Space weather risk in power systems and pipelines

Geomagnetically induced currents (GIC) in technological systems, such as electric power transmission grids, oil and gas pipelines, telecommunication cables and railway equipment, are a harmful space weather effect at the earth's surface. In power systems GIC cause saturation of transformers, which may lead to serious problems and even to a collapse of the whole system, as occurred in Quebec in March 1989, or to permanent damage of transformers. In buried pipelines GIC give rise to corrosion problems. GIC are driven by the geoelectric field induced by a geomagnetic disturbance. The electric and magnetic fields primarily depend on ionospheric currents and secondarily on currents induced in the earth. GIC risk in a technological system can be decreased by help of forecasting methods. This requires predictions of ionospheric currents to be used as an input for the calculation of the geoelectric field and GIG. Recent developments in the calculation techniques based on the Complex Image Method (CIM) permit fast and accurate computations suitable for a time-critical application like GIC forecasting. (C) 2000 Elsevier Science Ltd. All rights reserved.