Graph theory based corrective control strategy during single line contingency

This paper presents a new Graph Theory based corrective control strategy to alleviate overloads of transmission lines, with the help of a local optimization concept. A Direct Acyclic Graph (DAG) technique for selection of participating generators and load buses with respect to a contingency is presented. Particle Swarm Optimization (PSO) technique has been employed for generator rescheduling and/or load shedding to the identified generators and loads, to bring back the system from abnormal to normal operating state. The effectiveness of the proposed approach is demonstrated for different contingency cases in IEEE 57 and modified IEEE 118 bus systems. The result shows that the proposed approach is computationally fast, reliable and efficient, in restoring the system to normal state after a contingency with minimal control actions.