An analytical method for nodal inertia estimation of power systems
File(s)
Author(s)
Brahma, Debargha
Singh, Abhinav Kumar
Mir, Abdul Saleem
Senroy, Nilanjan
Pal, Bikash
Type
Journal Article
Abstract
The significance of system inertia, especially its non-uniform spatial distribution, is becoming paramount in the current power system scenario. The scope of inertia estimation has traditionally been the estimation of overall or total system inertia. However, as frequency dynamics become increasingly localized with increasing penetration of inverter-based resources (IBRs), the need for higher spatial resolution (geographically localized estimate) and faster temporal resolution (online or continuous estimate) in inertia estimation becomes paramount. This paper proposes an analytical method to estimate the spatial inertia distribution down to the transmission node level, i.e., nodal inertia. Depending on data availability, the proposed method is flexible and can be used in two ways: φ to estimate nodal inertia for any given operating condition (or snapshot), or φ to continuously estimate nodal inertia for both ambient and transient conditions using available local phasor measurement unit (PMU) measurements. The novelty of the proposed method lies in its analytical formulation, which does not require rate of change of frequency (ROCOF) measurements or rate of change of power injections, making it immune to the noise associated with the estimation of these derived quantities. Additionally, the proposed method does not require defining near-zero ROCOF thresholds, which is system-specific and a non-trivial problem. The proposed method is mode-agnostic, which makes it more general than dominant mode-based linearized methods. The applicability of the proposed method is demonstrated through simulation studies performed on the IEEE 39-bus and IEEE 68-bus test systems with varying IBR penetration levels. The robustness of the method is numerically assessed against modeling and measurement uncertainties.
Date Issued
2026-01-16
Date Acceptance
2025-12-01
Citation
Journal of Modern Power Systems and Clean Energy, 2026
ISSN
2196-5625
Publisher
IEEE
Journal / Book Title
Journal of Modern Power Systems and Clean Energy
Copyright Statement
© 2026 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
10.35833/MPCE.2025.000195
Subjects
Frequency stability
inertia estimation
nodal inertia
power system dynamics
rate of change of frequency
Publication Status
Published online
Date Publish Online
2026-01-16