Optimal Load Shedding for Voltage Stability Enhancement by Ant Colony Optimization

Voltage stability has become a serious treat of modern power system operation nowadays. To tackle this problem properly, load shedding is one of the effective countermeasures. However, its consequences might result in huge technical and economic losses. Therefore, this control measure should be optimally and carefully carried out. This paper proposes an ant colony optimization (ACO) based algorithm for solving the optimal load shedding problem. Two principal concerns of the problem are addressed. The appropriate load buses for the shedding are identified by sensitivities of voltage stability margin with respect to the load change at different buses. Then, the amount of load shedding at each bus is determined by applying ACO to solve a nonlinear optimization problem formulated in the optimal power flow framework. The performance of the proposed ACO based method is illustrated with a critical operating condition of the IEEE 30-bus test system.