Hybrid cascading outage analysis of extreme events with optimized corrective actions

Power systems are vulnerable to extreme contingencies (like an outage of a major generating substation) that can cause significant generation and load loss and can lead to further cascading outages of other transmission facilities and generators in the system. Some cascading outages are seen within minutes following a major contingency, which may not be captured using only the dynamic simulation of the power system that are usually run for 30 or 40 seconds. The utilities plan for contingencies based on either dynamic or steady-state analysis separately, which may not accurately capture the effect of one process on the other. We addressed this gap in cascading outage analysis by developing the Dynamic Contingency Analysis Tool (DCAT), which can analyze the hybrid dynamic and steady-state behavior of power systems including protection system models in dynamic simulations, and by simulating corrective actions in post-transient steady-state conditions. One of the important implemented steady-state processes is to mimic operator corrective actions to mitigate aggravated states caused by dynamic cascading. This paper formulates an optimization model, called Optimal Power Flow with Corrective Actions (OPFCA), for selecting corrective actions that utility operators can take during major contingencies and thus automate hybrid dynamic/steady-state cascading outage mitigation. The improved DCAT framework with OPFCA is demonstrated on the 3120-bus Polish system.