Quantifying Stability in Inverter-based Weak Grids in the Presence of Synchronous Condensers

Abstract

The high penetration of renewable energy resources integrated via power electronic inverters in weak and low-inertia grids is introducing new challenges to power systems. Inverter-based resources (IBRs) do not have native inertia similar to fossil-fuel-based generators and can cause sustained oscillations and instability. Synchronous Condensers (SynCons) are considered as a reborn technology to provide a solution for system strengthening and inertia supporting in IBR-dominant power systems. Although SynCons are a well-known technology, additional assessment for analyzing the stability of a weak grid with a high penetration of renewable resources in the presence of SynCons is required. This paper proposes a quantitative index for the stability analysis of a system, which includes black-boxed IBRs and SynCon. The proposed index is stemmed from impedance-based stability analysis. In this paper, the impact of a SynCon on the proposed stability index is evaluated in a single-machine infinite-bus system, and its accuracy is also verified in an IEEE 39-bus system. Additionally, the findings are verified using time-domain simulation tests in PSCAD/EMTDC software.