GICs and gas pipeline

Australia has thousands of kilometres of pipeline that conveys natural resources to population centres. Gas pipelines are constructed of materials that allow high pressures but are susceptible to corrosion. Corrosion is a chemical process, so one of the main corrosion mitigation techniques is to record the pipe-to-soil potential (PSP) and maintain a sufficient voltage to inhibit the transfer of pipe material to the soil. This process is complicated by the PSPs induced by natural variations of the geomagnetic field and associated ionospheric currents, which have their ultimate energy source in the dynamics of space weather.

GICs have previously been studied at high latitudes where the effects of geomagnetic disturbances can be large. At high latitudes the Birkeland current system produces large deviations in the geomagnetic field, particularly during disturbed periods. GIC signals observed on low latitude pipelines (Martin, 1993; Waters et al., 2006) are likely to have different ionospheric source fields to those observed on high latitude pipelines and provide additional spectral information for comparison with model predictions.

The Space Physics group at Newcastle work with the IPS Radio and Space Services division of the Australian Bureau of Meteorology to understand the threat to the Australian electricity network from space weather. A preliminary study was published by Marshall et al., 2010.

# ref: Marshall et al., Spectral analysis of pipe-to-soil potentials with variations of the Earth's magnetic field in the Australian region, Space Weather, VOL. 8, S05002, doi:10.1029/2009SW000553, 2010

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