Effect of Geomagnetic Induced Current in Ethiopian Power Grid

Senbato, Ganebo Yared; Liu, Chunming; Wang, Hongmei

doi:10.12783/dtcse/icmsa2018/23290

Cited by 3 publications

(3 citation statements)

References 10 publications

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“…Unfortunately, the Chinese MT data are not openly available to the international research community. Senbato et al (2018) and Liu et al (2018a) developed a full node modeling of GICs in Ethiopia based on the Ethiopian power grid system model. A subset of 11 geomagnetic storms between the years 2003 and 2017 has been analyzed statistically, and the high-and low-probability extreme GIC values were estimated, with the low-probability extremevalue GIC exceeding 20 A at 89% of substations.…”

Section: Chinamentioning

confidence: 99%

The Role of Global/Regional Earth Conductivity Models in Natural Geomagnetic Hazard Mitigation

Kelbert

2019

Surv Geophys

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Geomagnetic disturbances cause perturbations in the Earth's magnetic field which, by the principle of electromagnetic induction, in turn cause electric currents to flow in the Earth. These geomagnetically induced currents (GICs) also enter man-made technological conductors that are grounded; notably, telegraph systems, submarine cables and pipelines, and, perhaps most significantly, electric power grids, where transformer groundings at power grid substations serve as entry points for GICs. The strength of the GICs that flow through a transformer depends on multiple factors, including the spatiotemporal signature of the geomagnetic disturbance, the geometry and specifications of the power grid, and the electrical conductivity structure of the Earth's subsurface. Strong GICs are hazardous to power grids and other infrastructure; for example, they can severely damage transformers and thereby cause extensive blackouts. Extreme space weather is therefore hazardous to man-made technologies. The phenomena of extreme geomagnetic disturbances, including storms and substorms, and their effects on human activity are commonly referred to as geomagnetic hazards. Here, we provide a review of relevant GIC studies from around the world and describe their common and unique features, while focusing especially on the effects that the Earth's electrical conductivity has on the GICs flowing in the electric power grids.

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Section: Chinamentioning

confidence: 99%

The Role of Global/Regional Earth Conductivity Models in Natural Geomagnetic Hazard Mitigation

Kelbert

2019

Surv Geophys

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“…Such GIC risk assessment analysis based on hypothetical or historical storms has been implemented both by the power grid utilities in‐house with the use of their proprietary system grid configuration models using generic, generally commercial, power grid modeling software, and in the academic literature, using approximate grid system configurations and, generally, homemade or open source modeling packages. These studies achieve different levels of modeling complexity, ranging from the use of a half‐space or 1‐D Earth assumption (e.g., Viljanen et al., 2014, in Europe; de Silva Barbosa et al., 2015, in Brazil; and Liu, Ganebo, et al., 2018; Senbato et al., 2018, in Ethiopia), to the use of a compilation of 1‐D Earth models (e.g., Liu et al., 2014, in China; Marti et al., 2014, in Canada; Caraballo, 2016, in Uruguay; Blake et al., 2016, in Ireland; Kelly et al., 2017, in the United Kingdom and France; and Espinosa et al., 2019, in Brazil), to the laterally heterogeneous thin‐sheet overlaying a 1‐D profiles (Beggan, 2015, in the United Kingdom; Divett et al., 2017, in New Zealand; Nakamura et al., 2018, in Japan; and Bailey et al., 2018, in Austria), and 3‐D Earth models (Rosenqvist & Hall, 2019, in Sweden; Liu, Wang, et al., 2018, in China; and Marshall et al., 2019, in Australia), the latter all recent developments (see Kelbert, 2020, for a detailed discussion). Here, a 1‐D Earth refers to the assumption that the Earth's conductivity is laterally homogeneous and varies only with depth, whereas 3‐D Earth models make no such assumption.…”

Section: Introductionmentioning

confidence: 99%

Modified GIC Estimation Using 3‐D Earth Conductivity

Kelbert

Lucas

2020

Space Weather

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Geomagnetically induced currents (GICs) are quasi‐direct current (DC) electric currents that flow in technological conductors during geomagnetic storms. Extreme GICs are hazardous to man‐made infrastructure. GICs enter and exit the technological systems, such as the electric power grid, at grounding points, and their magnitudes depend on the currents that flow underground. They are, therefore, a function of the Earth's electrical conductivity, represented at ground level as Earth impedances, as well as the resistance parameters of the power network. Traditional GIC estimation practices are based on Earth impedances obtained from laterally homogeneous or piecewise layered‐Earth models. We refer to these methods, collectively, as the 1‐D approximation. However, GIC hazard mitigation can be improved with more accurate GIC modeling that takes the spatially heterogeneous Earth's conductivity into account. Here, we propose a modified approximation for GIC estimation that is very similar to the 1‐D approximation but is instead derived from empirical 3‐D Earth impedances. Our formulation sets up the computation of static, frequency‐dependent power line telluric response functions, which, once computed, may be considered part of the power grid system model. These response functions may then be used for historical scenario analysis of GIC hazards and for simplified real‐time, albeit approximate, GIC estimation in a power grid. This modest modification to the simpler local field formulation approach avoids real‐time integration of geoelectric fields along power lines while taking the realistic 3‐D Earth into account in a rigorous manner. Once implemented, the method provides a power grid operator with the benefits of convenience and computational speed for a first look real‐time operational GIC hazard assessment. We estimate that the proposed modified 3‐D GIC modeling approach produces GIC values that are well within 50% of those obtained with the full‐scale power line integration of spatially variable geoelectric fields, for storms comparable in scale to the 2003 Halloween storm, all geological structures, and power lines located in the contiguous United States and other low‐ to middle‐latitude regions.

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“…In contrast to this concept, GICs were detected in several power systems in mid-low latitude countries, for example, South Africa [87], Spain [88] and New Zealand [54]. However, the 2003 GMD event has received attention and especially motivated GIC analysis in mid-low latitude countries, and as a result, many studies have been conducted, for example, on Argentina [89], Czech Republic [90], New Zealand [91][92][93][94] , Brazil [95][96][97], South Africa [98,99], China [100][101][102], Japan [103,104] , Kenya [105], Australia [106][107][108] , continental analysis of Europe [56], Spain [88,109], Switzerland [110], Greece [111], Namibia [112], Uruguay [113], Austria [114], Ethiopia [115,116], South Korea [117], Italy [118], and Mexico [119]. In high-latitude countries, the induced geoelectric field in the east-west direction is remarkable.…”

Section: Introductionmentioning

confidence: 99%

A Review of Geomagnetically Induced Current Effects on Electrical Power System: Principles and Theory

et al. 2020

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Geomagnetically induced current (GIC) has been a significant concern for the electrical power grid in high latitudes for decades. Its origin starts in the Sun; during extreme space weather, the magnetic field of the Earth varies rapidly. This variation induces electric fields at the Earth's surface and leads to GICs in manmade technologies. Power systems are the most affected by this induced current, which causes halfcycle saturation of power transformers and other issues. Understanding the behaviours and chain effects of this phenomenon is the key consideration in modelling the hazards to technological systems from space weather. In this paper, a comprehensive review of space weather, geomagnetic disturbances (GMDs) and GICs and their impacts on the power systems in both high and mid-low latitude regions is presented. Additionally, we highlight the most commonly used methods to model and calculate geoelectric fields at the Earth's surface and GIC in the power systems with respect to DC and AC analysis. In addition, we have classified the GIC effects on the different power system components. Moreover, the possible solutions and mitigation techniques to eliminate or reduce these effects based on different GIC blocking devices are reviewed in this work. This work provides researchers and power system operators a shortcut road path to understanding GIC phenomena, modelling and calculations, effects, and mitigation of these effects.

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Effect of Geomagnetic Induced Current in Ethiopian Power Grid

Cited by 3 publications

References 10 publications

The Role of Global/Regional Earth Conductivity Models in Natural Geomagnetic Hazard Mitigation

The Role of Global/Regional Earth Conductivity Models in Natural Geomagnetic Hazard Mitigation

Modified GIC Estimation Using 3‐D Earth Conductivity

A Review of Geomagnetically Induced Current Effects on Electrical Power System: Principles and Theory

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