Enhancing Frequency Stability of Low-Inertia Systems Using Virtual Synchronous Generator-Controlled Grid-Forming Inverter

The increasing penetration of renewable energy sources (RESs) has changed traditional power systems, which relied on synchronous generators (SGs), into low-inertia systems mainly supplied by inverter-based resources. This shift reduces system inertia and creates challenges in maintaining grid stability. Virtual synchronous generator (VSG) control has developed into an effective solution by providing virtual inertia and emulating the dynamic behavior of SGs. This study proposes a VSG control approach for grid-forming (GFM) inverters and evaluates it by using the IEEE 9-bus test system. The performance of the VSG is assessed under various conditions, including sudden load increases and reductions in control parameters. Results demonstrate that VSGs provide rapid frequency and voltage stabilization, compensating for the slower response of SGs. However, their fast response can result in a higher rate of change of frequency (ROCOF), which can activate protection devices unnecessarily. These results indicate the potential of VSG control in supporting RES integration and overcoming challenges in low-inertia systems.