The U.S. electrical grid faces an unprecedented convergence of threats—including cyber intrusions, physical attacks, aging infrastructure, and climate-driven extreme weather events—that interact in complex, nonlinear ways to amplify cascading failure risk. Despite growing recognition of these compound hazards, existing risk assessment frameworks predominantly evaluate threat vectors in isolation, failing to capture the synergistic dynamics that produce catastrophic, system-wide blackouts. This dissertation addresses this critical gap by developing and validating the Multi-Vector Grid Risk Assessment Framework (MV-GRAF), an integrated computational model that synthesizes network topology analysis, multi-vector threat simulation, agent-based modeling, and Bayesian inference to quantify cascading failure probability under compound threat scenarios. The study employed 100,000 Monte Carlo simulations on a validated model of the U.S. high-voltage transmission network comprising 4,218 nodes and 5,697 edges. Results revealed that simultaneous cyber-physical threats produce superlinear risk amplification, with a Risk Amplification Factor (RAF) of 3.70—meaning compound threat probability exceeds the product of individual threat probabilities by nearly fourfold. Nodes exhibiting the confluence of high betweenness centrality, above-median age, and below-median cybersecurity investment were 2.83 times overrepresented in critical failure pathways. MV-GRAF achieved superior predictive performance (AUC-PR = 0.812) compared to single-threat models (AUC-PR ≈ 0.72), and identified a critical demand-to-capacity threshold (ρ* = 0.85) marking the transition from resilient to fragile grid behavior. Cascade size distributions followed a power-law with exponent α ≈ 1.8, consistent with self-organized criticality theory. The framework was validated against three historical events: the 2003 Northeast Blackout, 2021 Texas Winter Storm Uri, and 2022 Moore County substation attacks. These findings provide actionable guidance for grid operators, regulators, and national security agencies seeking to prioritize infrastructure hardening investments and develop integrated resilience strategies.
Laszlo Pokorny (Sat,) studied this question.