Curing Braess' Paradox by Secondary Control in Power Grids

TL;DR

This paper demonstrates that strong secondary control in power grids can stabilize the system and counteract Braess' paradox, which occurs when adding capacity worsens performance, emphasizing demand control's role in grid stability.

Contribution

The study shows that secondary control can cure Braess' paradox in power grids, providing a new functional benefit and insights into demand control and grid topology.

Findings

Strong secondary control ensures dynamical stability.

Secondary control can eliminate Braess' paradox effects.

Demand control is crucial for stable grid operation.

Abstract

Robust operation of power transmission grids is essential for most of today's technical infrastructure and our daily life. Adding renewable generation to power grids requires grid extensions and sophisticated control actions on different time scales to cope with short-term fluctuations and long-term power imbalance. Braess' paradox constitutes a counterintuitive collective phenomenon that occurs if adding new transmission line capacity to a network increases loads on other lines, effectively reducing the system's performance and potentially even entirely removing its operating state. Combining simple analytical considerations with numerical investigations on a small sample network, we here study dynamical consequences of secondary control in AC power grid models. We demonstrate that sufficiently strong control not only implies dynamical stability of the system but may also cure Braess' paradox. Our results highlight the importance of demand control in conjunction with grid topology for stable operation and reveal a new functional benefit of secondary control.