Dynamic stability is a major concern in operating power systems with high levels of inverter-based resources (IBRs). Dynamic stability problems in IBR grids manifest as oscillations or control interactions that are observed either locally between a few IBRs or span a wider network involving tens to hundreds of IBRs. It is quite challenging to evaluate the stability of IBR grids because of fast, complex, and non-standardized controls of IBRs as well as unavailability of their open-box models from vendors. This webinar will review impedance-based methods for stability analysis of IBR grids. It will also present a PSCAD-based impedance scan software tool and an impedance measurement system developed at NREL for analyzing the stability of IBR grids. Case studies to demonstrate the capabilities of these tools to answer questions such as “which IBRs are causing oscillations?” or “how much grid-forming capacity is needed in a system?” will be presented.
- Shahil Shah, Senior Engineer, NREL