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 (DpVSG) is crucial to system stability. Then, based on the proposed method, VSG-IBRs with properly designed DpVSG 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.