Symmetrical Components Extraction for Grid-Forming Voltage Source Converters

Fast and accurate detection of symmetrical components is critical for ride-through of asymmetrical faults in grid-forming (GFM) inverter based resources (IBRs). Compared to their grid-following (GFL) counterparts, faster and stable detection of symmetrical components is desired for GFM IBRs due to their more stringent fault ride-through requirements. In this work, five different time-domain approaches for symmetrical components extraction are evaluated from transient response time, accuracy, and digital implementation perspective. Fundamental grid frequency adaptive implementations of these methods are considered, where their output accuracy is compared at different sampling rates. Based on simulation and experimental results, guidelines are presented for preferred implementation strategies at high versus low and fixed versus variable sampling rates.