In situ estimation of IBR models for analyzing sub-synchronous ocscillations
File(s)
Accepted version
Author(s)
Gao, Jianli
Javaid, Muhammad Sharjeel
Bhattacharjee, Debraj
Chen, Youhong
Chaudhuri, Balarko
Type
Journal Article
Abstract
The opaqueness of vendor-specific black-box models
of inverter-based resources (IBRs) is a barrier to the systematic analysis of IBR-induced sub-synchronous oscillations (SSO). Existing approaches via impedance scan require isolating each IBR from the power system and interfacing it with a voltage or current source. However, this procedure is not feasible when the IBR device is embedded within the rest of the system (RoS). In this paper, we propose an augmented eigensystem realization
algorithm (ERA)-based method to estimate the IBR model in situ, i.e., while the IBR remains connected to RoS. The core idea is to disentangle the IBR’s impedance spectra from its closed-loop voltage and current responses to a pulse probing. Notably, the augmented ERA enables automated model order selection, ensuring scalability for realistic IBR-rich zones of a power grid. The estimated linearized IBR models are then combined with the known RoS model, which yields a linearized state-space model of the overall power system. For validation, the case studies demonstrate the applicability and scalability of the proposed method. The frequency-domain and time-domain responses of the estimated IBR models closely match those of the actual models. Modal analysis accurately identifies the IBR with dominant contribution to poorly damped SSO, therefore enabling targeted and effective mitigation.
of inverter-based resources (IBRs) is a barrier to the systematic analysis of IBR-induced sub-synchronous oscillations (SSO). Existing approaches via impedance scan require isolating each IBR from the power system and interfacing it with a voltage or current source. However, this procedure is not feasible when the IBR device is embedded within the rest of the system (RoS). In this paper, we propose an augmented eigensystem realization
algorithm (ERA)-based method to estimate the IBR model in situ, i.e., while the IBR remains connected to RoS. The core idea is to disentangle the IBR’s impedance spectra from its closed-loop voltage and current responses to a pulse probing. Notably, the augmented ERA enables automated model order selection, ensuring scalability for realistic IBR-rich zones of a power grid. The estimated linearized IBR models are then combined with the known RoS model, which yields a linearized state-space model of the overall power system. For validation, the case studies demonstrate the applicability and scalability of the proposed method. The frequency-domain and time-domain responses of the estimated IBR models closely match those of the actual models. Modal analysis accurately identifies the IBR with dominant contribution to poorly damped SSO, therefore enabling targeted and effective mitigation.
Date Issued
2026-09-01
Date Acceptance
2026-04-11
Citation
IEEE Transactions on Power Systems, 2026, 41 (5), pp.3935-3947
ISSN
0885-8950
Publisher
Institute of Electrical and Electronics Engineers
Start Page
3935
End Page
3947
Journal / Book Title
IEEE Transactions on Power Systems
Volume
41
Issue
5
Copyright Statement
Copyright This paper is embargoed until publication. Once published the author’s accepted manuscript will be made available under a CC-BY License in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy).
Publication Status
Published
Date Publish Online
2026-04-14