Evaluation of low voltage on electrical cables using microct and COMSOL Multiphysics

• Published in: Radiation physics and chemistry (Oxford, England : 1993) Vol. 224; p. 112067
• Main Authors: da Silva, Marcus V.S., de Araújo, Olga M.O., dos Santos, Caio M.S.F.F., de Oliveira, Davi F., Freitas, Cleiton M., Lopes, Ricardo T.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2024
• Subjects: Electric arborescence; Electrical cables; Finite elements method; MicroCT; MicroCT; Finite elements method; Electric arborescence; Electrical cables
• ISSN: 0969-806X
• DOI: 10.1016/j.radphyschem.2024.112067

Safety and quality are critical challenges in electrical engineering and unscheduled system outages caused by device failures present a significant concern. One of its main causes is the presence of air voids in the insulating layer of power cables. The main objective of this work was to evaluate the effect of current pulses, which generally occurs in transients, on the proliferation of voids in the insulating layer of electrical cables. X-ray microtomography (microCT) was used in the identification and analysis of air voids in aluminum (Al) and copper (Cu) electrical cables, with different cross-sectional areas, before and after electrical current pulses. The results showed an increase in voids caused by current pulses and an increase in electromagnetic fields and temperature inside the conductor. Furthermore, it was observed that the current pulses applied to the cables increased the agglomeration of small imperfections in voids of larger diameters and it was possible to verify the phenomenon of electrical arborescence in the cable with the aluminum core, as well as modifications in the core of stranded cables. Soon after, the Comsol Multiphysics software was used, which uses the Finite Element Method (FEM), solving Maxwell's equations, to better understand the information accessed by the microCT technique that describes electromagnetic phenomena in power cables. The results showed that cables with a greater number of voids have higher electromagnetic field densities when compared to cables without voids in the insulation, showing an increase of 7.5, 10.16, and 9.91 for the copper cables of 25, 35 and 50 mm2, respectively. •It was possible to verify that pulses of electrical currents generate air voids within copper and aluminum electrical cables.•With the microCT tool, it was possible to characterize the air voids in terms of location, volume and void size distribution.•The phenomenon of electrical arborescence can be investigated in the insulating layer of aluminum electrical cable.•Electromagnetic simulations demonstrated that air voids cause variations in dissipated power and thermal energy.