Enter Zoom Meeting

EMRP2.13

EDI
Modelling and measuring Geomagnetically Induced Currents in grounded infrastructure

Geomagnetically Induced Currents (GICs) can damage grounded infrastructure such as high voltage transformers, 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 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.

Co-organized by ST2
Convener: Ciaran Beggan | Co-conveners: Adamantia Zoe BoutsiECSECS, Rachel L. BaileyECSECS
Presentations
| Wed, 25 May, 08:30–09:10 (CEST)
 
Room -2.31

Wed, 25 May, 08:30–10:00

Chairperson: Rachel L. Bailey

08:30–08:40
|
EGU22-6243
|
ECS
|
solicited
|
Highlight
|
Virtual presentation
Darcy Cordell et al.

Estimating the effect of geomagnetic disturbances on infrastructure is an important problem since they can induce damaging currents in electric power transmission lines. In this study, an array of magnetotelluric (MT) impedance measurements in Alberta and southeastern British Columbia are used to estimate the geoelectric field resulting from a magnetic storm on September 8, 2017. The resulting geoelectric field is compared to the geoelectric field calculated using the more common method involving a piecewise-continuous 1-D conductivity model. The 1-D model assumes horizontal layers, which result in orthogonal induced electric fields while the empirical MT impedance data account for fully 3-D electromagnetic induction. The geoelectric field derived from empirical MT impedance data demonstrates a preferential polarization in southern Alberta, and the geoelectric field magnitude is largest in northeastern Alberta where resistive Canadian Shield outcrops. The induced voltage in the Alberta transmission network is estimated to be ~120 V larger in northeastern Alberta when using the empirical MT impedances compared to the piecewise-continuous 1-D model. Transmission lines oriented northwest-southeast in southern Alberta have voltages which are 10-20% larger when using the MT impedances due to the polarized geoelectric field. As shown with forward modelling tests, the polarization is due to the Southern Alberta British Columbia conductor in the lower crust (20-30 km depth) that is associated with a Proterozoic tectonic suture zone. This forms an important link between ancient tectonic processes and modern-day geoelectric hazards that cannot be modelled with a 1-D analysis. The geoelectric field model and resulting line voltage is compared to differential magnetometer GIC measurements on one transmission line near the Heartland transformer in northeastern Alberta.

How to cite: Cordell, D., Unsworth, M., Lee, B., Hanneson, C., Milling, D., Parry, H., and Mann, I.: Estimating the Geoelectric Field, Transmission Line Voltages, and GICs During a Geomagnetic Storm in Alberta, Canada, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6243, https://doi.org/10.5194/egusphere-egu22-6243, 2022.

08:40–08:45
|
EGU22-6442
|
ECS
|
Virtual presentation
Adamantia Zoe Boutsi et al.

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 indices do not exceed low activity levels despite the increase in their values, at all magnetic observatories / stations under study during the selected storm events.

How to cite: Boutsi, A. Z., Balasis, G., Daglis, I. A., Tsinganos, K., and Giannakis, O.: Investigating the levels of Geomagnetically Induced Currents in the Mediterranean region during the most intense geomagnetic storms of solar cycle 24, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6442, https://doi.org/10.5194/egusphere-egu22-6442, 2022.

08:45–08:50
|
EGU22-3317
|
Virtual presentation
Kuralay Nurgaliyeva

In this research the analysis of shutdowns in long power line SS147AL169A in Almaty power grid for 2016-2021 was done. For the analyzed period, there were 16 emergency shutdowns. 6 of them occurred due to evident external causes. Other 10 cases analyzed for the possibility of a connection with the geomagnetic environment. Initial analysis showed a possible connection between the automatic operation of relay protection and the presence of geomagnetically induced currents. This is due to the geomagnetic situation, which was before the moment the relay was triggered. At the moment, more detailed calculations are being carried out.

This research has been/was/is funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP00000000).

How to cite: Nurgaliyeva, K.: Analysis of correlations between geomagnetic storms and emergency shutdowns in the part of Almaty power grid for 2016-2021, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3317, https://doi.org/10.5194/egusphere-egu22-3317, 2022.

08:50–08:55
|
EGU22-3006
|
ECS
|
Highlight
|
|
Virtual presentation
Cameron Patterson and Jim Wild

Track circuits are widely used signalling systems that use electrical currents to detect the presence or absence of a train in predefined sections of a railway network, as such, they are susceptible to interference from geomagnetically induced currents.

This work aims to determine the impact space weather has on realistic track circuits across geologically different regions of the UK under various storm conditions by using the Spherical Elementary Current System method of geomagnetic field interpolation, a ground conductivity model of the UK, a 1D-layered model to provide estimations of the geoelectric field and track circuit modelling techniques developed by Boteler (2021).

Early results of a modelled section of the West Coast Main Line in North West England will be presented.

How to cite: Patterson, C. and Wild, J.: Modelling space weather impacts on UK railway signalling systems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3006, https://doi.org/10.5194/egusphere-egu22-3006, 2022.

08:55–09:00
|
EGU22-3218
|
On-site presentation
James Wild et al.

It is well documented that space weather can impact electricity infrastructure, and several incidents have been observed in recent decades and directly linked to large geomagnetic storms (e.g. the Hydro Quebec incident in 1989). However, less is understood aboutthe impact of lower-level geomagnetically induced currents (GICs) on the health of transformers in the long term. In this study, the long term impact of geomagnetic activity  on 13 power station transformers in the UK is investigated. Dissolved gas measurements from 2010–2015 were used to look for evidence of a link between degradation of the transformer and heightened levels of the global SYM-H index and dB as measured at Eskdalemuir magnetometer station in southern Scotland. First, case studies of the most significant storms in this time period were examined using dissolved gas analysis (DGA) methods, specifically the Low Energy Degradation Triangle (LEDT). These case studies were then augmented with a statistical survey, including Superposed Epoch Analysis (SEA) of multiple storm events. No evidence of a systematic space weather impact can be found during this time period, likely owing to the relatively quiet nature of the Sun during this epoch and the modernity of the transformers studied.

How to cite: Wild, J., Lewis, Z., and Allcock, M.: Assessing the impact of weak and moderate geomagnetic storms on UK power station transformers, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3218, https://doi.org/10.5194/egusphere-egu22-3218, 2022.

09:00–09:05
|
EGU22-9495
|
Virtual presentation
Juliane Huebert et al.

Geomagnetically induced currents (GICs) have been identified as a hazard to the UK power grid and the security of electricity supply during severe geomagnetic storms. In order to monitor, model and forecast GICs, sophisticated models of the ground electric field and the network topology are required. We present a detailed analysis of differential magnetometer (DMM) and magnetotelluric (MT) data in the UK that allow the verification and validation of our network model for the UK power transmission grid. Combining the observation of line GICs measured with DMM in the past three years and the MT impedance tensor estimated at several locations in the UK shows an excellent fit of prediction and observation of GICs when using realistic modelled ground electric fields. This validates our whole network model allowing us to use it with confidence for real time and forecasting as well as extreme event analysis.

How to cite: Huebert, J., Beggan, C., Richardson, G., Gomez Perez, N., and Thomson, A.: Combining geoelectric field modelling and differential magnetometer data to validate GIC modelling in the UK High voltage power transmission grid, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9495, https://doi.org/10.5194/egusphere-egu22-9495, 2022.

09:05–09:10
|
EGU22-1769
|
On-site presentation
Sandra Chapman et al.

During geomagnetic storms rapid magnetic variations cause large, sharp enhancements of the magnetic and geoelectric field at mid-latitudes. These present a potential hazard to grounded technology such as high voltage transformers, pipelines and railway systems. Spatio-temporal quantification can provide insight into the magnitude and configuration of their potential hazard. We perform a wavelet decomposition on both European ground-based magnetometer measurements and modelled Geomagnetically Induced Currents (GICs) from the high voltage grid of Great Britain (GB).  A wavelet decomposition localizes the signal in the time-frequency domain, and we show that in both magnetometer observations, and modelled GIC response, the Haar wavelet extracts the signal power and waveform at the signal fastest rate-of-change.

We then use Haar wavelet cross-correlation of the GIC in the grounded nodes to build a time-varying network of GIC coherent response around the GB grid during intense geomagnetic storms [1]  including the 2003 Halloween storm. We find a highly intermittent (few 10s of minutes duration) long-range coherent response that can span the entire physical grid at most intense times. The spatial pattern of coherent response seen in the GIC flow network does not simply follow that of the amplitude of the rate of change of B field that is estimated via the Haar wavelet. Coherent response is excited across spatially extended clusters comprised of a subset of nodes that are highly connected to each other, with a tendency for east-west linkages following that of the physical grid, simultaneous with  the overhead presence of the auroral electrojet and the inducing component of the magnetic field. This can quantify the spatial and temporal location of increased hazard in specific regions during large storms by including effects of both the geophysical and engineering configuration of the high voltage grid.

[1] L. Orr, S. C. Chapman, C. Beggan, Wavelet and network analysis of magnetic field variation and geomagnetically induced currents during large storms, Space Weather (2021) doi: 10.1029/2021SW002772

 

How to cite: Chapman, S., Orr, L., and Beggan, C.: Wavelet cross-correlation dynamical network of the coherent GIC response to intense geomagnetic storms in the high voltage grid of Great Britain, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1769, https://doi.org/10.5194/egusphere-egu22-1769, 2022.