The Effects of Correctly Modeling Generator Step-Up Transformer Status in Geomagnetic Disturbance Studies
Abstract
In order to correctly model the impacts of geomagnetically induced current (GIC) flows, the generator step-up (GSU) transformer status must be properly modeled. In power flow studies, generators are typically removed from service without disconnecting their GSU transformers since the GSU transformer status has little to no impact on the power flow result. In reality, removing a generator from service involves also removing its GSU transformer from service. This difference presents a discrepancy between simulated behavior and system observations during geomagnetic disturbance (GMD) events. This paper presents GMD case studies on 2000-bus and 24,000-bus systems in which reactive power losses and geomagnetically induced currents are compared across scenarios in which the GSU transformers for the disconnected generators are either in-service or out-of-service. The results demonstrate a 3.2 to 15.5 percent error in reactive power losses when the GSU status is modeled incorrectly. Discrepancies of up to 95 A per phase for branch GIC flows and 450 A for transformer neutral GIC flows are also observed and visualized.
Keywords
Cite
@article{arxiv.2208.11232,
title = {The Effects of Correctly Modeling Generator Step-Up Transformer Status in Geomagnetic Disturbance Studies},
author = {Jessica L. Wert and Pooria Dehghanian and Jonathan Snodgrass and Thomas J. Overbye},
journal= {arXiv preprint arXiv:2208.11232},
year = {2022}
}
Comments
Presented at the 2022 North American Power Symposium (NAPS), Salt Lake City, UT, October 2022