Open AccessImproved modeling of geomagnetically induced currents in the South African power network
Author(s) -
Ngwira Chigomezyo M.,
Pulkkinen Antti,
McKinnell LeeAnne,
Cilliers Pierre J.
Publication year - 2008
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1029/2008sw000408
Subject(s) - geomagnetically induced current , earth's magnetic field , space weather , transformer , geology , geophysics , conductivity , magnetic field , meteorology , geomagnetic storm , physics , voltage , quantum mechanics
Geomagnetically induced currents (GICs), resulting from adverse space weather, have been demonstrated to cause damage to power transformers in the midlatitudes. There is growing concern over possible GIC effects in the Southern African network because of its long power lines. Previous efforts to model the electric field associated with GICs in South Africa have used a uniform ground conductivity model. In an effort to improve the modeling of GICs, GIC data together with the Hermanus Magnetic Observatory geomagnetic field data were used in order to obtain a multilayered ground conductivity structure. The method requires a definition of the network coefficients, which are then used in subsequent calculations. This study shows that GIC computed using the new network coefficients and the multilayered ground conductivity model improves the accuracy of GIC modeling. GIC statistics are then derived on the basis of the recordings of the geomagnetic field from 1996 to 2006 at Hermanus, the new network coefficients, and ground conductivity model. The geoelectric field was modeled using the plane wave method.