Determination and Verification of Real-Time Transient Stability of Jeju System According to Increase in Renewable Energy

The increasing integration of resources with limited flexibility, such as solar power, electric vehicles (EVs), and other renewable energy sources, has raised significant concerns regarding power system stability. The stability of power systems is constantly threatened, particularly in cases where renewable energy is supplied to areas near generators, as transmission capacity constraints may lead to severe stability issues. The impact of renewable energy integration on system stability can be analyzed using transient stability and phase-angle stability theories. This study proposes a methodology to quantify the effects of renewable energy integration on transient stability. A power-phase angle curve is plotted using the Thevenin impedance calculation technique, and an improved equal-area method index is utilized to evaluate transient stability issues caused by renewable energy penetration. The proposed transient stability discrimination index (TSDI) is used to assess system stability in real-time conditions. Simulation results demonstrate that the proposed method achieves an accuracy of over 90% in ranking transient stability compared to conventional offline stability analysis. Furthermore, a correlation coefficient of 0.85 is observed between the proposed TSDI and the existing wide-area voltage stability index (WAVI), confirming the reliability of the method. These findings suggest that, when real-time Phasor Measurement Unit (PMU) data are available, the proposed approach can be effectively applied to practical power systems for enhanced stability assessment.