Comparative Study of GFM-grid and GFL-grid in Islanded Operation

Abstract

Global activity for a sustainable society has encouraged the transformation of the power system from synchronous generator-based generation to a massive integration of variable renewable energy (VRE) generation interfaced by power electronic converters. This transformation comes with stability concerns such as low-Nadir and a high rate of change of frequency (RoCoF). To increase the stability of grid-connected inverters, grid-following (GFL) and grid-forming inverter (GFM) control have been designed to behave like synchronous generators. However, for stable operations of grid forming and grid following inverters, inertia, damping, and frequency restoration control are necessary. This paper evaluates the comparison of the GFM grid and GFL grid in islanded operation. The control of the GFL and GFM grid is evaluated for a 100% integration of VRE through GFL and GFM based inverters. The simulation results show that the GFM-grid is more stable than the GFL-grid. The result also revealed that GFM can maintain a stable operation with 100% integration of VRE.