Date of Award
5-2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Electrical Engineering
Committee Chair/Advisor
Sukumar Brahma
Committee Member
Ramtin Hadidi
Committee Member
Chris S. Edrington
Abstract
Although a power system is nonlinear during healthy operation because of constant power loads and controlled power injections from the sources, a conventional power system fed by synchronous generators is linear during fault, and can be represented by bus impedance matrix (Z-bus), which is useful in power system analyses such as short circuit (SC) analysis. However, With increasing penetration of inverter-based resources (IBRs) in the system, the assumption of linearity of the faulted network does not hold. This impacts the analyses relying on Z-bus and Thevenin’s equivalent impedance (TEI), such as certain protection schemes set using short circuit analysis. Therefore, it’s crucial to perform research on finding alternative methods to the established practices that use the linearity assumption of the power system.
The work done in this thesis, first, analyzes how the Z-bus and TEI of the power
system network are affected by increasing penetration of IBRs. IEEE nine bus transmission network simulated in PSCAD/EMTDC is used as a test case for this study. Through the results of this study, it is demonstrated that the concept of Z-bus gets broken down in the presence of IBRs. This implies that the conventional phasor-domain linear fault model becomes invalid due to the highly nonlinear, current-limited, and proprietary behavior of controllers dictating the response of renewable sources to faults in the power grid.
The second work significantly advances the state of research in this field by proposing a framework that can correctly perform short circuit analysis in bulk power grids for any penetration of IBRs. The method is tested for accuracy, convergence, and scalability by comparing its results with results from time-domain simulations of faults on two IEEE transmission systems.
Recommended Citation
Kunwar, Dol, "Phasor-Domain Short-Circuit Analysis of Power Transmission Systems in the Presence of Inverter-Based Resources" (2024). All Theses. 4316.
https://tigerprints.clemson.edu/all_theses/4316
Author ORCID Identifier
https://orcid.org/0009-0007-1660-6268