Synergistic Approach for Computational Analysis of Geomagnetically Induced Currents in Power Grids

Geomagnetically induced currents (GICs) have the potential to be highly disruptive to regular power grid operations. Despite the study of geomagnetic disturbances (GMDs) since the 1940s, comprehensive methods for accurate and precise analysis of their impact, especially in individual grid components, remain limited. This paper describes a method based on the synergistic use of different computational tools for detailed simulation of GMDs in power grids. The proposed methodology allows the effective integration between three main aspects required for accurate determination of GICs and their effects on power systems: (1) location-specific estimation of Earth's magnetic fields at ground level, (2) detailed physics-based ground impedance modeling considering specific geological environment, and (3) power grid modeling considering detailed network and grounding topology. The goal is to generate an end-to-end methodology for GIC calculation in power grids from the magnetic field environment during a geomagnetic event, the soil conductivity profile at the site of interest, and the grid topology data. The resulting methodology was evaluated by means of a sample case that utilizes magnetic field data from an actual event.

I. Introduction

Geomagnetic storms are a type of space weather event in which the Earth's magnetic field interacts with magnetic solar material [1], [2]. Variations in the Earth's magnetic field produced by this interaction result in electric field variations according to Faraday's law of induction. Furthermore, these electric fields give rise to low-frequency currents, known as geomagnetically induced currents (GIC) flowing along conducting paths of large extension, such as power transmission lines, pipelines, and railways [2]. In the case of transmission lines, GIC occurrence and impact has become substantially more significant over the last decades with the exponential growth in electric grids, as well as the trend towards the use of higher transmission voltages and lower line resistances to reduce transmission losses over long distances, which results in electric power systems that are more susceptible to GIC effects. GIC can affect various power components, such as transformers, generators, protection devices, grid communication systems, etc. Depending on the severity and duration of a geomagnetic event, the effects of GIC can range from minor fluctuations in the power grid to malfunctioning of protection devices, damage of power apparatus, and even complete power outages [3].