A cyber-physical approach to a wide-area actionable system for the power grid

Abstract

Unexpected occurrences of large-area cascading failures due to small disturbances in worldwide electricity grids serve as evidence of their intrinsic instability. As the grid is the most fundamental critical infrastructure in any modern society, detection and mitigation of such cascading failures due to accidental failures or malicious attacks are of vital importance to both civilian and military applications. However, due to the unique physical properties of electricity, such as its travel speed, systems must be able to react within a fraction of second in order to detect and prevent occurrences of cascading failures. In this paper, by modeling the grid as a cyber-physical system, we propose a decentralized, hierarchical framework to develop and implement a wide-area actionable system, capable of detecting and mitigating potential cascading failures. The states of the grid and physical constraints are modeled as manifolds, and evolution of the grid becomes a path on the manifold. By decomposing the grid into resilience zones with minimal power flow between them, we utilize precomputed scenarios in each resilience zone to develop a parametrized model. During deployment, online phasor measurements will be used to estimate the stability within each zone and interactions among them. The detection of cascading failures will be based on the detection of cascading failing paths among the K hop trees built for each zone. We illustrate the effectiveness of the proposed approach using the 2003 Italy blackout scenarios, and we discuss practical requirements in order to deploy such a system.