Surface electric fields and geomagnetically induced currents in the Scottish Power grid during the 30 October 2003 geomagnetic storm

A surface electric field model is used to estimate the UK surface E field during the 30 October 2003 severe geomagnetic storm. This model is coupled with a power grid model to determine the flow of geomagnetically induced currents (GIC) through the Scottish part of the UK grid. Model data are compared with GIC measurements at four sites in the power network. During this storm, measured and modeled GIC levels exceeded 40 A, and the surface electric field reached 5 V/km at sites in the United Kingdom (compared with quiet-time levels of less than 0.1 V/km). The electric field and grid models now form part of a GIC monitoring, analysis, and warning software package with Web interface, developed for use by the grid operator. This package also contains a daily geomagnetic activity forecast service, a solar wind shock detector for geomagnetic storm warning, and a near-real-time geomagnetic data stream for storm monitoring.