A New Under Frequency Load Shedding Scheme for IEEE 39-Bus Test System with the Presence of Renewable Energy Sources

The increasing use of Renewable Energy Sources (RES) in power systems introduces challenges in maintaining stability and frequency. As reliance on these intermittent sources grows, power supply reliability becomes critical. Under Frequency Load Shedding (UFLS) is an emergency control action that restores power system balance by shedding part of the load when the frequency drops below a set threshold. This study evaluates UFLS’s role in ensuring a reliable power supply and preventing blackouts, especially with RES. Using ETAP software, simulations were conducted for two separation scenarios in three study cases using the "New England test system 39-node." The study assessed UFLS performance in traditional and RES-integrated systems. Results showed UFLS effectively prevents blackouts and restores frequency stability during imbalances. Additionally, the study analyzed RES’s impact on UFLS and designed an effective UFLS plan considering load amounts and frequency relay response times. These findings highlight RES’s effect on power system stability and underscore UFLS’s importance in maintaining frequency stability.