Characteristics of Geomagnetically Induced Currents in the B. C. Hydro 500 kV System

The spectral and spatial characteristics of the geomagnetic field variations and electric field variations are considered in relation to their effect on the resulting geomagnetically induced currents (GIC's) that flow in power systems. Field data on GIC's obtained on the B. C. Hydro 500 kV system are shown to be consistent with the characteristics of the inducing fields. It is shown that because of the spatial characteristics of the electric field, actual GIC's may be higher than would be predicted using the assumption of a uniform electric field throughout the power system.