Asymmetry underlies stability in power grids

TL;DR

This paper reveals that introducing heterogeneity among generators in power grids can enhance stability, demonstrating a novel phenomenon called converse symmetry breaking where asymmetry supports symmetric stable states.

Contribution

The study provides the first real-world demonstration of converse symmetry breaking and introduces a general method to identify this effect in network systems.

Findings

Heterogeneity can improve power grid stability.

Converse symmetry breaking explains how asymmetry maintains symmetric states.

Method applicable to other networks relying on behavioral homogeneity.

Abstract

Behavioral homogeneity is often critical for the functioning of network systems of interacting entities. In power grids, whose stable operation requires generator frequencies to be synchronized--and thus homogeneous--across the network, previous work suggests that the stability of synchronous states can be improved by making the generators homogeneous. Here, we show that a substantial additional improvement is possible by instead making the generators suitably heterogeneous. We develop a general method for attributing this counterintuitive effect to converse symmetry breaking, a recently established phenomenon in which the system must be asymmetric to maintain a stable symmetric state. These findings constitute the first demonstration of converse symmetry breaking in real-world systems, and our method promises to enable identification of this phenomenon in other networks whose functions rely on behavioral homogeneity.