A review of automatic contingency selection algorithms for online security analysis

An essential aspect of modern power system security assessment is the consideration of any contingencies which may arise due, for example, to planned or unplanned outages of lines, and which may cause system overloads. For power systems comprising of several hundred lines, it is impractical to examine all possible contingencies. Therefore, the system engineer makes a judgement, based on intuition and experience, and ranks contingencies in order of importance. An automatic contingency selection algorithm can assist this process of security assessment by providing an objective criterion to select the most critical contingencies in a given system state and to limit the number of contingencies included in this assessment. The author presents a critical assessment of automatic contingency selection methods as reported in the literature, and identifies the general requirements of automatic contingency selection algorithms in the real-time monitoring and control of power systems