Interoperability of Grid-Forming Inverters in Microgrids During Faults

As inverter-based resources increasingly dominate modern power systems, including microgrids, ensuring stable and reliable operation during normal and abnormal operation becomes essential. This paper investigates the interoperability of grid-forming inverters in microgrids by examining the behavior of inverters operating under combined control methods and fault-ride through (FRT) strategies when interconnected during symmetrical fault events. A dynamic microgrid model is developed, incorporating grid-forming primary controls (droop and virtual synchronous generator (VSG)) and FRT mechanisms (current magnitude saturation (CMS) and virtual impedance (VI)). The study compares these control methods under symmetrical faults, highlighting their impact on system stability, fault recovery, and power sharing. Results show that primary control and FRT methods influence system behavior during normal operation and during and after faults, with more stable performance observed in homogeneous systems. Droop control with CMS outperforms VSG with VI for the specific study case.