Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024
Abstract Geomagnetically induced current (GIC) measurements made at two 3 phase, 3 limb transformers, operating in the Halfway Bush substation in Dunedin, New Zealand have been analyzed during the May 2024 Gannon Storm. GIC measurements were combined with very low frequency radio wave AC harmonic me...
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Wiley
2025-04-01
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| Series: | Space Weather |
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| Online Access: | https://doi.org/10.1029/2024SW004235 |
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| author | M. A. Clilverd C. J. Rodger D. H. Mac Manus J. B. Brundell M. Dalzell A. Renton V. Lo A. Lapthorn A. W. Smith J. Malone‐Leigh X. Feng T. Petersen |
| author_facet | M. A. Clilverd C. J. Rodger D. H. Mac Manus J. B. Brundell M. Dalzell A. Renton V. Lo A. Lapthorn A. W. Smith J. Malone‐Leigh X. Feng T. Petersen |
| author_sort | M. A. Clilverd |
| collection | DOAJ |
| description | Abstract Geomagnetically induced current (GIC) measurements made at two 3 phase, 3 limb transformers, operating in the Halfway Bush substation in Dunedin, New Zealand have been analyzed during the May 2024 Gannon Storm. GIC measurements were combined with very low frequency radio wave AC harmonic measurements made nearby, and reactive power measurements made at key points in the substation. This study focuses on the 11 May, 00–14 UT period when geomagnetic activity was high and the 220 kV transformers, T6 and T3, experienced multiple short periods where GIC > 50 A in each transformer, maximizing at 113 A. During high GIC periods linear enhancements of even order AC harmonic intensity were identified, particularly for the 2nd and 4th harmonics, consistent with asymmetric half‐cycle transformer core saturation. Reactive power consumption (Qcon, MVAr) increased linearly when GIC levels were >30 A, consistent with the enhancement of even order AC harmonics due to transformer core saturation >30 A DC. Transformer T6 exhibited a reactive power response of 0.038 MVAr/A, while for T3 it was 0.026 MVAr/A. Simple extrapolation of these findings to extreme storm modeling of the New Zealand high voltage grid suggests that an additional ∼200–350 MVAr of generation would be required to compensate for peak increased reactive power consumption at 19 of the most affected sites during a Carrington‐level event. Such additional power requirements are likely to be within the capabilities of the power generation network. |
| format | Article |
| id | doaj-art-d6d09b613a8e430884da0b1e4101ccc6 |
| institution | Kabale University |
| issn | 1542-7390 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Wiley |
| record_format | Article |
| series | Space Weather |
| spelling | doaj-art-d6d09b613a8e430884da0b1e4101ccc62025-08-20T03:26:27ZengWileySpace Weather1542-73902025-04-01234n/an/a10.1029/2024SW004235Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024M. A. Clilverd0C. J. Rodger1D. H. Mac Manus2J. B. Brundell3M. Dalzell4A. Renton5V. Lo6A. Lapthorn7A. W. Smith8J. Malone‐Leigh9X. Feng10T. Petersen11British Antarctic Survey (UKRI‐ NERC) Cambridge UKDepartment of Physics University of Otago Dunedin New ZealandDepartment of Physics University of Otago Dunedin New ZealandDepartment of Physics University of Otago Dunedin New ZealandTranspower New Zealand Limited Wellington New ZealandTranspower New Zealand Limited Wellington New ZealandTranspower New Zealand Limited Wellington New ZealandDepartment of Electrical and Computer Engineering University of Canterbury Christchurch New ZealandDepartment of Mathematics Physics and Electrical Engineering University of Northumbria Newcastle Upon Tyne UKDepartment of Physics University of Otago Dunedin New ZealandDepartment of Physics University of Otago Dunedin New ZealandDepartment of Data Science and Geohazards Monitoring GNS Science Lower Hutt New ZealandAbstract Geomagnetically induced current (GIC) measurements made at two 3 phase, 3 limb transformers, operating in the Halfway Bush substation in Dunedin, New Zealand have been analyzed during the May 2024 Gannon Storm. GIC measurements were combined with very low frequency radio wave AC harmonic measurements made nearby, and reactive power measurements made at key points in the substation. This study focuses on the 11 May, 00–14 UT period when geomagnetic activity was high and the 220 kV transformers, T6 and T3, experienced multiple short periods where GIC > 50 A in each transformer, maximizing at 113 A. During high GIC periods linear enhancements of even order AC harmonic intensity were identified, particularly for the 2nd and 4th harmonics, consistent with asymmetric half‐cycle transformer core saturation. Reactive power consumption (Qcon, MVAr) increased linearly when GIC levels were >30 A, consistent with the enhancement of even order AC harmonics due to transformer core saturation >30 A DC. Transformer T6 exhibited a reactive power response of 0.038 MVAr/A, while for T3 it was 0.026 MVAr/A. Simple extrapolation of these findings to extreme storm modeling of the New Zealand high voltage grid suggests that an additional ∼200–350 MVAr of generation would be required to compensate for peak increased reactive power consumption at 19 of the most affected sites during a Carrington‐level event. Such additional power requirements are likely to be within the capabilities of the power generation network.https://doi.org/10.1029/2024SW004235geomagnetic induced currentsgeomagnetic stormreactive powerharmonicstransformerhigh voltage |
| spellingShingle | M. A. Clilverd C. J. Rodger D. H. Mac Manus J. B. Brundell M. Dalzell A. Renton V. Lo A. Lapthorn A. W. Smith J. Malone‐Leigh X. Feng T. Petersen Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024 Space Weather geomagnetic induced currents geomagnetic storm reactive power harmonics transformer high voltage |
| title | Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024 |
| title_full | Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024 |
| title_fullStr | Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024 |
| title_full_unstemmed | Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024 |
| title_short | Geomagnetically Induced Currents, Transformer Harmonics, and Reactive Power Impacts of the Gannon Storm in May 2024 |
| title_sort | geomagnetically induced currents transformer harmonics and reactive power impacts of the gannon storm in may 2024 |
| topic | geomagnetic induced currents geomagnetic storm reactive power harmonics transformer high voltage |
| url | https://doi.org/10.1029/2024SW004235 |
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