Congestion and Cascades in Electric Power Networks

Congestion and Cascades in Electric Power Networks

Network topology greatly influences system robustness

Image of Power_grids_small.jpg
Example stylized network topologies (at left; fishnet above scale free below) and time series for cascade size (above) and cascade size distributions (below).

Cascading failure can have devastating results within and among infrastructures. We developed Polynet, an agent-based model that simulates cascading failure for application to the electric power grid. That analysis led to the development of Loki Power, an abstract representation of the Western Electric Coordinating Council (WECC) high-voltage electric power transmission network.

For the stylized electric power grid, our initial simulations demonstrate that the addition of geographically unrestricted random transactions can eventually push a grid to cascading failure, thus supporting the hypothesis that actions of unrestrained power markets (without proper security coordination on market actions) can undermine large scale system stability.

We also find that network topology greatly influences system robustness. Homogeneous networks that are "fish-net" like can withstand many more transaction perturbations before cascading than can scale-free networks. Interestingly, when the homogeneous network finally cascades, it tends to fail in its entirety, while the scale-free tends to compartmentalize failure and thus leads to smaller, more restricted outages.

Journal Articles


  • Advanced Simulation for Analysis of Critical Infrastructure: Abstract Cascades, the Electric power grid, and Fedwire, Sandia National Laboratories Report, 2004 [PDF]
  • Towards Risk-Based Management of Critical Infrastructures: Enabling Insights and Analysis Methodologies from a Focused Study of the Bulk Power Grid,┬áSandia National Laboratories report, 2008 [PDF]