Design of a Reduced-Order WADC for Wind Turbine System-Integrated Power System

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.