Numerical simulation of currents induced by geomagnetic storms on buried pipelines: an application to the Tierra del Fuego, Argentina, gas transmission route

Varying currents, superimposed on the normal cathodic protection have been observed for many years in pipelines. These telluric currents are generally associated with variations in the Earth´s magnetic field and present a continuing problem in establishing and monitoring cathodic protection systems. This problem is enhanced when magnetic storms occur. In a previous paper, a method to calculate the induction over buried pipelines associated with an external source was developed and this effect was quantified as a function of the intensity and frequency of the external field. In the present work, the authors present the experimental tests. Simultaneous measurements of currents and natural fields are interpreted using this method, and a numerical simulation of the current induced by a magnetic storm is performed. The results show that, even for those storms considered to be of moderate intensity, the current geomagnetically induced in the buried pipeline may increase to 1000%, which suggests that this effect may represent an amount of risk high enough to justify a continuous evaluation and control