Experimental Validation of Synchronous Compensators for Enhancing Grid-Following DFIGs

Abstract

Modern power systems are facing a drastic reduction in inertia and grid stiffness due to the massive integration of Inverter-Based Resources (IBRs). In this context, grid-following (GFL) converters relying on phase-locked loops (PLLs) are prone to instability and poor damping under weak grid conditions or sudden load changes. This paper presents an experimental validation of the interaction between synchronous generation, GFL converters, and synchronous compensators (SCs) within the LIDER Lab (Laboratory for Innovation and Development of Renewable Energies) environment. Small-signal stability analysis is combined with large-signal experimental tests. Experimental results confirm that the connection of a synchronous compensatornot only reduces the frequency nadir following load steps, but also significantly improves the damping of the frequency measured by the PLL, thereby mitigating the risk of loss of synchronism.