Simplified damping analysis and suppression method for low-frequency oscillation introduced by virtual synchronous generator

Similar to synchronous generators (SGs), the phenomenon of low-frequency oscillation (LFO) may occur when virtual synchronous generator (VSG) is involved in power grid, thereby negatively affecting the stability of the power system. In this paper, the oscillation mechanism of the power system composed of a VSG and infinite grid (single-VSG infinite-bus system) is analyzed, the conditions for the occurrence of LFO are unveiled, and a simplified damping selection method to suppress the LFO is provided, considering the adjustable damping of VSG. First, a small-signal model of the single-VSG infinite-bus system is established. The order of this system model is reduced using the damping torque analysis. Then, the mechanism of LFO under various dampings is analyzed. On this basis, a reasonable selection method of damping is drawn. The range of damping, where LFO converges, can be determined and the appropriate damping coefficient can be selected using this method. Finally, the effectiveness of the proposed method is verified by simulations and experiments.