Gershgorin Disc-based Voltage Stability Regions for DER Siting and Control in Distribution Grids

TL;DR

This paper introduces a novel method using Gershgorin Disc Theorem to define stability regions for inverter-based renewable energy resources, improving voltage regulation and reducing violations in distribution grids.

Contribution

It develops an analytic framework for stability regions based on grid parameters, aiding renewable siting and control without reliance on communication infrastructure.

Findings

Achieves non-oscillatory voltage regulation in case study

Reduces voltage violation duration by 26%

Provides operational flexibility with economic considerations

Abstract

As a consequence of the transition to distributed and renewable energy systems, some distribution system operators are increasingly concerned about power quality, including steady-state voltage volatility. In this paper, we study the control of real and reactive power injections by inverter-based distributed energy resources to regulate voltage magnitudes and phase angles measured by sensors positioned across 3-phase unbalanced distribution grids. Our proposed controllers are agnostic to the location and type of communications supporting energy resource operations. To design the controllers, we apply the Gershgorin Disc Theorem and determine analytic stability regions in terms of renewable energy operating parameters and grid impedances. The stability regions yield direct relationships between renewable energy system siting and the convergence of voltage phasors to references. Beyond defining stability regions, we compute ranges of stable operating parameters for renewable energy systems that promote operational flexibility by including customer economics. By means of a case study on the IEEE 123-node test circuit, we observe our approach to coordinating renewable energy systems achieves non-oscillatory voltage regulation and reduces the duration of voltage violations by 26%.