GEOSCAN Search Results: Fastlink


TitleFrequency considerations in GIC applications
AuthorTrichtchenko, LORCID logo
SourceSpace Weather vol. 19, issue 8, 2021 p. 1-26, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20210242
Mediapaper; digital; on-line
File formatpdf
Subjectsgeophysics; Science and Technology; spectral analyses; geomagnetism; geomagnetic variations; magnetic storms; sampling techniques; sampling methods; Space sciences
Illustrationsflow charts; frequency distribution diagrams; plots; tables
ProgramPublic Safety Geoscience Assessing space weather hazards
Released2021 08 08
AbstractGeomagnetically 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.

Date modified: