Transient Stability Analysis and Enhancement of Grid-forming Inverters in the Presence of Energy Storage Systems

The transient stability (TS) of grid-forming inverters (GFMIs) during and subsequent to faults are focused. Firstly, an adaptive virtual resistor is proposed to mitigate post-fault oscillations of GFMIs. The study then concentrates on the TS of the synchronising loop of GFMIs, with the limited overcurrent capability of GFMI considered. It is then extended to investigating the TS of GFMI-GFLI systems. The study expands to radial multi-IBR networks. These studies provide insights into stability boundaries and instability mechanisms of GFMIs and their impacts on the connected network. Furthermore, several enhancing control solutions are proposed to improve the TS of GFMIs.