Influence Mechanism and VPSS Method of VSG for Low-Frequency Oscillation of Power System

Virtual synchronous generator (VSG) can not only enhances the inertia of the grid, but also introduces the oscillation characteristics of SG, which is easy to interact with the power angle of SG in the grid, and even produces low-frequency oscillation (LFO). This paper takes the single machine infinite system with VSG as the research object. Firstly, the model is linearized, and the influence path of VSG on LFO of SG is analyzed. To reduce the negative damping torque provided by VSG to SG through this path, a virtual power system stabilizer (VPSS) is proposed and the controller parameters are adjusted according to the phase compensation method. Finally, the effectiveness of VPSS is verified by modal analysis and simulation comparison.