Modified Droop-based Fault Current Control for Grid Forming Converter during Network Faults

Reliability and stability of a power system are important aspects for the recent increase in inverter-based resources. Grid forming (GFM) converters have shown to be suitable solution as they can replicate the performance of a synchronous generator. However, since these converters have a characteristic of controlled voltage source behind impedance, they experience overcurrent during network faults. Recent research works have investigated the current limitation of GFM converters, however there is still a gap in the area. In this paper, a droop based GFM control is adopted, and its control is modified to support fault-ride through (FRT) strategy. An enhanced FRT method that switches to current control is implemented that improves the performance of GFM converter. The performance of the proposed technique is verified and validated through simulations in PSCAD/EMTDC.