Modelling geomagnetically induced currents in midlatitude Central Europe using a thin-sheet approach

Bailey, Roger C.; Halbedl, Thomas Stefan; Schattauer, Ingrid; Römer, A.; Achleitner, Georg; Beggan, Ciarán; Wesztergom, Viktor; Egli, Ramón; Leonhardt, Roman

doi:10.5194/angeo-35-751-2017

Cited by 58 publications

(62 citation statements)

References 39 publications

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“…BP17 then showed how this method could be used to demonstrate the influence of the geomagnetic coast effect on power networks using a hypothetical square network as well as for the test case network of Horton et al (2012). More recently, Richardson and Beggan (2017) confirmed that the LP85 method used to model GIC in the United Kingdom, Ireland, Austria, and New Zealand (Bailey et al, 2017;Beggan et al, 2013;Blake et al, 2016;Divett et al, 2017) correctly calculates the transformer-level current of the test case in Horton et al (2012). It is this implementation of LP85, which we extend in the present study.…”

Section: 1029/2018sw001814mentioning

confidence: 98%

“…Modeling GIC is useful to understand the impact of geomagnetic storms on power systems. A standard approach to modeling GIC, used, for example, by Koen and Gaunt (2003), Torta et al (2012), Beggan et al (2013), Blake et al (2016), Bailey et al (2017), and Divett et al (2017), has been to use the method of Lehtinen and Pirjola (1985;LP85 hereafter). In these applications of the LP85 method substations are approximated as a single resistance to Earth and it is usually assumed that equal levels of GIC flow through each transformer in a substation.…”

Section: Introductionmentioning

confidence: 99%

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Transformer‐Level Modeling of Geomagnetically Induced Currents in New Zealand's South Island

et al. 2018

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During space weather events, geomagnetically induced currents (GICs) can be induced in high‐voltage transmission networks, damaging individual transformers within substations. A common approach to modeling a transmission network has been to assume that every substation can be represented by a single resistance to Earth. We have extended that model by building a transformer‐level network representation of New Zealand's South Island transmission network. We represent every transformer winding at each earthed substation in the network by its known direct current resistance. Using this network representation significantly changes the GIC hazard assessment, compared to assessments based on the earlier assumption. Further, we have calculated the GIC flowing through a single phase of every individual transformer winding in the network. These transformer‐level GIC calculations show variation in GICs between transformers within a substation due to transformer characteristics and connections. The transformer‐level GIC calculations alter the hazard assessment by up to an order of magnitude in some places. In most cases the calculated GIC variations match measured variations in GIC flowing through the same transformers. This comparison with an extensive set of observations demonstrates the importance of transformer‐level GIC calculations in models used for hazard assessment.

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Section: 1029/2018sw001814mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Transformer‐Level Modeling of Geomagnetically Induced Currents in New Zealand's South Island

et al. 2018

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“…Computations of the GEF within the second, most populated, group of papers (Beggan et al, ; Bailey et al, , ; Divett et al, ; Dimmock et al, ; Liu et al, ; Marshall et al, ; Nakamura et al, ; Püthe & Kuvshinov, ; Püthe et al, ; Pokhrel et al, ; Rosenqvist & Hall, ; Wang et al, , among others) rely on a numerical modeling of the GEF, either with a thin sheet or fully 3‐D conductivity models of the Earth. 3‐D conductivity models can be compiled using, for instance, results of regional MT surveys or/and exploiting global and regional maps of bathymetry, sediment thickness, etc.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Influence of Lateral Conductivity Contrasts on the Storm Time Behavior of the Ground Electric Field in the Eastern United States

et al. 2020

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The intensification of the fluctuating geomagnetic field during space weather events leads to generation of a strong electric field in the conducting earth, which drives geomagnetically induced currents (GICs) in grounded technological systems. GICs can severely affect the functioning of such infrastructure. The ability to realistically model the ground electric field (GEF) is important for understanding the space weather impact on technological systems. We present the results of three‐dimensional (3‐D) modeling of the GEF for the eastern United States during a geomagnetic storm of March 2015. The external source responsible for the storm is constructed using a 3‐D magnetohydrodynamic (MHD) simulation of near‐Earth space. We explore effects from conductivity contrasts for various conductivity models of the region, including a 3‐D model obtained from inversion of EarthScope magnetotelluric data. As expected, the GEF in the region is subject to a strong coastal effect. Remarkably, effects from landmass conductivity inhomogeneities are comparable to the coastal effect. These inhomogeneities significantly affect the integrated GEF. This result is of special importance since the computation of GICs relies on integrals of the GEF (voltages), but not on the GEF itself. Finally, we compare the GEF induced by a laterally varying (MHD) source with that calculated using the plane wave approximation and show that the difference is perceptible even in the regions that are commonly considered to be negligibly affected by lateral nonuniformity of the source. Overall, the difference increases toward the north of the model where effects from laterally variable high‐latitude external currents become substantial.

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“…A quasi 3‐D approach that has been employed in a number of GIC studies is the thin sheet conductivity model (Vasseur & Weidelt, ), whereby conductivity gradients such as the ocean‐continent boundaries are included by employing a thin sheet conductance map overlying layered resistivity structures. This method has been used in GIC studies of power systems in the UK (Beamish et al, ; Beggan et al, ; Kelly et al, ; Thomson et al, ), France (Kelly et al, ), Austria (Bailey et al, , ), and New Zealand (Divett et al, , ). The thin‐sheet model is a period‐dependent model that requires satisfaction of a range of conditions, as discussed by Weaver (), and is physically viable for periods in a certain range.…”

Section: Introductionmentioning

confidence: 99%

Modeling Geomagnetically Induced Currents in Australian Power Networks Using Different Conductivity Models

et al. 2019

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Space weather manifests in power networks as quasi‐DC currents flowing in and out of the power system through the grounded neutrals of high‐voltage transformers, referred to as geomagnetically induced currents. This paper presents a comparison of modeled geomagnetically induced currents, determined using geoelectric fields derived from four different impedance models employing different conductivity structures, with geomagnetically induced current measurements from within the power system of the eastern states of Australia. The four different impedance models are a uniform conductivity model (UC), one‐dimensional n‐layered conductivity models (NU and NW), and a three‐dimensional conductivity model of the Australian region (3DM) from which magnetotelluric impedance tensors are calculated. The modeled 3DM tensors show good agreement with measured magnetotelluric tensors obtained from recently released data from the Australian Lithospheric Architecture Magnetotelluric Project. The four different impedance models are applied to a network model for four geomagnetic storms of solar cycle 24 and compared with observations from up to eight different locations within the network. The models are assessed using several statistical performance parameters. For correlation values greater than 0.8 and amplitude scale factors less than 2, the 3DM model performs better than the simpler conductivity models. When considering the model performance parameter, P, the highest individual P value was for the 3DM model. The implications of the results are discussed in terms of the underlying geological structures and the power network electrical parameters.

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Modelling geomagnetically induced currents in midlatitude Central Europe using a thin-sheet approach

Cited by 58 publications

References 39 publications

Transformer‐Level Modeling of Geomagnetically Induced Currents in New Zealand's South Island

Transformer‐Level Modeling of Geomagnetically Induced Currents in New Zealand's South Island

Exploring the Influence of Lateral Conductivity Contrasts on the Storm Time Behavior of the Ground Electric Field in the Eastern United States

Modeling Geomagnetically Induced Currents in Australian Power Networks Using Different Conductivity Models

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