A detailed study on Transient Stability Enhancement of Grid-Forming Inverters

Abstract

The integration of the weak grids along with the clean energy that comes from the natural resources requires stable interconnection of Voltage-Source Inverters (VSIs) with weak grids. During severe voltage sags, weak grid integrated VSIs may fail synchronization with the grid.These inverters' transient stability under severe grid disruptions is weak and significantly different from that of synchronous machines. To prevent the side band oscillations in the weak grids, the emerging inverters based on grid-forming are preferred over the grid following inverters in the weak grids. These inverters synchronise with the grid using a power-based synchronisation technique in order to prevent the instability brought on by a typical Phase Locked Loop in weak AC grids. This study presents a comprehensive review of the transient stability improvement of Grid-Forming VSIs.