| Title | Frequency considerations in GIC applications |
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| Author | Trichtchenko, L |
| Source | Space Weather vol. 19, issue 8, 2021 p. 1-26, https://doi.org/10.1029/2020SW002694  Open Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210242 |
| Publisher | Wiley |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf |
| Subjects | geophysics; Science and Technology; spectral analyses; geomagnetism; geomagnetic variations; magnetic storms; sampling techniques; sampling methods; Space sciences |
| Illustrations | flow charts; frequency distribution diagrams; plots; tables |
| Program | Public Safety Geoscience Assessing space weather hazards |
| Released | 2021 08 08 |
| Abstract | Geomagnetically induced currents (GIC) are a phenomenon well known for its negative effects on the operations of power systems. To efficiently mitigate them requires different types of power system
modeling, from GIC to alternating current harmonic generation, to three-dimensional finite element models of transformers. GIC are initiated by variations of the geomagnetic field in the presence of the conductive Earth, that is, the geophysical
variables characterized by continuous frequency spectra, making GIC also exhibit continuous spectra. In order to adequately estimate their variations and peak values for mitigation purposes, an analysis is required of how sampling rate and spectral
frequency content impact the measured characteristics of GIC and harmonics. The study is based on the geomagnetic measurements and the power network data (i.e., GIC and harmonics) with high sampling rates recorded during two geomagnetic storms, March
31, 2001 and July 26-27, 2004. Availability of data covering both the source and the result of geomagnetic storm impacts on power grid allows (a) analysis of the influence of spectral content on adequate representation of both geomagnetic and
geoelectric variations during the intervals with significant increases in GIC and harmonics and (b) identifying the sampling rate sufficient to usefully represent the network response presented as GIC and harmonics variations. In summary, the
adequate sampling rate is suggested and the deficiencies associated with undersampling of the geoelectric and GIC variations are identified and discussed. |
| Summary | (Plain Language Summary, not published)
Geomagnetic disturbances can have a serious effect on power systems. Currents induced in power lines flow to ground through substation transformers. Here
they cause saturation of the transformer core, which can lead to a variety of problems. Increased heating has caused transformers to burn out. In addition, extra harmonics generated in the transformer produce unwanted relay operations, suddenly
tripping out power lines. To help engineers properly model the effect, this paper provides the comparative analysis of different geomagnetic data in their capabilities of adequate representation of geomagnetically induced currents and harmonics. In
conclusion, it gives the recommendations on the use of the sufficiently detailed description of geomagnetic field variations. |
| GEOSCAN ID | 328861 |
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