Mitigation of Cascading Outages Using a Dynamic Interaction Graph-Based Optimal Power Flow Model

Online decision support for effective mitigation actions against propagating cascading outages in a power grid still poses a big challenge to grid operators. This paper proposes an online mitigation strategy against cascading outages using an optimal power flow model based on a dynamic interaction graph of the power grid. For a given power grid, its interaction graph model proposed in recent literature is composed of components and links that have large contributions to outage propagation. Differing from a conventional interaction graph, a dynamic interaction graph can adaptively update its parameters with changes of grid topology and hence is more accurate in online identification of the most vulnerable transmission lines and likely outage propagation paths for mitigation. Further, the paper introduces an optimal power flow model based on the dynamic interaction graph for determining the optimal control strategy to maintain transfer margins of vulnerable transmission lines and effectively mitigate outage propagation. The numerical results on the IEEE 118-bus system demonstrate the effectiveness of the proposed models and associated control strategy.