Understanding of geomagnetic storm environment for high voltage power grids

This Technical Brochure has collected and evaluated digitally measured magnetic field environments throughout the world, with emphasis on the larger geomagnetic storms that have occurred since 1989. This data collection effort emphasized 3 basic types of geomagnetic storm waveforms of direct interest to the electric power industry: Sudden Impulse (SI) waveforms, Electrojet waveforms, and Coronal Hole High Speed Stream (CHHSS) waveforms. Each of these types of waveforms induces different geomagnetically induced currents (GICs) that have different magnitudes, time durations and variations with latitude on the Earth.