Optimal Transmission Overloads Mitigation Following Disturbances in Power Systems

A system disturbance can cause severe ex-ceedances of the power system operating limits in which the transmission network overloads, if not being timely mitigated, can initiate cascading failures. So, an optimal and efficient postevent overload mitigation (PEOM) tool is necessary. However, research in the postevent mitigation is relatively limited as compared to that for the normal state and pre-event actions. Some existing dispatch methods consider the postcontingency scenario, but they do not fully address the postevent security and may lead to security issues such as power imbalance or violations of network security criterion. To address these issues and to improve the mitigation efficiency, this paper proposes a PEOM tool. PEOM implements a time-optimal load shedding for managing the power imbalance, ensures the time-dependent network security during the mitigation time period, and enhances the efficiency by prioritizing the mitigations. The simulations on the IEEE 118-bus and 2383-bus systems verify the effectiveness and efficiency of PEOM.