Analysis of Angular Threshold Criteria for Transient Instability Identification in Uncertain Power Systems

This paper addresses the problem of finding a threshold (critical value of rotor angle) for the identification of transient instability by the sole use of the information on rotor angles. Several threshold values for rotor angles have been used in the past without a clear agreement on a standard value. In this paper a probabilistic approach to the problem is proposed, so that for any network a threshold can be defined based on set accuracy, while at the same time minimizing the instability identification time. Results demonstrate that highly accurate robust rotor angle thresholds can be found, even for highly uncertain power networks with a high penetration of Renewable Energy Sources (RES).