CCPA via Load Redistribution: Sequential Strategies and Vulnerability Analysis in Power Systems

Coordinated cyber-physical attacks (CCPAs) pose a critical threat to the secure operation of smart power grids. While existing studies often assume simultaneous or sequence-agnostic attack strategies, this paper proposes a sequence-aware CCPA framework that explicitly models the temporal coupling between cyber manipulation and physical sabotage. We enhance the classical load redistribution attack (LRA) by addressing four key limitations: detectability due to infeasible power flows, violation of power balance, omission of post-attack system response, and insensitivity to attack sequencing. Specifically, we formulate two distinct bilevel attack models, namely Cyber-to-Physical (C→P) and Physical-to-Cyber (P→C), and solve them via an exact KKT-based Mixed-Integer Linear Programming (MILP) reformulation and a scalable Benders decomposition (BD) framework. Experiments on IEEE 14-, 57-, and 118-bus systems demonstrate that C→P attacks induce significantly more line overloads than P→C, validating the heightened risk of cyber-initiated cascades. Moreover, our BD approach accurately identifies spatial vulnerability hotspots with high fidelity, even when the physical attack budget is extended fromRp= 1 toRp= 2, confirming the framework’s scalability and practical relevance. The results provide actionable insights for adaptive grid protection against sophisticated, sequential threats.