Fault Ride-Through Analysis of Current- and Voltage-Source Models of Grid Supporting Inverter-Based Microgrid

Withstanding fault is a crucial technical challenge for inverter-based systems. Evolving grid codes require microgrids to possess fault ride-through (FRT) capabilities and support the grid voltage recovery. The traditional grid forming and grid feeding models lack such abilities. Consequently, this article enhanced these traditional models with droop control-virtual impedance and secondary power reference generation to form two models of a grid-supporting system. The first is a current source for grid feeding control, and the second is regulated as a voltage source for grid forming control. The result presents grid fault impact and FRT compliance in the proposed and traditional systems. Furthermore, the fault current curtailment and FRT improvement of the virtual impedances in the grid forming control were investigated within the MATLAB/Simulink environment. These proposed systems achieved FRT under a dynamic period and reverted to appropriate power delivery control under a static period.