Ranking power system contingencies for real-time assessment of voltage stability based on PMU data

Voltage stability has been one of the main challenges for power system operators in recent years. The ranking of contingencies is one of the practical factors in assessing voltage stability. Therefore, the importance of maintaining grid stability necessitates the real-time assessment of voltage stability to protect the system from the risk of instability, and contingency ranking provides a list of essential and critical contingencies in terms of their impact on the network for real-time use. In this paper, a new index for classifying contingencies is presented, which is defined based on the voltage deviation and phase angle of the buses and PMU data. The proposed index has been tested on the IEEE 30-bus network. First, using this index, a contingency study was performed in 1000 operating points, and in the second stage, the results of these studies were compared with a random operation point. Comparing the results obtained from the proposed index with other available indices shows its proper performance for ranking and screening possible contingencies in power systems.