Simulation of Geomagnetically Induced Currents With Piecewise Layered-Earth Models

The relationship between the changes in the earth's magnetic field and the induced geoelectric field during a geomagnetic storm is a frequency-dependent transfer function that depends on earth resistivity at different depths. Taking into account geological variations over the route of transmission circuits has a significant influence on the induced geoelectric fields as well as on the distribution of geomagnetically induced current (GIC) over a geographically large network. This paper summarizes and compares the results of time-domain and steady-state GIC simulations using laterally uniform and piecewise layered-earth models.