Transient Stability Analysis and Improvement of Multiparalleled Virtual Synchronous Generators Grid-Connected System

The interaction between multiple virtual synchronous generators (VSGs) has a nonnegligible impact on the transient stability of the multiparalleled VSG grid-connected (MPVGC) system and may even cause a large number of VSGs to undergo transient instability successively. The existing research on the transient stability of VSG focuses on the single VSG grid-connected system, and it is difficult to extend to the transient stability analysis of the MPVGC system. In response to this problem, this article establishes the transient mathematical model of the MPVGC system and compares it with the single VSG grid-connected system. It is found that the interaction between multiple VSGs simultaneously affects the equilibrium point state and transient synchronization process of the MPVGC system. Then, the equilibrium point state of the MPVGC system is quantitatively assessed based on the Newton–Raphson method, and the influence mechanism of the interaction between multiple VSGs on the transient stability of the MPVGC system is revealed. In terms of improving the transient stability of the MPVGC system, an active power distribution method that minimizes the risk of transient instability is proposed to optimize the power angle distribution characteristics of each VSG. Finally, simulations and experimental results verify the correctness of the theoretical analysis and the effectiveness of the proposed method under different working conditions.