Grid-Forming Storage Networks: Analytical Characterization of Damping and Design Insights

TL;DR

This paper provides an analytical framework for understanding and improving the damping and stability of power systems with multiple grid-forming storage resources, focusing on inverter control parameters and storage sizing.

Contribution

It introduces a theoretical analysis of small-signal stability in grid-forming storage networks, deriving conditions for optimal droop gain design to enhance damping.

Findings

Inverter droop gains significantly influence inter-area oscillation damping.

Storage size impacts the eigenvalues related to system stability.

Proposed design conditions improve damping performance in numerical simulations.

Abstract

The paper presents a theoretical study on small-signal stability and damping in bulk power systems with multiple grid-forming inverter-based storage resources. A detailed analysis is presented, characterizing the impacts of inverter droop gains and storage size on the slower eigenvalues, particularly those concerning inter-area oscillation modes. From these parametric sensitivity studies, a set of necessary conditions are derived that the design of droop gain must satisfy to enhance damping performance. The analytical findings are structured into propositions highlighting potential design considerations for improving system stability. The findings are illustrated via numerical studies on an IEEE 68-bus grid-forming storage network.