Security monitoring against voltage collapse through ant colony system

Modern power systems are operated much closer to their stability limits owing to economical and environmental constraints. Deregulated operation has increased variability of loading patterns many folds compared to limited operating scenarios of vertically integrated power system. In the existing operational environment, online monitoring against possible voltage collapse has become all the more important. In the reported work voltage collapse margin (active and reactive) is estimated using ant colony system algorithm. The technique is inspired by foraging habits of ants. It has an edge over the existing methods that it can optimize many independent parameters simultaneously. To evaluate the performance of this proposed method, IEEE 30-bus and a practical 75-bus system is considered. Results obtained from the study and conclusions drawn are also presented.