Voltage Fluctuation Suppression Strategy for Power Grid Based on Equivalent Doubly Fed Wind Farm Cooperative Static Var Generator

In allusion to the problems of grid voltage fluctuation after a grid-connected doubly-fed wind turbine, a large amount of the modeling calculation, and the complex frequency coupling relationship of traditional simulation analysis method, a grid voltage stability cooperative control method based on equivalent doubly-fed wind farm cooperative static reactive power generator (abbr. SVG) was proposed. Firstly, a two-step equivalent modeling method based on K-means clustering was proposed according to the clustering phenomenon of wind farm power characteristics, and the maximum reactive power compensation capabilities of stator side and grid side converters in double-fed induction generators (abbr. DFIG) were analyzed and defined. Secondly, to address the issue of insufficient support capability of SVG to the voltage at wind farm connecting points in the case of a power grid disturbance, a DFIG collaborative SVG power grid voltage fluctuation suppression strategy for different voltage fluctuation levels, which makes full use of the reactive power reserve of DFIG inside the wind farm station, and adds a delay link in the voltage recovery process to ensure voltage stability, was proposed. Finally, the effectiveness of the proposed collaborative control strategy in improving the voltage fluctuation at the wind farm connecting points was verified through simulation.