Geomagnetically induced current sensitivity to multiple substation grounding resistances

Down to Earth With Nuclear Electromagnetic Pulse: Realistic Surface Impedance Affects Mapping of the E3 Geoelectric Hazard

“…To do that, we would need grid parameters: the connectivity of the grid, line resistances, and network grounding resistances [e.g., Boteler and Pirjola, 2017;North American Electric Reliability Corporation, 2013]. Unfortunately, these parameters are not generally publicly available, and, at least in the United States, grounding resistances are often either unknown [e.g., Bui et al, 2017] or difficult to obtain [e.g., Overbye et al, 2013, their Section VI]. Indeed, in an analysis of magnetic-storm induced currents on the grid of the eastern United States, Overbye et al [2012] used grounding resistivities that they describe as being "ballpark" estimates.…”