Ant Colony Optimization for Maximum Loadability Search in Voltage Control Study

Several blackout occurrences in many part of the world had indicated the importance of voltage stability studies. These events could be caused by line or generator outages, stressed condition, change of loads and load shedding. The occurrence of voltage collapse is very much dependent upon the maximum permissible load that can be supported at a particular load bus. Any attempt to increase the load beyond this point could force the entire system into instability, leading to voltage collapse. This would indicate that the power system physically could not support the amount of the connected load. This paper presents the application of ant colony optimization (ACO) technique for searching the optimal point of maximum loadability point at a load bus. The optimal point identified using this technique in the off-line mode can assist the power system operators to perform pilot study prior to intended load increment in their transmission system. Comparative studies performed with respect to evolutionary programming (EP) and automatic voltage stability analysis (AVSA) algorithm had indicated the merit of the proposed technique. The capability of the developed ACO engine in solving the non-graphical optimization problems has been identified as the strength of the proposed technique.