EMRP2.13 | Measuring, modelling and forecasting Geomagnetically Induced Currents in grounded infrastructure
Measuring, modelling and forecasting Geomagnetically Induced Currents in grounded infrastructure
Co-organized by ST4
Convener: Ciaran Beggan | Co-conveners: Adamantia Zoe Boutsi, Andrew Dimmock, Rachel L. BaileyECSECS, Stavros Dimitrakoudis
Posters on site
| Attendance Wed, 26 Apr, 14:00–15:45 (CEST)
Hall X2
Posters virtual
| Attendance Wed, 26 Apr, 14:00–15:45 (CEST)
Wed, 14:00
Wed, 14:00
Geomagnetically Induced Currents (GICs) can damage grounded infrastructure such as high voltage transformers, oil and gas pipelines and rail networks. Understanding their impact is vital for protecting critical national infrastructure from harm and reducing any economic consequences. GICs are caused by geoelectric fields induced in the resistive subsurface of the Earth during periods of rapid change of the magnetic field, typically in geomagnetic storms; however, an increasing body of evidence shows they occur in nominally quiet times too. We seek contributions from studies that measure (directly or indirectly) or model GICs in grounded infrastructure to assess the potential hazard and vulnerability of the infrastructure and to produce reliable models with which to forecast the potential effects of severe space weather events.

Posters on site: Wed, 26 Apr, 14:00–15:45 | Hall X2

Chairperson: Rachel L. Bailey
Rute Santos, Maria Alexandra Pais, Fernando Pinheiro, João Cardoso, and Joana Alves Ribeiro

Geomagnetically Induced Currents (GICs) are one of the main hazards of Space Weather for modern society since they may lead to electricity blackouts over large regions. The awareness and comprehension of GICs on power systems are the keys to dipping into a more resilient and robust energy system.

This study aims to understand the real contribution of shield wires (ShW) in GIC simulations. ShW are protective cables against atmospheric discharges for transmission lines and are commonly connected to the ground at substations and, often, at each supporting pylon. Although ShW represent an additional path for GICs, they are in general not considered in simulations. Possible reasons might be the need for more information on ShW parameters from the transmission system operators, as well as the increase in computational time. But another reason has possibly been the conclusions drawn in preliminary studies, showing that the ShW effect on GICs should be small.

By applying the equivalent circuit derived in [1], GIC simulations were obtained for the entire Portuguese power grid using realistic parameters for the grid and a 3D conductivity model. Simulations were carried out using an adaptation of GEOMAGICA [2] by calculating a realistic induced electric field and determining GIC magnitudes in each transformer. Also, more tests were done using the analogue circuit simulator software LTSpice to calculate GIC in the power grid using the induced electric field calculated through GEOMAGICA.

Results for different geomagnetic storms are presented and compared with GIC measurements at the transformer neutral in a particular substation of the Portuguese power network.


[1] Santos, R., Pais, M. A., Ribeiro, J. A., Cardoso, J., Perro, L., & Santos, A. (2022). Effect of shield wires on GICs: Equivalent resistance and induced voltage sources. International Journal of Electrical Power & Energy Systems, 143, 108487.

[2] Bailey, R. L., Halbedl, T. S., Schattauer, I., Römer, A., Achleitner, G., Beggan, C. D., ... & Leonhardt, R. (2017, June). Modelling geomagnetically induced currents in midlatitude Central Europe using a thin-sheet approach. In Annales Geophysicae (Vol. 35, No. 3, pp. 751-761). Copernicus GmbH.

How to cite: Santos, R., Pais, M. A., Pinheiro, F., Cardoso, J., and Alves Ribeiro, J.: Realistic estimates of the shield wire effect on the Portuguese power grid, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-840, https://doi.org/10.5194/egusphere-egu23-840, 2023.

The assessment of GICs based on time-domain transfer functions
Mikhail Kruglyakov, Craig Rodger, Daniel Mac Manus, Michael Dalzell, and Tanja Petersen
Rachel Bailey, Philipp Schachinger, Dennis Albert, Georg Achleitner, and Roman Leonhardt

Geomagnetically induced currents (GICs) are a consequence of space weather activity that can affect power grid operation and stability worldwide. GICs manifest as quasi-direct currents flowing between the power grids and the conductive earth, and are often measured with a Hall sensor placed at the transformer neutral. Globally, the number of power grid substations with GIC measurements has grown quickly in recent years, but Austria remains one of the few countries with a dataset of long-term GIC observations. GIC measurements in substations in the Austrian power grid have been carried out since 2016, with a maximum of seven concurrent substation measurements, providing a unique opportunity for GIC measurement analysis.

In this study, we present an analysis of the last six years of GIC measurements in Austria. Seven custom-built stand-alone GIC measurement systems have been installed in the 220 and 380 kV transmission levels, measuring currents up to 25 A. We identify recurrent geomagnetic activity in the measurements, and also find man-made sources of low frequency currents using frequency analysis. We focus on two geomagnetic storms from September 2017 and May 2021 to discuss the effects of GICs on a mid-latitude power transmission grid. In conclusion, we find that there is a daily level of noise in the data and that, even during the largest events when 14 A were measured, transformer heating remains unlikely.

How to cite: Bailey, R., Schachinger, P., Albert, D., Achleitner, G., and Leonhardt, R.: Analysis of six years of GIC measurements in the Austrian power grid, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6199, https://doi.org/10.5194/egusphere-egu23-6199, 2023.

James Wild, Cameron Patterson, and David Boteler

Studies of space weather impacts on ground-based infrastructure have largely focused on power networks and pipelines, but railway signalling systems are also affected, with misoperations observed in several countries. This paper advances recent theoretical work on geomagnetically induced currents in railway signalling systems by modeling realistic railway lines with parameters from current industrial standards. Focusing on two example lines in the United Kingdom with different locations and orientation, a range of uniform electric fields are simulated along each modelled line. The results show that misoperations could be caused by geomagnetic interference at disturbance levels expected to recur over timescales of several decades. We also demonstrate that the UK estimate for the geoelectric field induced by a 1 in 100-year extreme storm would be strong enough to cause widespread signal misoperations in both lines studied.

How to cite: Wild, J., Patterson, C., and Boteler, D.: Modeling the Impact of Geomagnetically Induced Currents on Electrified Railway Signalling Systems in the United Kingdom, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9660, https://doi.org/10.5194/egusphere-egu23-9660, 2023.

Adamantia Zoe Boutsi, Georgios Balasis, Stavros Dimitrakoudis, Ioannis A. Daglis, Kanaris Tsinganos, Constantinos Papadimitriou, and Omiros Giannakis

Geomagnetically Induced Currents (GIC) constitute an integral part of space weather research and are a subject of ever-growing attention for countries located in the low and middle latitudes. A series of recent studies highlights the importance of considering GIC risks for the Mediterranean region. Here, we exploit data from the HellENIc GeoMagnetic Array (ENIGMA), which is deployed in Greece, complemented by magnetic observatories in the Mediterranean region (Italy, France, Spain, Algeria and Turkey), to calculate values of the GIC index, i.e., a proxy of the geoelectric field calculated entirely from geomagnetic field variations. We perform our analysis for the most intense magnetic storms (Dst < -150 nT) of solar cycle 24. Our results show that GIC index increases are well correlated with Storm Sudden Commencements (SSCs). However, the GIC indices do not exceed “low” activity levels despite the increases in their values, at all magnetic stations / observatories under study during the selected storm events.

How to cite: Boutsi, A. Z., Balasis, G., Dimitrakoudis, S., Daglis, I. A., Tsinganos, K., Papadimitriou, C., and Giannakis, O.: Investigation of the Geomagnetically Induced Current Index levels in the Mediterranean region during the strongest magnetic storms of solar cycle 24, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3980, https://doi.org/10.5194/egusphere-egu23-3980, 2023.

Posters virtual: Wed, 26 Apr, 14:00–15:45 | vHall TS/EMRP

Chairperson: Ciaran Beggan
Ewelina Florczak, Ciaran Beggan, and Ellen Clarke

Dedicated scientific measurements of the strength and direction of the Earth's field began at Greenwich and Kew observatories in London, UK, in the middle of the 19th century. Using advanced techniques for the time, light-sensitive photographic paper and light-levered reflections from magnetized needles allowed continuous analogue magnetograms to be recorded. By good fortune, both observatories were in full operation during the so-called Carrington storm in late August/early September 1859 providing as complete a record as possible. Based on digital images of the magnetograms and information from the observatory yearbooks and scientific papers scaling the measurements to SI units is possible at minute-mean cadence. However, due to the magnitude of the storm, periods of the greatest magnetic field variation are lost as the traces moved off-page. We present the most complete digitized magnetic records to date of the ten-day period from 25th August to 5th September 1859 encompassing the Carrington storm and its precursor on the 28th August.

How to cite: Florczak, E., Beggan, C., and Clarke, E.: Digitizing the Carrington 1859 storm: magnetogram records from Greenwich and Kew observatories, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6191, https://doi.org/10.5194/egusphere-egu23-6191, 2023.

Sebastian Hölz, Magnar Gullikstad Johnsen, Gesa Franz, Fernando Córdoba Ramírez, Graeme Cairns, Mladen Nedimovic, Marion Jegen, Christian Berndt, Judith Elger, and Vittorio Maselli

In the marine environment, active and passive electromagnetic (EM) measurements are used to derive information about the conductivity structure beneath the seafloor. While the conductivity is mostly determined by the conductive seawater contained in the pore space or fractures, anomalies may occur in the presence of more resistive (e.g. hydrocarbons, free gas, gas hydrates, freshened water) or conductive materials (e.g. massive sulfides, brines). For the correct interpretation of EM data it is important to know the measurement geometry, including the orientations of receivers. From an experimental standpoint, this can be challenging because stations are often deployed free falling, thus, ending up in arbitrary orientations on the seafloor. The orientations are frequently derived from electronic compass measurements or magnetometers which record all components of the magnetic field. However, these measurements may be distorted by magnetic parts on stations (e.g. batteries), biased by local inhomogeneities in the local field or difficult to perform if no reliable reference data from a nearby observatory is available.

A possible remedy for such problems may come from space physics. Given a grid of stationary magnetometer stations, surrounding the area of interest but at relatively large distances, the method of spherical elementary current systems (SECS) (Amm & Viljanen, 1999, Earth, Plants and Space) can be used to reconstruct equivalent ionospheric currents and their resulting time variations of the magnetic field at any point within the grid. The method is especially suitable to be applied at northern latitudes, where fairly dense magnetometer networks such as IMAGE and CARISMA exist, and where the magnitude of geomagnetic disturbances from ionospheric currents is significant.

We have successfully applied the method to three marine EM data sets, one offshore Iceland, one in the arctic section of the North Atlantic (Loki's Castle) and one off the Canadian coast (Prince Edward Island). The SECS method qualitatively reproduces the magnetic variation as observed by the seafloor stations. Here we investigate the results from the above mentioned EM data sets, and discuss the applicability, accuracy and constraints of the SECS method for EM data calibrations. Furthermore, we illuminate the possibility for using SECS as an interpolation tool for other applications at remote offshore locations, such as measurement while drilling (MWD) operations.

How to cite: Hölz, S., Johnsen, M. G., Franz, G., Córdoba Ramírez, F., Cairns, G., Nedimovic, M., Jegen, M., Berndt, C., Elger, J., and Maselli, V.: Determination of orientation of marine magnetometers by means of modelled local field variations derived from spherical elementary current systems, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1288, https://doi.org/10.5194/egusphere-egu23-1288, 2023.

Chigomezyo Ngwira, Robert Arritt, and Charles Perry

Human technology is vulnerable to space weather, a natural hazard. High-voltage electric power transmission grids constitute one of the most critical man-made technological systems vulnerable to space weather driven geomagnetically induced currents (GICs). In this study, we perform an analysis of (1) measured GIC data collected at mid-latitudes by U.S. power utilities during the period from 2010 to 2021, and (2) the corresponding geomagnetic field information for each event. The study includes a statistical analysis of all events and an overview of the top three highest GIC recordings in the data. We show that roughly 80% of the events are associated with the main phase of geomagnetic storms, while about 20% are associated with sudden storm commencement.

How to cite: Ngwira, C., Arritt, R., and Perry, C.: Analysis of geomagnetically induced currents over the continental United States, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10912, https://doi.org/10.5194/egusphere-egu23-10912, 2023.