POWER SYSTEM CONTINGENCY RANKING BASED ON SHORT-TERM VOLTAGE STABILITY INDICES

This paper presents a methodology to identify critical contingencies that produce short-term voltage stability problems (STVS). The proposed methodology classifies the state of the power system for each contingency, assessing the voltage stability of the post-contingency dynamic response from the calculation of the maximal Lyapunov exponent (MLE) and dynamic voltage indices at each bus and the whole system. In order to determine the critical contingencies, the values of the indices and the results of the classification of the post-contingency state are statistically analysed. The methodology is tested in the New England 39-bus system, obtaining satisfactory results in relation to the identification not only of the most critical contingencies but also of vulnerable buses to voltage instability. New contributions of this work are the contingency classification methodology, the algorithm for calculating dynamic indices and the method of classification of the operating state as a function of the STVS problem magnitude.