Decentralized Frequency Control using Packet-based Energy Coordination

TL;DR

This paper introduces a decentralized frequency control method for demand-side resources like electric water heaters, using a packet-based scheme to estimate and provide damping in power systems.

Contribution

It proposes a novel frequency-dependent control law for DERs that enables decentralized damping and online estimation of aggregate damping capacity.

Findings

Effective damping during frequency deviations demonstrated

Accurate online estimation of DER fleet damping capacity

Validated on a two-area power system with 400,000 DERs

Abstract

This paper presents a novel frequency-responsive control scheme for demand-side resources, such as electric water heaters. A frequency-dependent control law is designed to provide damping from distributed energy resources (DERs) in a fully decentralized fashion. This local control policy represents a frequency-dependent threshold for each DER that ensures that the aggregate response provides damping during frequency deviations. The proposed decentralized policy is based on an adaptation of a packet-based DER coordination scheme where each device send requests for energy access (also called an "energy packet") to an aggregator. The number of previously accepted active packets can then be used a-priori to form an online estimate of the aggregate damping capability of the DER fleet in a dynamic power system. A simple two-area power system is used to illustrate and validate performance of the decentralized control policy and the accuracy of the online damping estimating for a fleet of 400,000 DERs.