Small-Signal Stability Analysis of Low-Inertia Power Grids with Inverter-Based Resources and Synchronous Condensers
Lizhi Ding, Xiaonan Lu, Jin Tan
Abstract
With the potential environmental impacts of conventional fossil fuels and the technological advances of grid-interactive power electronics, inverter-based resources (IBRs) are playing a crucial role in modern power grids for decarbonization. Several pathways to gradually transition to a 100% renewable power grid are still under discussion, including providing grid inertia by converting the retired synchronous generators into synchronous condensers (SCs) or operating a 100% IBR grid by implementing grid-forming (GFM) inverters. As we move toward 100% renewables, ensuring grid stability is necessary; therefore, understanding the fundamental dynamic stability characteristics of an IBR-dominated grid becomes essential. For this purpose, a generic, small-signal grid model with the detailed control schemes of both SCs and IBRs has been developed. Specifically, the grid-following (GFL) control mode with and without droop control and GFM control mode are modeled separately and compared to understand the main differences and their impact on grid stability in terms of induced oscillation modes and critical control parameters.