Abstract:
Doubly-fed wind farm often interacts with the power grid, leading to sub/super-synchronous oscillations. To address the issue of limited adaptability in suppressing these oscillations using impedance reshaping methods, this paper proposes an impedance reshaping method based on a static var generator (SVG)-additional current feedback control. The virtual impedance established by this method is correlated with the impedance characteristics of the wind farm, providing greater flexibility compared with fixed virtual impedance obtained through modeling and analytical design. Initially, the virtual impedance formulation, incorporating the SVG and wind farm grid-connected impedance models, is derived. Subsequently, the effectiveness of the proposed method and the impact of impedance reshaping control parameters on the suppression performance are analyzed based on impedance frequency characteristics. Finally, based on the grid-connected model of a doubly-fed wind farm in Qinghai Province, an electromagnetic transient simulation model is developed in PSCAD/EMTDC. The simulation results demonstrate that the proposed method achieves impedance reshaping for the wind farm under different oscillation conditions, effectively suppressing sub/super-synchronous oscillations in the wind farm.