Stability boundary analysis of grid-forming and grid-following inverters

Stability issues and oscillations associated with inverter-based resources (IBRs) are of increasing concern in inverter-dominated power systems. This study explores the stability boundary of grid-following (GFL) and grid-forming (GFM) inverters and performs a sensitivity analysis for the most relevant control and grid parameters. A stability boundary tracking (SBT) algorithm is proposed, which can identify the stability boundary relating up to three parameters of interest for both GFL and GFM inverters. This boundary is then illustrated as two-dimensional stability curve or three-dimensional stability surface to facilitate understanding the impact of certain parameters on the stability margin. A comprehensive sensitivity analysis of different controller parameters as well as power factor and line R/X ratio draws parallels on their impact to GFL and GFM stability.