Even-Order Harmonic Distortion Observations During Multiple Geomagnetic Disturbances: Investigation From New Zealand
Crack, M.; Rodger, C.J.; Clilverd, M. ORCID: https://orcid.org/0000-0002-7388-1529; Mac Manus, D.H.; Martin, I.; Dalzell, M.; Subritzky, S.P.; Watson, N.R.; Petersen, T.. 2024 Even-Order Harmonic Distortion Observations During Multiple Geomagnetic Disturbances: Investigation From New Zealand. Space Weather, 22 (5), e2024SW003879. 19, pp. 10.1029/2024SW003879
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© 2024. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Space Weather - 2024 - Crack - Even‐Order Harmonic Distortion Observations During Multiple Geomagnetic Disturbances .pdf - Published Version Available under License Creative Commons Attribution Non-commercial No Derivatives 4.0. Download (2MB) | Preview |
Abstract/Summary
Large geomagnetic storms are a space weather hazard to power transmission networks due to the effects of Geomagnetically Induced Currents (GICs). GIC can negatively impact power transmission systems through the generation of even-order current and voltage harmonics due to half-cycle transformer saturation. This study investigates a decade of even-order voltage total harmonic distortion (hereon referred to as Even-Order Total Harmonic Distortion (ETHD)) observations provided by Transpower New Zealand Ltd., the national system operator. We make use of ETHD measurements at 139 locations throughout New Zealand, monitored at 377 separate circuit breakers, focusing on 10 large geomagnetic disturbances during the period 2013–2023. Analysis identified 5 key substations, which appeared to act as sources of ETHD. The majority of these substations include single phase transformer banks, and evidence of significant GIC magnitudes. The ETHD from the source substations was found to propagate into the surrounding network, with the percentage distortion typically decaying away over distances of 150–200 km locally, that is, at a rate of −0.0043 %km−1. During the study period some significant changes occurred in the power network, that is, removal of the Halfway Bush (HWB) single phase bank transformer T4 in November 2017, and decommissioning of the New Plymouth substation in December 2019. Decommissioning of these two assets resulted in less ETHD occurring in the surrounding regions during subsequent geomagnetic storms. However, ETHD still increased at HWB with increasing levels of GIC, indicating that three phase transformer units were still susceptible to saturation, albeit with about 1/3 of the ETHD percentage exhibited by single phase transformers.
Item Type: | Publication - Article |
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Digital Object Identifier (DOI): | 10.1029/2024SW003879 |
ISSN: | 1542-7390 |
Date made live: | 26 Apr 2024 10:16 +0 (UTC) |
URI: | https://nora.nerc.ac.uk/id/eprint/537346 |
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