 68-bus system. Simulation studies demonstrated the capability of proposed WADC to adequately damp the multiple interarea modes simultaneously. Moreover, it also provides robust performance for operating point uncertainties (load variation, permanent outage of transmission lines, etc.) and variable time delays in feedback signals. [ABSTRACT FROM AUTHOR]