The growing integration of DC technologies into modern electrical power grids results in increasing direct currents within the earth, originating from HVDC systems, geomagnetically induced currents, and parasitic currents from industrial converters. These DC currents can significantly impact grid operations, equipment, protection systems, and infrastructures, leading to increased network losses, transformer saturation effects, protection system malfunctions, and corrosion issues.
Reliable calculation methods are essential to realistically assess these impacts. Alongside analytical approaches, numerical methods such as the finite element method or resistance network models are commonly utilized. Studies show that realistic current distributions can only be calculated when soil heterogeneity and grounding geometry are accurately considered. However, normative gaps and open research questions remain in the context of DC currents in the ground, particularly regarding systemic long-term effects, improved measurement methods, and adapted protection strategies, which
must be addressed in future research.