Time Domain Simulation of Geomagnetically Induced Current (GIC) Flowing in 500‐kV Power Grid in Japan Including a Three‐Dimensional Ground Inhomogeneity

Abstract

We performed 3‐D time domain simulation of geomagnetically induced currents (GICs) flowing in the Japanese 500‐kV power grid. The three‐dimensional distribution of the geomagnetically induced electric field (GIE) was calculated by using the finite difference time domain method with a three‐dimensional electrical conductivity model constructed from a global relief model and a global map of sediment thickness. First, we imposed a uniform sheet current at 100‐km altitude with a sinusoidal perturbation to illuminate the influence of the structured ground conductivity on GIE and GIC. The simulation result shows that GIE exhibits localized, uneven distribution that can be attributed to charge accumulation due to the inhomogeneous conductivity below the Earth's surface. The charge accumulation becomes large when the conductivity gradient vector is parallel or antiparallel to the incident electric field. For given GIE, we calculated the GICs flowing in a simplified 500‐kV power grid network in Japan. The influence of the inhomogeneous ground conductivity on GIC appears to depend on a combination of the location of substations and the direction of the source current. Uneven distribution of the power grid system gives rise to intensification of the GICs flowing in remote areas where substations/power plants are distributed sparsely. Second, we imposed the sheet current with its intensity inferred from the ground magnetic disturbance for the magnetic storm of 27 May 2017. We compared the calculated GICs with the observed ones at substations around Tokyo and found a certain agreement when the uneven distribution of GIE is incorporated with the simulation.

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

“…It was previously mostly studied in the context of MT (Fischer & Weaver, 1986;Parkinson & Jones, 1979;Weaver & Dawson, 1992, among others) and geomagnetic depth sounding (Kuvshinov et al, 1999;Kuvshinov, 2008, among others) researches. This effect in the GEF was also discussed in a number of studies in connection with space weather research (Gilbert, 2005;Honkonen et al, 2018;Ivannikova et al, 2018;Liu et al, 2018;Nakamura et al, 2018;Püthe & Kuvshinov, 2013, among others). Usually, it is quantitatively assessed by comparing results of 3-D and 1-D computations, where 3-D modeling aims at reproducing effects from lateral ocean/land conductivity contrasts.…”

Geomagnetically Induced Current Model Validation From New Zealand's South Island

“…However, a more modern geoelectric model such as Püthe and Kuvshinov (2013) or Nakamura et al. (2018) would avoid this issue.…”

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

“…Finally, fully 3D modeling is rather rare in the modern GIC estimation landscape, but is coming into fashion as new MT surveys are being completed and the regional electrical conductivity models are obtained. Some examples include the recent work in Japan (Fujita et al 2018;Nakamura et al 2018;Fig. 6, left) and the modeling study by Ivannikova et al (2018) in the UK.…”

“…Overall, higher resolution modeling better informed by data is needed. Full GIC modeling in Japan is the next step, if the power grid system parameters can be acquired or approximated (Nakamura et al 2018).…”

“…The phenomena of space weather (e.g., Song et al 2001;Lanzerotti 2001;Moldwin 2008;Love et al 2014;Fujita et al 2016) have been observed to cause disruption in man-made technological systems for well over a century. The first paper on the impact of a geomagnetic disturbance on technological infrastructure, known to the author, appeared in 1849 in relation to space weather effects on telegraph systems (Barlow 1849).…”