Random wins over order!

The US electrical grid is in danger of breaking down, thanks to orderly networks!

A mathematical study of spatial networks by physicists in Israel and the U.S. says that the research builds on earlier work by incorporating a more explicit analysis of how the spatial nature of physical networks affects their fundamental stability. The upshot, published August 25 in Nature Physics, is that spatial networks are necessarily dependent on any number of critical nodes whose failure can lead to abrupt—and unpredictable—collapse. The electric grid, which operates as a series of networks that are defined by geography, is a prime example. Whenever you have such dependencies in the system, failure in one place leads to failure in another place, which cascades into collapse.

Focussing on idealized scenarios, the team found that randomly structured networks—such as social networks—degrade slowly as nodes are removed, which in the real world might mean there is time to diagnose and address a problem before a system collapses. By contrast, the connections of orderly lattice structures have more critical nodes, which increase the instability. The problem is that such orderly networks are always operating near an indefinable edge. To reduce that risk, they recommends adding a small number of longer transmission lines that provide short cuts to different parts of the grid.

The 2003 blackout stemmed from a combination of bad vegetation management—the first three lines tripped after sagging into trees but were all within their load rating—and a series of monitoring and communications breakdowns. Vegetation requirements have since been standardized, and a new generation of sensors is providing grid operators with more information about what is happening across the grid at any given moment.