Coupled Cascading Failure in Energy CPS- Modeling, Prevention, and Restoration

The proposed research has two key objectives (a) develop an accurate understanding of the cascading failure mechanism and its prevention, and (b) develop a recovery plan following blackouts under uncertainty of failure locations and budget constraints. The quasi-steady-state (QSS) model of power grid used in literature for studying cascade propagation produces inaccurate results towards the later stages of blackouts, whereas a fully dynamic model is impractical for large-scale statistical analyses. To solve this, a 'temporally hybrid' and a 'spatio-temporally hybrid' model are proposed, which quantify the stress of the grid at the systems level and the component level, respectively, using trajectory sensitivity theory, and appropriately switch from the QSS to the dynamic model. Next, a unified graph-based model for interdependent power grid and communication systems is developed, which takes into account several special features of the legacy Supervisory Control and Data Acquisition (SCADA) system along with the modern Wide-Area Monitoring, Protection, and Controls (WAMPAC) system, and the observability and controllability they provide for the CPS. Furthermore, a stability-constrained remedial action scheme for cascade prevention is proposed. Finally, a new approach for progressive assessment and recovery, which leverages the hybrid power grid models and the unified communication network model, is proposed in the presence of budget constraints and failure uncertainties.