Aiming at the problems of insufficient reactive voltage support capability of the grid-forming inverter

poor power angle stability of the grid-forming system

and limited current carrying capability of power electronic devices during three-phase symmetrical short-circuit faults in the grid

this paper proposes a grid-forming inverter transient control strategy considering of the power angle stabilization and current limitation of faults. Firstly

based on the traditional second-order grid-forming inverter control strategy

the first-order transient voltage equation is introduced

the third-order grid-forming (active-support type) inverter transient control strategy is constructed

and the transient voltage support capability of the active-support type inverter is analyzed; secondly

the power-angle stability of the system is improved by compensating the imbalance power during the transient period in the active control link

and the fault current is limited by adjusting the voltage command value to limit the fault current; finally

the transient control trigger coefficient Kon is designed to solve the coordination problem between transient power angle and short-circuit current control. The effectiveness of the proposed transient control strategy in dealing with three symmetrical short-circuit faults in the power grid is verified by constructing a simulation model.