Open AccessA Comparison of Peak Electric Fields and GICs in the Pacific Northwest Using 1‐D and 3‐D Conductivity
Author(s) -
Gan J. L.,
Birchfield A. B.,
Shetye K. S.,
Overbye T. J.
Publication year - 2017
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1002/2017sw001677
Subject(s) - earth's magnetic field , geomagnetically induced current , electric field , conductivity , electrical resistivity and conductivity , geology , geophysics , intensity (physics) , ionosphere , geomagnetic storm , magnetic field , geodesy , physics , optics , quantum mechanics
Geomagnetically induced currents (GICs) are a result of the changing magnetic fields during a geomagnetic disturbance interacting with the deep conductivity structures of the Earth. When assessing GIC hazard, it is a common practice to use layer‐cake or one‐dimensional conductivity models to approximate deep Earth conductivity. In this paper, we calculate the electric field and estimate GICs induced in the long lines of a realistic system model of the Pacific Northwest, using the traditional 1‐D models, as well as 3‐D models represented by Earthscope's Electromagnetic transfer functions. The results show that the peak electric field during a given event has considerable variation across the analysis region in the Pacific Northwest, but the 1‐D physiographic approximations may accurately represent the average response of an area, although corrections are needed. Rotations caused by real deep Earth conductivity structures greatly affect the direction of the induced electric field. This effect may be just as, or more, important than peak intensity when estimating GICs induced in long bulk power system lines.