Geomagnetic induced currents in long subsea power cables

Abstract

This report focuses on geomagnetically induced currents (GIC) that can be induced in long subsea power cables. Literature indicates that the water depth itself, in which the cable will be laid, will not contribute to an attenuation of the geoelectric field for those water depths relevant for the Krafla power cable. However, the presence of a coast will introduce a strong enhancement. Even minor (<20 years) and moderate (~20-100 years) geomagnetic events can potentially cause considerable operational difficulty if sufficient mitigations are not in place. A close cooperation with Statnett (transmission system operator) is essential to limit any unintentional disconnection of the Krafla subsea cable.