Visual Tool for Assessing Stability of DER Configurations on Three-Phase Radial Networks

TL;DR

This paper introduces a linearized power flow-based method and visualization tool for assessing the stability of inverter-based DER configurations in three-phase unbalanced distribution networks, enabling efficient stability evaluation without extensive simulations.

Contribution

It develops a linear state space model for Phasor-Based Control on unbalanced networks and provides a practical stability assessment method integrated into a visualization tool.

Findings

The method accurately identifies stable DER configurations.

The stability assessment requires only line impedance data.

The tool effectively evaluates multiple configurations on IEEE test feeders.

Abstract

We present a method and tool for evaluating the placement of Distributed Energy Resources (DER) on distribution circuits in order to control voltages and power flows. Our previous work described Phasor-Based Control (PBC), a novel control framework where DERs inject real and reactive power to track voltage magnitude and phase angle targets. Here, we employ linearized power flow equations and integral controllers to develop a linear state space model for PBC acting on a three-phase unbalanced network. We use this model to evaluate whether a given inverter-based DER configuration admits a stable set of controller gains, which cannot be done by analyzing controllability nor by using the Lyapunov equation. Instead, we sample over a parameter space to identify a stable set of controller gains. Our stability analysis requires only a line impedance model and does not entail simulating the system or solving an optimization problem. We incorporate this assessment into a publicly available visualization tool and demonstrate three processes for evaluating many control configurations on the IEEE 123-node test feeder (123NF).