Recognition of critical “N-2” contingencies in power system using non-linear optimization

An efficient method is proposed to identify a set of critical lines in power system network, outage of which can cause serious blackout in the system. To recognize such set of critical lines a two stage methodology is presented. In the first stage criticality measure of all lines is computed in a single run thus providing an overall view of the system. In second stage the information of criticality of all lines is used to identify critical “N-2” contingencies. To Identify “N-2” contingencies the method does not require brute-force enumeration of all combination of line outages, only critical lines identified in the first stage are considered in second stage. The effectiveness of presented method is demonstrated on a small test system and standard IEEE-30 bus system. The algorithm is very fast and efficient to distinguish the highly critical lines in the power system and identifying severe multiple contingencies. Such fast algorithm can be very much useful for online identification of critical “N-2” contingencies.