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Ann. Geophys., 20, 1063-1072, 2002
www.ann-geophys.net/20/1063/2002/
© European Geosciences Union 2002
Modelling of geomagnetic induction in pipelines
L. Trichtchenko and D. H. Boteler
Geomagnetic Laboratory, Geological Survey of Canada, 7 Observatory Crescent, Ottawa, Ontario K1A 0Y3, Canada
Correspondence to: L. Trichtchenko
(ltrichtc@NRCan.gc.ca)
Abstract. Geomagnetic field
variations induce telluric currents in pipelines, which modify the
electrochemical conditions at the pipe/soil interface, possibly contributing to
corrosion of the pipeline steel. Modelling of geomagnetic induction in
pipelines can be accomplished by combining several techniques. Starting with
geomagnetic field data, the geoelectric fields in the absence of the pipeline
were calculated using the surface impedance derived from a layered-Earth
conductivity model. The influence of the pipeline on the electric fields was
then examined using an infinitely long cylinder (ILC) model. Pipe-to-soil
potentials produced by the electric field induced in the pipeline were
calculated using a distributed source transmission line (DSTL) model. The
geomagnetic induction process is frequency dependent; therefore, the
calculations are best performed in the frequency domain, using a Fourier
transform to go from the original time domain magnetic data, and an inverse
Fourier transform at the end of the process, to obtain the pipe-to-soil
potential variation in the time domain. Examples of the model calculations are
presented and compared to observations made on a long pipeline in the auroral
zone.
Key words. Geomagnetism and
paleomagnetism (geo-magnetic induction)
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