The ongoing energy transition presents a range of challenges, from long-term planning to short-term power system stability. One key issue is the increasing penetration of inverter-based resources, particularly as synchronous generators are phased out. Grid-forming inverters offer a promising solution to this challenge, as they can replace traditional generators and provide grid-forming capabilities. However, their dynamic behavior differs in important ways, especially regarding their limited overcurrent capability when cost-effective designs are considered. As a result, grid codes must evolve to reflect these differences.

Like all grid-connected devices, grid-forming inverters must comply with grid codes to ensure stable power system operation. This paper focuses on the Low Voltage Ride-Through (LVRT) requirements specified by RTE (Réseau de Transport d'Électricité). We present an LVRT strategy for a grid-forming inverter and evaluate its compliance with the relevant grid code. The proposed control approach is based on the Virtual Synchronous Machine concept and does not rely on an underlying current control loop. Instead, current limitation is achieved through voltage limitation within the proposed scheme. Crucially, the inverter maintains its grid-forming function even during fault conditions.

The LVRT requirement specifies constraints on current rise time at fault initiation and on active power recovery following fault clearance. It also assesses the ratio of active to reactive power during the fault. To validate our approach, we perform EMT simulations in MATLAB/Simulink, demonstrating the effectiveness of the proposed method.