Transient Stability Enhancement of Inverter-based Resources with Virtual Synchronous Generator on Active Power Control Loop

This paper develops the transient stability enhancement of the inverter-based resources (IBRs) with the virtual synchronous generator (VSG) control employed. Firstly, based on the large-signal model, the instability phenomenon of the VSG control during voltage dips is fully analyzed. It is found that the frequency deviation Ao in the active power control loop (APCL) of VSG is always positive when the VSG is transiently unstable. Then, for guaranteeing stronger transient stability, an additional integral controller with the frequency deviation is added to the APCL in the VSG control. Moreover, a large-signal model of the proposed strategy is established. Then, the phase portraits with an integral controller in the APCL disabled/enabled are presented. It is seen that the improved control strategy has better transient stability under voltage dips. Finally, the simulation results verify the effectiveness of the proposed method.