A series of 100-year extreme geoelectric field and geomagnetically induced current (GIC) scenarios are explored by taking into account the key geophysical factors associated with the geomagnetic induction process. More specifically, we derive explicit geoelectric field temporal profiles as a function of ground conductivity structures and geomagnetic latitudes. We also demonstrate how the extreme geoelectric field scenarios can be mapped into GIC. Generated statistics indicate 20 V/km and 5 V/km 100-year maximum 10-s geoelectric field amplitudes at high-latitude locations with poorly conducting and well-conducting ground structures, respectively. We show that there is an indication that geoelectric field magnitudes may experience a dramatic drop across a boundary at about 40°–60° of geomagnetic latitude. We identify this as a threshold at about 50° of geomagnetic latitude. The sub-threshold geoelectric field magnitudes are about an order of magnitude smaller than those at super-threshold geomagnetic latitudes. Further analyses are required to confirm the existence and location of the possible latitude threshold. The computed extreme GIC scenarios can be used in further engineering analyses that are needed to quantify the geomagnetic storm impact on conductor systems such as high-voltage power transmission systems. To facilitate further work on the topic, the digital data for generated geoelectric field scenarios are made publicly available.

/pdf/generation-of-100-year-geomagnetically-induced-current-z4mqtt0m87.pdf

Generation of 100-year geomagnetically induced current scenarios

Space weather describes the way in which the Sun, and conditions in space more generally, impact human activity and technology both in space and on the ground. It is now well understood that space weather represents a significant threat to infrastructure resilience, and is a source of risk that is wide-ranging in its impact and the pathways by which this impact may occur. Although space weather is growing rapidly as a field, work rigorously assessing the overall economic cost of space weather appears to be in its infancy. Here, we provide an initial literature review to gather and assess the quality of any published assessments of space weather impacts and socioeconomic studies. Generally speaking, there is a good volume of scientific peer-reviewed literature detailing the likelihood and statistics of different types of space weather phenomena. These phenomena all typically exhibit "power-law" behavior in their severity. The literature on documented impacts is not as extensive, with many case studies, but few statistical studies. The literature on the economic impacts of space weather is rather sparse and not as well developed when compared to the other sections, most probably due to the somewhat limited data that are available from end-users. The major risk is attached to power distribution systems and there is disagreement as to the severity of the technological footprint. This strongly controls the economic impact. Consequently, urgent work is required to better quantify the risk of future space weather events.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/risa.12765

The Economic Impact of Space Weather: Where Do We Stand?

Extreme space weather: impacts on engineered systems and infrastructure

[1] Geomagnetically induced currents (GICs) are a ground end manifestation of space weather processes. During large geomagnetic storms, GICs flow between the grounding points of power transformers and along electric power transmission lines connecting the transformers. In high-latitude regions, damages to power transformers are reported where storm time geomagnetic variations are very rapid and large (>1000 nT), and hence the GICs as large as or even greater than 100 A end up flowing through the windings of power transformers. At low latitudes, geomagnetic variations are less severe, and hence much smaller GIC values are generally reported there. However, the flow of GICs and their effects on power transformers are complex processes, and careful evaluation is needed even in such low-latitude regions as, for example, Brazil. We report here a study on GIC measurements in Brazil conducted under a cooperative project between FURNAS (the Brazilian electric power company) and the National Institute for Space Research. During a large geomagnetic storm, which took place on 7–10 November 2004, the GIC amplitudes, measured on the basis of geomagnetic variations in 500 kV power transmission lines in the S–E region of Brazil, were found to be around 15 A.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2006SW000282

Geomagnetically induced currents in an electric power transmission system at low latitudes in Brazil: A case study

[1] Geomagnetically Induced Currents (GIC) can be damaging to high-voltage power transmission systems. GIC are driven by rapid changes in the strength of the magnetic field external to the Earth's surface. Electric fields are produced in the ground by the interaction between this changing magnetic field, the sea and the conductivity structure of the Earth. Using a technique known as the “thin-sheet approximation,” we can determine the electric field at the Earth's surface, which in turn allows the calculation of GIC in the earthing connections of high-voltage transformers within a power grid. We describe two new developments in the modeling of GIC in the UK, though the results are applicable to GIC-related research in other regions. Firstly, we have created an updated model of the UK surface conductivity by combining a spatial database of the UK geological properties (i.e., rock type) with an estimate of the conductivity for specific formations. Secondly, we have developed and implemented a sophisticated and up-to-date model for the 400 kV and 275 kV electrical networks across the whole of Great Britain and, in addition, the 132 kV network in Scotland. We can thus deduce the expected GIC at each transformer node in the system based on the network topology from an input surface electric field. We apply these developments to study the theoretical response of the UK high-voltage power grid to modeled extreme 100 year and 200 year space weather scenarios and to a scaled version of the October 2003 geomagnetic storm, approximating a 1 in 200 year event.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/swe.20065

Prediction of extreme geomagnetically induced currents in the UK high-voltage network

A surface electric field model is used to estimate the UK surface E field during the 30 October 2003
severe geomagnetic storm. This model is coupled with a power grid model to determine the flow of
geomagnetically induced currents (GIC) through the Scottish part of the UK grid. Model data are
compared with GIC measurements at four sites in the power network. During this storm, measured and
modeled GIC levels exceeded 40 A, and the surface electric field reached 5 V/km at sites in the United
Kingdom (compared with quiet-time levels of less than 0.1 V/km). The electric field and grid models now
form part of a GIC monitoring, analysis, and warning software package with Web interface, developed for
use by the grid operator. This package also contains a daily geomagnetic activity forecast service, a solar
wind shock detector for geomagnetic storm warning, and a near-real-time geomagnetic data stream for
storm monitoring.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2005SW000156

Surface electric fields and geomagnetically induced currents in the Scottish Power grid during the 30 October 2003 geomagnetic storm

The Earth’s lithosphere and mantle respond to Space Weather through time-varying, depth-dependent induced magnetic and electric fields. Understanding the properties of these electromagnetic fields is a key consideration in modelling the hazard to technological systems from Space Weather. In this paper we review current understanding of these fields, in terms of regional and global-scale geology and geophysics. We highlight progress towards integrated European-scale models of geomagnetic and geoelectric fields, specifically for the purposes of modelling geomagnetically induced currents in power grids and pipelines.

/pdf/a-review-of-progress-in-modelling-of-induced-geoelectric-and-4l2gpdxxqw.pdf

A review of progress in modelling of induced geoelectric and geomagnetic fields with special regard to induced currents

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Advanced Imaging Techniques Provide New Near Surface Details in 3D Seismic Exploration Data and an Application to New Energy-Related Offshore Shallow Subsurface Investigations

Algorithms have been developed to automatically detect Earth bound shocks in the solar wind as measured by the ACE satellite. These involve simple threshold techniques and wavelet analysis.
One practical application of this shock detection is that it can provide power companies with advanced warning of the potential for geomagnetically induced currents. The automatically detected shocks have been tested against published lists of known shocks and accuracy statistics are presented. Another use for automated shock detection is an aid to the preparation of lists of rapid variations: SSC and SI events.
To contribute to the IAGA published list of rapid variations, as prepared by Ebro Observatory, BGS staff
routinely identify, scale and classify the events recorded at the three UK magnetic observatories. This is carried out using the criteria from the Atlas of Rapid Variations (1959) and subsequent IAGA instructions.
The usefulness of automated detection of solar wind shocks for this task is examined by testing these against lists of identified SSC and SI events.

Allan McKay

Papers

Surface electric fields and geomagnetically induced currents in the Scottish Power grid during the 30 October 2003 geomagnetic storm

A review of progress in modelling of induced geoelectric and geomagnetic fields with special regard to induced currents

Advanced Imaging Techniques Provide New Near Surface Details in 3D Seismic Exploration Data and an Application to New Energy-Related Offshore Shallow Subsurface Investigations

Automated real time detection of solar wind shocks and consequences for the identification of SSC and SI events