Nonlocal failures in complex supply networks by single link additions

TL;DR

This paper investigates how adding single links to complex supply networks can unexpectedly cause nonlocal failures and destabilize the system, highlighting the need for careful network upgrades.

Contribution

It reveals that local topological changes can have counter-intuitive nonlocal effects, including destabilization and failures, across various supply network types.

Findings

Adding links can both promote and degrade network stability.

Nonlocal overloads and failures can emerge remotely from added links.

The phenomenon is related to Braess' paradox and occurs across different supply networks.

Abstract

How do local topological changes affect the global operation and stability of complex supply networks? Studying supply networks on various levels of abstraction, we demonstrate that and how adding new links may not only promote but also degrade stable operation of a network. Intriguingly, the resulting overloads may emerge remotely from where such a link is added, thus resulting in nonlocal failure. We link this counter-intuitive phenomenon to Braess' paradox originally discovered in traffic networks. We use elementary network topologies to explain its underlying mechanism for different types of supply networks and find that it generically occurs across these systems. As an important consequence, upgrading supply networks such as communication networks, biological supply networks or power grids requires particular care because even adding only single connections may destabilize normal network operation and induce disturbances remotely from the location of structural change and even global cascades of failures.