Congestion Management Using Optimal Transmission Switching

In this paper, a multiobjective-based congestion management (CM) methodology is proposed using the optimal transmission switching (OTS) strategies considering the minimization of the total operating cost and the maximization of probabilistic reliability as two conflicting objectives. To improve the efficiency of the transmission network, this paper considers the possibility of changing the topology of the transmission system using the transmission switching strategy. The OTS can increase the economic efficiency of power dispatch with the existing infrastructure. The objective of OTS is to find the most influential lines as candidate lines for the disconnection. System operators can change the network topology to increase the transfer capacity, to improve voltage profiles, and also to improve the reliability of the power system. In this paper, the loss of load probability reliability index is used to indicate the probability that an electrical power system is not able to serve the prescribed load within the concerned period of time. Here, the transmission lines that should be switched are determined by using the security-constrained ac optimal power flow. The proposed optimization problem is solved using the hybrid of evolutionary and stochastic programming approaches. The output of the proposed OTS is to find the transmission lines that have to be switched so that the congestion in the system can be relieved. A multiobjective optimization approach is used to generate the Pareto optimal solutions. The suitability and effectiveness of the proposed CM approach have been examined on IEEE 30- and 300-bus test systems.