High-Frequency Oscillation Analysis and Suppression Method for PV Power Generation System Equipped with Grid-Forming SVG

The high-frequency oscillation (HFO) occurred in the photovoltaic (PV) power generation station equipped with grid-forming (GFM) static var generator (SVG) is threatening the reliability of power system. This kind of HFO is generated by the interaction of negative resistance characteristic GFM, PV branch and inductive grid, while the existing analysis ignored the impact of the GFM SVG. To analyze the impact of GFM SVG on this kind of HFO occurring in PV power generation station equipped with GFM SVG, this paper establishes the PV power generation system's impedance model. Then, the impact of key GFM SVG parameters on the power generation system's high-frequency impedance characteristics is discussed. Further, to damp the HFO, an impedance reshaping strategy for GFM SVG based on attaching an additional current feedback control is proposed. The additional control can provide damping for the whole system so that the HFO can be suppressed. Finally, simulation results verify the stability impact analysis and the efficacy of the suppression strategy.