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Effect of Space Weather observed in the Czech oil pipeline network |
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Hejda, P. and Pek, J. |
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Institute of Geophysics of the CAS, Prague, Czech Republic |
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Although the buried pipelines are provided with an insulating coating, there are always points where the insulation is defective and the pipeline is threatened by corrosion. For this reason, the pipelines are equipped with a cathodic protection system which keeps the pipeline at a negative potential of about 1 to 2 volts in relation to the ground. The pipe to soil voltage in the Czech oil pipelines is checked and recorded at about 80 stations. As the pipelines represent long electric conductors they respond to electric fields induced by variations of the geomagnetic field. Variation of the pipe to soil voltage does not represent a real threat for the pipeline, as it is usually a short time effect. However the data contain interesting information about geomagnetically induced currents.
Data from autumn 2005 to 2017 were analyzed. The data were cleaned from variations caused by local sources or by artificial effects. This was done by comparison with data from neighboring stations. The variation of the pipe to soil voltages was classified by several characteristics and compared with planar model of the geoelectric field computed from geomagnetic variation observed at the Budkov Observatory. It was also possible to compare several events with data obtained by magnetotelluric field measurements. It is shown that the effect of weak magnetic disturbances is negligible as the cathodic protection can compensate it promptly. On the other hand, the signal of strong magnetic storms is quite pronounced. The statistics as well as selected events are presented. |
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