On 16.6.2022, the research team of FEEIT has successfully completed the scientific research project “Electromagnetic modeling of transient phenomena in large systems”, financed by the integrative funds of UKIM for 2020/2021.
The research work in the project is a continuation of the long-term research of a part of the project team, which was aimed at developing a model for the analysis of transient electromagnetic phenomena in large grounding systems in layered earth. During these researches, an electromagnetic model was developed which is based on the application of exact electromagnetic theory and which is set on a minimal approximations compared to other models for this purpose. The model enables high-accuracy analyzes that are of particular importance for the protection of people and equipment in contact with grounded structures, as well as for the protection of sensitive digital equipment from interference that can be transmitted through grounding systems. However, the high accuracy of the model imposes the need for significant computational resources, which is one of the main disadvantages of the model for its practical application in large grounding systems.
The research in this research project was aimed at improving the existing electromagnetic model, with the aim of achieving:
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Increased computational efficiency of the electromagnetic model through:
– optimization of the code and application of more computationally efficient numerical methods in the core of the electromagnetic model;
– application of algorithms for parallelization of calculations on multiple computers, on processors with multiple cores or with the help of graphic processors.
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Expanding the domain of application of the exact electromagnetic model through:
– introducing a mathematical exact model for insulated conductors such as cables, insulated pipelines, etc.;
– introduction of different forms of impulse excitation, as well as forms of excitation corresponding to transients and disturbances in the electric power systems;
The following results emerged from the research carried out within the scientific research project:
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By applying optimization methods and more efficient numerical methods, a reduction of the need for memory resources and greater computational efficiency of the model has been achieved. Depending on the analyzed problem, it is possible to reduce the calculation time up to several hundreds times in relation to the direct numerical solution of the integral equations that are in the core of the electromagnetic model, without introducing a significant error in the results.
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A tool has been developed for the rapid preparation of input data for extensive parametric analyzes and simultaneous distributed execution of the analyzes on several computers. By applying this tool, the duration of the preparation of the input data and processing of the obtained results was significantly shortened, that is, it was reduced from several days to a few minutes. Extensive parametric analyzes were performed simultaneously on more than 90 high-performance processors, allowing calculations that would normally take weeks on a single computer to be efficiently performed in less than 24 hours.
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A simplified code for the analysis of low-frequency grounding systems has been developed, which runs on a graphical processors. This research helped to establish directions for the parallelization of the significantly more complex electromagnetic model.
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Expansion of the application domain of the electromagnetic model was achieved by introducing an accurate model for insulated conductors such as cables, insulated pipelines, etc., with different electrical and magnetic characteristics. This expansion of the application domain contributed to new fields of research and publication of the obtained results, as well as to increased application in practical studies of electromagnetic influences in energy systems.
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The increased computational efficiency and expanded application possibilities enabled the application of the model in solving practical problems related to electromagnetic influences in large systems, as well as strengthening and expanding the established cooperation with companies from the energy sector, which was one of the more significant goals of the project. Within the duration of the project, with the application of the improved electromagnetic model, 4 reports for electromagnetic influences in energy systems were prepared.
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Two young researchers were included in the research team, and other external researchers joined the research, including a master’s degree student, whose research work resulted in the publication of results in a paper at an international conference. With this, another important goal of the project was achieved, that is the introduction of young researchers into current fields of scientific research, but also the expansion and increase of cooperation with research groups from other related fields of research.
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The results of the project were published in six scientific papers, three of which were published in international journals with an impact factor:
[1] L. Grcev, B. Markovski, M. Todorovski, “General Formulas for Lightning Impulse Impedance of Horizontal and Vertical Grounding Electrodes”, IEEE Transactions on Power Delivery, Vol. 36, No. 4, pp. 2245-2248, Aug. 2021. (IF 4.285 )
[2] L. Grcev, B. Markovski, M. Todorovski, “Lightning Performance of Multiple Horizontal, Vertical and Inclined Grounding Electrodes”, IEEE Transactions on Power Delivery (Early Access), DOI: 10.1109/TPWRD.2021.3137361, Dec. 2021. (IF 4.285 )
[3] B. Glushica, B. Markovski, A. Kuhar, V. Arnautovski-Toseva, “Assessment of Electric and Magnetic Field Exposure Near Overhead Transmission Lines Using 2D Finite Elements Method”, The 8th International Symposium on Applied Electromagnetics – SAEM’2022, Struga, Macedonia, 26-29 June 2022.
[4] B. Markovski, L. Grcev, V. Gjorgievski, B. Velkovski, M. Markovska Dimitrovska, “Electromagnetic Coupling of Overhead High Voltage Transmission Lines to Pipelines in Multilayer Soil: Parametric Analysis”, The 8th International Symposium on Applied Electromagnetics – SAEM’2022, Struga, Macedonia, 26-29 June 2022.
[5] B. Velkovski, B. Markovski, V. Gjorgievski, M. Markovska, L. Grcev, “Improving the Efficiency of Grounding System Analysis Using GPU Parallelization”, Conference Proceedings of XV International Conference ETAI 2021, pp. 218-222, 23-24.09.2021, Online Conference.
[6] L. Grcev, B. Markovski, M. Todorovski, “Lightning Efficient Counterpoise Configurations for Transmission Line Grounding”, IEEE PES Transactions on Power Delivery (Early Access), DOI: 10.1109/TPWRD.2022.3200579, Aug. 2022. (IF 4.285)
A research team with the following composition was involved in the implementation of the project:
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Asst. Prof. Blagoja Markovski – main researched
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Acad. Leonid Grcev – researcher
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Assist. Prof. d-r Marija Markovska – researcher
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Asst. Prof. Vladimir Gjorgiervski – researcher
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Asst. Bodan Velkovski – researcher
