Comparison of Virtual Inertia Support in GFM Inverter-Based Resources with Different DC Sources

The modern electric power system is currently undergoing significant changes in its generation structure, substituting synchronous machines with Inverter-Based Resources (IBRs). This shift reduces the availability of rotating masses, challenging the stability of the power system due to the resulting decrease in grid inertia. Virtual Synchronous Generator (VSG) based Grid-forming (GFM) addresses these stability concerns. However, to the best of the authors' knowledge, a comprehensive analysis of virtual inertia provision for modeling the DC side with different sources has not yet been provided. This paper presents a review of DC side modeling considering three sources: an ideal DC source model, a battery model, and finally a wind turbine model. Case studies have been implemented within the MATLAB/Simulink environment which are illustrated and evaluated in terms of the Rate of Change of Frequency (RoCoF) and the frequency nadir. Finally, the IBRs modeled with these three different DC sources are compared with a Synchronous Generator (SG) of equivalent size and inertia values to assess the synthetic inertia against the inertia of the SG.