Geomagnetic effects modelling for the PJM interconnection system. I. Earth surface potentials computation

The authors describe an ionospheric source current model and the development of an Earth resistivity model used to calculate geomagnetic induced currents (GIC) on the Pennsylvania-New Jersey-Maryland interconnection (PJM). The ionospheric current was modeled as a Gaussian distributed current sheet above the Earth. Geological details are included by dividing the PJM service area into 11 different Earth resistivity regions. The resulting Earth surface potential (ESP) at each power system substation was then calculated