The increasing penetration of renewable energy resources has raised concerns about voltage response characteristics and dynamic stability in weak grid conditions. Conventional grid strength indices, such as SCR, have limitations in capturing these dynamic characteristics. This paper evaluates voltage stability from a grid robustness perspective by combining static robustness indices with time-domain dynamic analysis. SCR, ESCR, WSCR, and SCRIF are used to identify vulnerable buses, and their effectiveness is validated through time-domain dynamic simulations. Results show that low-SCRIF buses exhibit poorly damped voltage responses and higher sensitivity to controller parameters. In addition, the effectiveness of STATCOM-based voltage support and POD control is demonstrated, showing improved voltage response and damping characteristics in weak-grid conditions.
Lee et al. (Fri,) studied this question.