Abstract: Contingency screening and ranking is one of the important components of on-line system security assessment which is done with the help of various computer softwares which employ the iterative load flow methods. The objective of this contingency screening and ranking is to quickly and accurately select a short list of critical contingencies from large potential contingencies and rank them according to their severity. To maintain security against voltage collapse, it is desirable to estimate the effect of the contingencies on the voltage stability. In general terms, the proposed procedure consists of obtaining the operating state and computing performance indices for each contingency of a predefined list. The contingencies are then ranked according to their performance indices. This study presents fuzzy approach to combine ranking of the performance indices and a new rank list is prepared. The proposed approach is tested on IEEE-14 bus test system and practical Indian 75-bus test system.
M. Kowsalya, K. K. Ray, Ranjeet Kumar and Raunak Rastogi, 2010. Fuzzy Based Multi Criteria Contingency Ranking for Voltage Stability Assessment. International Journal of Soft Computing, 5: 185-193.