Emergence of scale-free blackout sizes in power grids

TL;DR

This paper presents a new mathematical framework linking the scale-free distribution of blackout sizes in power grids to the heavy-tailed distribution of city demands, challenging previous self-organized criticality explanations.

Contribution

It introduces a novel approach combining power flow physics with rare event analysis to explain scale-free blackout sizes in power grids.

Findings

Blackout sizes follow a scale-free distribution.

The scale-free nature is linked to city demand distributions.

Validated results on synthetic networks and the German grid.

Abstract

We model power grids as graphs with heavy-tailed sinks, which represent demand from cities, and study cascading failures on such graphs. Our analysis links the scale-free nature of blackout sizes to the scale-free nature of city sizes, contrasting previous studies suggesting that this nature is governed by self-organized criticality. Our results are based on a new mathematical framework combining the physics of power flow with rare event analysis for heavy-tailed distributions, and are validated using various synthetic networks and the German transmission grid.