Jacobian Voltage Stiffness Metric – A measure of grid-forming capability and system strength in IBR-dominated grids
File(s)
OA Location
Author(s)
Gupta, Ambuj
Chaudhuri, Balarko
O'Malley, Mark
Type
preprint
Abstract
As power systems transition toward inverterbased resource (IBR)-dominated grids, traditional system strength definitions and metrics are becoming increasingly inadequate to characterize upcoming stability challenges. Emerging definitions characterize system strength in terms of "voltage source behind impedance (VSBI)" characteristics. Similarly, Grid-ForMing (GFM) IBRs are expected to contribute voltage stiffness by exhibiting near-constant VSBI characteristics in the (sub-)transient time frame. To quantify VSBI characteristics as a measure of system strength or grid-forming capability, this paper proposes the Jacobian Voltage Stiffness Metric (JVSM), derived from the frequency-domain Jacobian. JVSM provides a measure of both small-signal voltage magnitude and phaseangle stiffness. JVSM is demonstrated to serve as a compliance criterion for evaluating the VSBI characteristics of GFM IBRs. When applied for grid strength assessment, it more effectively identifies small-signal stability problems than state-of-the-art strength metrics. The proposed JVSM is validated through electromagnetic transient simulation case studies using the National Laboratory of the Rockies (NLR, formerly NREL) and WECC-approved industry-standard GFM IBR models and on a modified IEEE 39-bus system.
Date Issued
2026-07-10
Citation
arXiv, 2026
Journal / Book Title
arXiv
Copyright Statement
Copyright © 2026 The Authors. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Subjects
System strength
grid-forming
inverter-based resources
voltage source behind impedance
Jacobian
voltage stiffness metric