Speaker
Description
Geomagnetically Induced Currents (GICs) may pose significant risks to power transmission systems during geomagnetic storms, making their study a uniquely interdisciplinary challenge at the intersection of space weather, geophysics, and power engineering. This work investigates the influence of shield wires (ShW), which are grounded conductors installed along transmission lines, on GIC simulations in realistic power networks. We develop and implement a simulation framework modified from GEOMAGICA, ShW-MAGICA, which incorporates ShW equivalents into the electric circuit model. Using the Portuguese high-voltage network as a case study, we evaluate the impact of including ShW over a range of different geophysical conditions, including both uniform and space-dependent conductivity models, as well as constant and time-dependent driving source fields. In particular, simulations are conducted using different conductivity models: a uniform half-space, idealised 2D resistivity discontinuities (north-south and west-east), and a detailed 3D model derived from magnetotelluric surveys. Regarding a realistic driving signal, we consider the June 22, 2015, geomagnetic storm.
We find that spatial heterogeneities in Earth’s conductivity have a greater influence on ShW-related GIC effects than temporal variations in the geomagnetic field, highlighting the importance of accurate characterisation of the subsurface geophysical parameters.
These results demonstrate that realistic GIC risk assessment requires an integrated approach, accounting for the physical properties of the power grid, the complex conductivity structure of the subsurface, and the dynamic drivers of space weather.
