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.

中文翻译：

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使用 microct 和 COMSOL Multiphysics 评估电缆上的低电压


安全和质量是电气工程中的关键挑战，设备故障导致的计划外系统中断是一个重大问题。其主要原因之一是电力电缆绝缘层中存在气孔。这项工作的主要目的是评估电流脉冲（通常发生在瞬态）对电缆绝缘层中空隙扩散的影响。 X 射线显微断层扫描 (microCT) 用于识别和分析电流脉冲前后具有不同横截面积的铝 (Al) 和铜 (Cu) 电缆中的气孔。结果表明，电流脉冲导致空隙增加，导体内部电磁场和温度增加。此外，观察到施加到电缆上的电流脉冲增加了较大直径空隙中小缺陷的聚集，并且可以验证具有铝芯的电缆中的电树状现象以及芯的修改绞合电缆。不久之后，人们使用了 Comsol Multiphysics 软件，该软件使用有限元法 (FEM) 求解麦克斯韦方程组，以更好地理解通过 microCT 技术获取的描述电力电缆电磁现象的信息。结果表明，与绝缘体中没有空隙的电缆相比，具有较多空隙的电缆具有更高的电磁场密度，25、35 和 50 mm2 的铜电缆分别增加了 7.5、10.16 和 9.91。