USGS Science⌕ Search
Home/Archive/USGS

USGS · 70195684

Calculation of voltages in electric power transmission lines during historic geomagnetic storms: An investigation using realistic earth impedances

Greg M. Lucas·Jeffrey J. Love·Anna Kelbert
View original source ↗Export metadata ↓

Abstract

Commonly, one-dimensional (1-D) Earth impedances have been used to calculate the voltages induced across electric power transmission lines during geomagnetic storms under the assumption that much of the three-dimensional structure of the Earth gets smoothed when integrating along power transmission lines. We calculate the voltage across power transmission lines in the mid-Atlantic region with both regional 1-D impedances and 64 empirical 3-D impedances obtained from a magnetotelluric survey. The use of 3-D impedances produces substantially more spatial variance in the calculated voltages, with the voltages being more than an order of magnitude different, both higher and lower, than the voltages calculated utilizing regional 1-D impedances. During the March 1989 geomagnetic storm 62 transmission lines exceed 100 V when utilizing empirical 3-D impedances, whereas 16 transmission lines exceed 100 V when utilizing regional 1-D impedances. This demonstrates the importance of using realistic impedances to understand and quantify the impact that a geomagnetic storm has on power grids.

Explore related subjects

Space WeatherArticle
90° N90° S · 180° W ← longitude → 180° E
Source-reported bounding extent: 35.23664622093195° to 41.30257109430557° latitude; -80° to -74.1357421875° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Greg M. Lucas, Jeffrey J. Love, Anna Kelbert. 2018-02-26. Calculation of voltages in electric power transmission lines during historic geomagnetic storms: An investigation using realistic earth impedances. https://doi.org/10.1002/2017sw001779

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2025

The impact of the May 1921 superstorm on American telecommunication systems

A compilation is presented of impacts (interference and damage) realized on long-line telegraph and telephone systems across North America during the 13-16 May 1921 magnetic storm. Impacts occurred primarily during local nighttime, after the third of four sudden commencements, and during the storm’s most-prominent main phase. Impacts are attributed to rapid and high-amplitude geomagnetic field variation generated by substorms. This induced potential di erences and between the grounding points of communication networks that were su cient to cause system interference and damage. In the United States, impacts were concentrated in the Midwest and in the East, regions characterized by high electromagnetic surface impedance. Given technological changes, modern telecommunication systems are less exposed to storms like that of May 1921, while power-grid systems are now more exposed to them.

Space Weather↗
USGS2025

What is the lowest latitude of discrete aurorae during superstorms?

From a survey of published accounts of visual sightings of aurorae, a compilation is presented of the lowest identified geomagnetic latitude at which discrete aurorae were seen at local zenith during magnetic storms having intensities with maximum − Dst > 200 nT. The compilation includes data for the superstorms of 2 September 1859, 4 February 1872, and 15 May 1921. A statistical model is developed representing the equatorward boundary of discrete aurorae versus storm intensity. The model indicates that a once-per-century storm would likely induce discrete aurorae at zenith down to a geomagnetic latitude of 34 ° . Insofar as aurorae can be taken as a proxy for electrojet currents, such a storm would expose many nighttime electric-power systems, in the contiguous United States or Europe, to high levels of geomagnetic disturbance. A Carrington-class storm would induce discrete aurorae down to 24 ° . These exposures are much greater than those indicated in recent numerical simulations of extreme magnetic storms. Using the model to infer storm intensity from reports of low-latitude aurorae, a storm on 28 August 1859, likely had maximum − Dst = 673 nT. That this storm occurred just a few days before the Carrington storm of 2 September (maximum − Dst = 964 nT) deserves attention. A storm that occurred on 17 September 1770 is estimated to have had maximum − Dst = 928 nT. The vision of Ezekiel could have been inspired by aurorae from a storm with maximum − Dst = 550 nT.

Space Weather↗
USGS2025

Multi-scale intense geoelectric and geomagnetic field perturbations observed after an interplanetary magnetic field turning

Intense geoelectric fields during geomagnetic storms generate geomagnetically induced currents in power grids and other infrastructure, necessitating an understanding of their causes, for example, through coordinated space and ground observations. This study investigates localized intense geoelectric ( E ) and geomagnetic ( B ) field perturbations following an Interplanetary Magnetic Field (IMF) turning during a geomagnetic storm on 25 October 2011. Observations from EarthScope magnetotelluric sites in the upper Midwest United States revealed shorter period ( ∼ 1 min) ultra-low-frequency (ULF) waves superimposed on longer period ( ∼ 10 min) perturbations in both E and B fields. These sites, located at ∼ 19 hr magnetic local time and 56 −57 ° magnetic latitude, recorded large amplitude E and B perturbations. Ground-based all-sky imagers showed auroral brightening with sunward and poleward propagation, while upstream spacecraft linked the perturbations to an IMF turning and solar wind dynamic pressure impulse. The longer-period E and B field perturbations likely stem from localized ionospheric currents tied to substorm auroral activity post-IMF turning. The combination of ionospheric currents, ULF waves, and the Earth's varying conductivity produces intense geoelectric fields of ≥ 2 V/km in the upper Midwest. A comparison using input data and software compatible with the NOAA/USGS geoelectric field nowcast model revealed its limitations in capturing such events due to the temporal and spatial resolution of the underlying data. Using 1-s geomagnetic field data can improve geoelectric field models by capturing short-period and large spatial scale waves, although localized magnetic perturbations remain underestimated due to insufficient ground magnetometer density.

Space Weather↗