Transient Stability Analysis of Virtual Synchronous Generator Considering Current Limitation

As a grid-forming control strategy, virtual synchronous generator (VSG) has been widely applicated in distributed resources in recent years. Since VSG-based converters behave as voltage sources, which are sensitive to large disturbances, current limitation is necessary for the VSG to protect converters from overcurrent. However, the impacts of current limitation on the transient stability of VSG have not been comprehensively investigated in current studies. Accordingly, the impacts of different current limiting strategies on the transient stability of VSG are studied in this paper in detail. In particular, the dynamic behavior of the power angle of VSG under different output active power during the fault is investigated. In addition, the transient stability margin of VSG is evaluated by determining the critical clearing angle and the deceleration angle. Finally, the validity of the transient stability analysis of VSG considering current limitation is verified by simulations.