Transient Characteristics Assessment and Enhancement of Grid-Forming Virtual Synchronous Generators During Three-Phase Short Circuit Fault of Grid
The significant disadvantage of virtual synchronous generators(VSG)compared to synchronous generators is that there is no overcurrent capacity,which can damage the inverter components in the event of failure.Therefore,the transient problem of VSG under three-phase short-circuit fault of grid is studied comprehensively considering voltage control and current limitation of power angle stability.By increasing virtual impedance and changing active power reference value,the output current of VSG is limited to keep the power angle of VSG stable.In addition,the transient process stages of VSG three-phase short circuit fault are refined and defined,and the regulation range of virtual inductance and power reference value in each stage is studied,and the control strategy to improve the transient characteristics of VSG short-circuit fault is proposed.