Inter-Area Oscillation Analysis of Power System Integrated with Virtual Synchronous Generators

Increasing integration of inverter-based resources (IBRs) brings new power system stability challenges. Virtual synchronous generator control-based IBRs (VSG-IBRs) are expected to take the role of some traditional SGs and reconstruct the future power system. Although VSG control imitates the main dynamics of SG, the impact of VSG-IBRs on power system stability can be different and thus worth a detailed study. In this paper, SGs in two test power systems are substituted by VSG-IBRs to investigate the impacts of VSG-IBR substitution locations, the control parameters, and the distributed or centralized substitution strategies on inter-area oscillations. The instability mechanism of inter-area oscillation as a type of low frequency oscillation (LFO) is first briefly discussed, and a selection and validation method of VSG-IBR substitution location is then proposed. The study indicates that the damping coefficient of the active power loop (D_pVSG) is crucial to system stability. Then, based on the proposed method, VSG-IBRs with properly designed D_pVSG are recommended to substitute SGs with higher participation factors (PFs) to provide more positive damping to the inter-area oscillation modes. In a large-scale system, the distributed substitution strategy contributes the positive damping of VSG-IBRs to more modes, thus further improving the system stability.