GEOSCAN Search Results: Fastlink


TitleGeoelectric fields due to small-scale and large-scale source currents
AuthorZheng, K; Pirjola, R J; Boteler, D H; Liu, L -G
SourceIEEE Transactions on Power Delivery (Institute of Electrical and Electronics Engineers) vol. 28, no. 1, 2013 p. 442-449,
Alt SeriesEarth Sciences Sector, Contribution Series 20140021
Mediapaper; on-line; digital
File formatpdf
Subjectsgeophysics; geoelectric variations; geomagnetism; geomagnetic fields; geomagnetic variations; electric power
Illustrationsplots; graphs
ProgramNorthern Canada Geohazards Project, Public Safety Geoscience
AbstractGeomagnetically induced currents (GIC) produced by the geoelectric fields at the earth's surface may affect the normal operation of power systems. These electric fields are produced by magnetospheric-ionospheric currents and are affected by currents induced within the ground. To investigate the effects of the geoelectric field due to different source currents, we examine the ratio of the geoelectric field to t the geomagnetic field (surface impedance) as a function of the horizontal distance from the source, and of the height and frequency of the source. The small-scale and large-scale surface impedance (ZS and ZL) are given by the 'line current' and 'plane wave' sources, respectively. We show that ZS may sometimes be significantly different from ZL, so the use of the latter in connection with studies of GIC will lead to erroneous results. However, when the distance from the source increases or the frequency considered increases, ZS approaches ZL.
Summary(Plain Language Summary, not published)
Space weather refers to the dynamic conditions on the Sun and in the space environment, in particular, in the near-Earth environment, that can affect critical infrastructure. NRCan operates the Canadian Space Weather Forecast Centre and conducts research into space weather effects on power systems, pipelines, satellites, radio communications and GNSS positioning to help Canadian industry understand and mitigate the effects of space weather. This paper examines how the spatial extent of the source fields affects the size of the geo-electric fields that can be a hazard to power systems.