Understanding Braess' Paradox in power grids

TL;DR

This paper experimentally demonstrates Braess' paradox in an AC power grid, revealing how adding capacity can counterintuitively reduce system performance, and offers a topological theory for predicting such effects to guide grid planning.

Contribution

It provides the first experimental validation of Braess' paradox in realistic power grids and develops a topological theory to predict paradoxical grid extensions.

Findings

Braess' paradox occurs in AC power grids.

Adding lines can decrease system robustness.

A topological model predicts Braessian extensions.

Abstract

The ongoing energy transition requires power grid extensions to connect renewable generators to consumers and to transfer power among distant areas. The process of grid extension requires a large investment of resources and is supposed to make grid operation more robust. Yet, counter-intuitively, increasing the capacity of existing lines or adding new lines may also reduce the overall system performance and even promote blackouts due to Braess' paradox. Braess' paradox was theoretically modeled but not yet proven in realistically scaled power grids. Here, we present an experimental setup demonstrating Braess' paradox in an AC power grid and show how it constrains ongoing large-scale grid extension projects. We present a topological theory that reveals the key mechanism and predicts Braessian grid extensions from the network structure. These results offer a theoretical method to understand and practical guidelines in support of preventing unsuitable infrastructures and the systemic planning of grid extensions.