Modelling of geomagnetically induced currents in the Czech transmission grid

Abstract

We investigate the maximum expected magnitudes of the geomagnetically induced currents (GICs) in the Czech transmission power network. We compute a model utilising the Lehtinen–Pirjola method, considering the plane-wave model of the geoelectric field, and using the transmission network parameters kindly provided by the operator. We find that the maximum amplitudes expected in the nodes of the Czech transmission grid during the Halloween storm-like event are about 15 A. For the “extreme-storm” conditions with a 1-V/km geoelectric field, the expected maxima do not exceed 40 A. We speculate that the recently proven statistical correlation between the increased geomagnetic activity and anomaly rate in the power grid may be due to the repeated exposure of the devices to the low-amplitude GICs. Graphical Abstract

Analysis of Large Geomagnetically Induced Currents During the 7–8 September 2017 Storm: Geoelectric Field Mapping

“…Our modeling is able to reproduce the GICs measurements in MAN, with the correlation coefficient of ∼0.88 (Event I) and ∼0.84 (Event II) for measured (red line) and modeled (black line). GIC values during the geomagnetic storms are usually in the order of tens of amperes (e.g., Švanda et al., 2021; Torta et al., 2021) and our results confirms these observation (we do not observe values higher than 100 A). Moreover, GICs computations correspond to values mentioned for mid‐latitudes by (e.g., Albert et al., 2022; Bailey et al., 2022).…”

“…Moreover, geoelectric field mapping from Section 4, in particular the regions with strong values of E, denoted by red dark color, state independent confirmation of previous observations that the North Europe is the most likely area of large geoelectric fields (e.g., Viljanen et al, 2014). On the other hand, we see that significant geoelectric field disturbances may also occur at much lower latitudes, indicating the possibility of GIC problems there too (Beggan et al, 2021;Gil et al, 2021;Piersanti et al, 2020;Švanda et al, 2021;Torta et al, 2021). When the situation on the maps presented in Section 4 and in the form of the Supporting Information S1 is compared with GIC measurements in Mäntsälä, a good qualitative agreement is apparent.…”

“…It would be interesting to apply GEDMap in this context. Moreover, the GIC problems at middle-and low-latitude transmission lines have increasingly gained attention (e.g., Albert et al, 2022;Bailey et al, 2022;Barbosa et al, 2015;Švanda et al, 2021;Torta et al, 2012;Tozzi et al, 2019;Zois, 2013). In the light of this task proposed procedure of the geoelectric field mapping, not based on SECS methods (appropriate for high latitudes) can be tested and applied.…”

“…Moreover, it is worth noting, that the 1‐D model is fast and accurate at a single location (Beggan et al., 2021), which is the case for this study. Since we use a local conditions of 1‐D model, with a relatively dense net of magnetometers, one may assume that geoelectric field can be estimated only from geomagnetic field variations, without ionospheric current considerations (compare, e.g., Švanda et al., 2021).…”

“…The importance of the regional variability of geomagnetic disturbances was very often emphasized (e.g., Boteler, 2021; Dimmock et al., 2020; Švanda et al., 2021; Torta et al., 2021; Viljanen & Pirjola, 2017). Nevertheless, the sparse distribution of magnetometer stations demanded the application of the interpolation of the geomagnetic field.…”