Validating GIC Modeling in the Spanish Power Grid by Differential Magnetometry

A series of experiences and recommendations are presented concerning the derivation geomagnetically induced currents (GIC) by use differential magnetometry method (DMM) under power lines. This indirect technique, intended to obtain observations validate GIC models, is an alternative measuring current flow in transformer neutrals. It a non-intrusive autonomous as procedure does not depend on grid operator. In contrast, selection suitable sites devoid human interferences, need for supply magnetometer, data acquisition transmission system, along with choice appropriate instrumentation difficulties that make just any site installation often require costly solutions. We focus methodology followed estimate flowing several lines Spanish aim validating our we share experience points. Uncertainty inherent DMM assessed, showing noise main handicap, although it can be minimized filtering. According such experience, some occasions only total DC above significant fraction 1 give magnetic signatures well level, so this figure roughly considered threshold limit detection. The low solar activity, combined mid-latitude condition Spain, limited significance available recorded data, but already report analyze results minor geomagnetic storms.