Investigating the Impact of Soil Models on GPR in Wind Turbine Grounding Systems Across Various Geographical Regions

Heydari, Omid; Moradi, Hassan; Karimi, Shahram; Abdi, Hamdi

doi:10.61882/jgeri.3.1.1

Investigating the Impact of Soil Models on GPR in Wind Turbine Grounding Systems Across Various Geographical Regions

Document Type : Research article

Authors

Omid Heydari

Hassan Moradi

Shahram Karimi

Hamdi Abdi

Department of Electrical Engineering, Faculty of Engineering, Razi University, Kermanshah, 6714414971, Iran

10.61882/jgeri.3.1.1

Abstract

Grounding systems in wind turbines ‎are critical for lightning protection ‎and managing GPR. This study ‎investigates the influence of different ‎soil models (uniform, two-layer, and ‎three-layer) on GPR across six ‎distinct geographical regions: desert, ‎forest, agricultural, mountainous, ‎coastal, and frozen. Simulations were ‎performed using the CDEGS software ‎on a standard grounding system ‎comprising a ring electrode, ‎horizontal electrodes, and vertical ‎electrodes. The results reveal a strong ‎dependence of GPR on soil ‎characteristics and regional ‎conditions. In desert regions, the high ‎resistivity of dry soil significantly ‎increases GPR, whereas in coastal ‎areas, water-saturated layers ‎markedly reduce GPR. In frozen ‎regions, surface layer freezing ‎substantially elevates GPR despite ‎lower resistivity in deeper layers. The ‎study demonstrates that increasing ‎the complexity of the soil model (i.e., ‎the number of layers) does not ‎necessarily mitigate GPR, ‎underscoring the need for region-‎specific data in grounding system ‎design. Numerical results show the ‎largest peak GPR for the uniform ‎model in the frozen region during ‎winter (≈2,197,587 V), reduced to ‎‎802,833.2 V with the three-layer ‎model (≈63.5% reduction). Overall, in ‎high-resistivity regions (desert, ‎mountainous, frozen), multilayer ‎models yield substantial GPR ‎reductions, whereas in coastal areas, ‎changes in the soil model cause only ‎minor decreases (≈13.5%). These ‎findings highlight the importance of ‎tailoring grounding system designs to ‎geographical conditions, potentially ‎enhancing the safety and efficiency ‎of wind turbines against lightning ‎strikes‎‎‎‎.‎

Graphical Abstract

Investigating the Impact of Soil Models on GPR in Wind Turbine Grounding Systems Across Various Geographical Regions

Highlights

❖ Regional Dependence: GPR spikes in high-resistivity soils (desert, frozen) but remains low in water-saturated coastal areas.
❖ Model Efficiency: Multi-layer soil models drastically reduce predicted GPR in harsh regions (~63.5%) but offer minimal gains in coastal zones (~13.5%).
❖ Critical Reduction: In frozen terrain, realistic three-layer modeling cut peak GPR from ~2.2 MV to ~0.8 MV compared to uniform assumptions.
❖ Key Takeaway: Effective wind turbine grounding demands region-specific soil data rather than generic uniform models.

Keywords

Wind turbine Grounding System

Soil modeling

Lightning

CDEGS software

Geographical areas

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The ethical issues, including plagiarism, informed consent, misconduct, data fabrication and/or falsification, double publication and/or submission, redundancy, have been completely observed by the authors.

Credit Authorship Contribution Statement

Omid Heydari: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Validation, Writing - original draft. Hassan Moradi: Data curation Funding acquisition, Investigation, Supervision, Writing-review & editing. Shahram Karimi: Conceptualization, Formal analysis, Project administration, Resources, Supervision, Writing-review & editing. Hamdi Abdi: Conceptualization, Funding acquisition, Methodology, Supervision, Validation, Writing-original draft.

Bibliography

Omid Heydari was born in 1988 in the city of Ilam, Iran. He received his Bachelor’s degree in Electrical Engineering from the Islamic Azad University of Arak in 2011, followed by a Master’s degree in Power Electrical Engineering from the University of Ilam in 2017. Since 2019, he has been a Ph.D. student in Electrical Engineering at Razi University, Kermanshah, Iran. His academic interests are mainly focused on research and development in the field of lightning protection systems, particularly for electrical equipment such as wind turbines. His research activities aim to improve the reliability and protection of power and renewable energy systems against lightning-related hazards.

Hassan Moradi is an Associate Professor in the Department of Electrical Engineering at the Faculty of Engineering, Razi University, Kermanshah, Iran, where he has been a faculty member since 2011. He was born in Kermanshah, Iran, in 1979 and completed his Ph.D. in Electrical Engineering at Shahid Beheshti University, Tehran, Iran, earning his degree in 2011 before joining Razi University’s academic staff. At Razi University, Dr. Moradi teaches undergraduate and graduate courses and actively conducts research in key areas of electrical engineering, with particular emphasis on power systems, electrical machines, power electronics, microgrids, and advanced control strategies for modern energy systems. His research contributions include numerous peer-reviewed journal and conference publications focused on topics such as microgrid stability and control, HVDC systems, electromagnetic design of electric machines, power converter control, and energy system optimization, reflecting his extensive engagement with both theoretical and applied aspects of electrical engineering. Dr. Moradi’s work has been widely cited in the academic community, and he collaborates with researchers nationally and internationally to advance innovative solutions in power and energy engineering.

Shahram Karimi is an Assistant Professor in the Department of Electrical Engineering, Faculty of Engineering, Razi University, Kermanshah, Iran. He was born in Kermanshah, Iran, in 1972. He received his Bachelor’s degree in Electrical Engineering from the University of Tabriz in 1995, followed by a Master’s degree from Sharif University of Technology, Tehran, in 1997. He earned his Ph.D. in Electrical Engineering from Université Henri Poincaré (Nancy I), France, in 2008. After completing his doctoral studies, he joined Razi University, where he has been actively involved in teaching and research in the field of electrical engineering. His main research interests include power systems analysis and control, microgrids, voltage and frequency control, power quality, renewable energy integration, FACTS devices, and fault-tolerant power converters. Dr. Karimi has published numerous research papers in reputable national and international journals and conferences and has contributed significantly to the development of advanced control and optimization methods for modern power and energy systems.

Hamdi Abdi was born in Paveh, Iran, in July 1973. He received the B.Sc. degree from Tabriz University, Tabriz, Iran, in 1995, and the M.Sc. and Ph.D. degrees from Tarbiat Modares University, Tehran, Iran, in 1999 and 2006, respectively, all in electrical engineering. He is currently a Full Professor in the Department of Electrical Engineering, Razi University, Kermanshah, Iran. His research interests include power system operation and planning, smart energy systems, uncertainty management, and energy hub.

Citation

O. Heydari, H. Moradi, S. Karimi, and H. Abdi, "Investigating the Impact of Soil Models on GPR in Wind Turbine Grounding Systems Across Various Geographical Regions," Journal of Green Energy Research and Innovation, vol. 3, no. 1, pp. 1-15, 2026.