Fuzzy Approach to Contingency Ranking

The contingencies contribute to overloading of network branches and unsatisfactory voltages, which may lead to problems of stability/voltage collapse. The most important task in security analysis is the problem of identifying the critical contingencies from a large list of credible contingencies and rank them according to their severity. This paper presents fuzzy approach for ranking the contingencies using composite-index. The fuzzy approach uses post-contingent bus-voltage profiles and Lindex used as static voltage collapse proximity indicator to compute voltage stability margin. The composite index based on severity of bus voltage profiles and L-index is used to evaluate contingency ranking. The proposed approach is tested on IEEE-30 bus system.