Frequency Response Analysis and Enhancement of Grid-Forming Wind Generation Systems

Grid-forming (GFM) wind generation systems (WGSs) can actively respond to the grid frequency change during disturbances. However, with increasing intensities of disturbances, the frequency response (FR) performance of GFM WGSs gradually becomes insufficient, resulting that grid frequency deviations are prone to exceeding pertinent thresholds. Due to the properties of GFM WGS building frequency and its interaction with the grid frequency, the FR mechanism is not yet clear, which poses a challenge to enhancing the FR performance of GFM WGSs. To this end, this paper analyzes the FR mechanism of GFM WGSs and proposes an FR enhancement control. Firstly, an FR model that can reflect the above frequency interaction is established. Then, the FR mechanism of GFM WGSs is analyzed from a physical perspective, including indirect and direct FR. Two corresponding FR enhancement paths are discovered: i) an indirect path based on adjusting the parameters of power-frequency loop in GFM control, and ii) a direct path based on adjusting the WGS power. Based on the direct path, a novel FR enhancement control is developed by promptly presetting power to correct the reference power of WGSs after disturbances. Finally, the superb FR enhancement effect of the proposed control is verified by experiments.