Voltage Stability Assessment Based on Modified Line Voltage Stability Index in the Presence of Renewable Energy Integration and Credible Contingencies

ABSTRACT Modern power systems are significantly impacted by unpredictable load fluctuations, renewable energy integration, and an increasing number of outages—operational scenarios that have the potential to cause voltage instability and collapse. This necessitates near real‐time monitoring and control by operators, enabling the identification of critical lines or vulnerable buses operating close to their stability limits. This study proposes a modified line voltage stability index (MLVSI) to enhance the accuracy and computational speed of voltage stability assessment (VSA) adapted to diverse operating scenarios. The index incorporates active and reactive power, the angular difference between sending end and receiving end bus voltages, and line impedance. Using the IEEE 57‐bus test system, the proposed index was validated against existing stability indices—line stability index (Lmn), modern voltage stability index (MVSI), and novel collapse prediction index (NCPI)—by comparing accuracy and computation time under various operational scenarios. Results indicate that MLVSI provides higher accuracy and faster detection, particularly under extreme operating conditions. For example, compared with the NCPI, the MLVSI achieved a 4.8% improvement in accuracy and reduced the computation time by 0.07–0.103 s on different operating scenarios. The adaptability of MLVSI to diverse scenarios underscores its potential for broad application in the assessment of voltage stability.