Distributed Optimal Voltage Control with Asynchronous and Delayed Communication

TL;DR

This paper presents a distributed voltage control algorithm that allows asynchronous updates and communication delays, ensuring convergence to optimal voltage profiles in power networks with renewable energy sources.

Contribution

It introduces a novel asynchronous distributed control method that enforces power limits and guarantees convergence under delays, validated with nonlinear power flow simulations.

Findings

Algorithm converges to optimal voltage profile under linear power flow.

Effective in realistic networks with nonlinear power flow.

Robust to communication delays and asynchronous updates.

Abstract

The increased penetration of volatile renewable energy into distribution networks necessities more efficient distributed voltage control. In this paper, we design distributed feedback control algorithms where each bus can inject \emph{both active and reactive} power into the grid to regulate the voltages. The control law on each bus is only based on local voltage measurements and communication to its physical neighbors. Moreover, the buses can perform their updates \emph{asynchronously} without receiving information from their neighbors for periods of time. The algorithm enforces \emph{hard upper and lower limits} on the active and reactive powers at every iteration. We prove that the algorithm converges to the optimal feasible voltage profile, assuming linear power flows. This provable convergence is maintained under bounded communication delays and asynchronous communications. We further numerically test the performance of the algorithm using the full \emph{nonlinear AC power flow} model. Our simulations show the effectiveness of our algorithm on realistic networks with both static and fluctuating loads, even in the presence of communication delays.