Powerlines

Schematic showing a current (J0) in the space environment above the Earth’s surface of increasing intensity over time. This current generates a magnetic fields (B) that is also increasing in intensity over time. This magnetic field, in turn, induces geoelectric fields (E) in the Earth, generally of high (low) amplitude within rock of low conductivity (high conductivity). These geoelectric fields, in turn, drive electric currents (J1) that flow from the Earth, through ground connections at transformer substations and across high-voltage transmission lines.