Abstract

In power cables with sector current-carrying strands (SCSs), impregnated with paper insulation, there is a tangential electric field component along the layers. The permissible electric strength along the paper tapes is about ten times less than in the normal direction, which is taken into account when developing three-wire power cables impregnated with paper insulation for voltages of 20 and 35 kV. The use of modern paper—plastic-impregnated insulation having higher performance characteristics than conventional impregnated paper insulation, can promote the creation of more efficient cable designs with individually shielded sector-shape conductors in a common lead sheath for a voltage of 20 kV. Each insulated strand of such cables has a copper shield, and so it is enough to consider the electric field in the cross section of the insulation of one SCS. The electric potential distribution is described by the Laplace differential equation, the solution of which is implemented by the finite element method using the Ansys Maxwell software package. A numerical study of the electric fields has been carried out for power cables with SCSs that have a cross section of 400 mm² for a voltage of 20 kV. The curvature radius of the cable sectors varied from 5 to 7 mm with an insulation thickness of 7 to 9 mm. Based on the research results, the maximum values of the normal and tangential electric field components depending on the curvature radius of the sector strand and insulation thickness have been obtained. Insulation areas have been allocated in which the maximum absolute values of the tangential electric field strength components have been observed. The allowable values of the sector curvature radius and the thickness of insulation for power cables with paper-impregnated insulation for 20 kV have been determined.

中文翻译：

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带电压为20 kV的扇形绞合和浸渍纸-塑料绝缘的电力电缆电场的数值研究

摘要

在带有纸绝缘层的，带有扇形载流子线（SCS）的电力电缆中，沿各层存在切向电场分量。沿着纸带的允许的电气强度大约是法线方向的十倍，这在开发浸渍有纸绝缘层的三线电力电缆（电压为20和35 kV）时要考虑到。使用具有比常规浸渍纸绝缘材料更高的性能特征的现代纸塑浸渍绝缘材料，可以促进在20 kV电压的公共引线护套中使用单独屏蔽的扇形导体来创建更有效的电缆设计。此类电缆的每根绝缘线都带有铜屏蔽，因此，考虑一个SCS绝缘层横截面中的电场就足够了。电势分布由拉普拉斯微分方程描述，该方程的解是使用Ansys Maxwell软件包通过有限元方法实现的。已经对横截面为400 mm的SCS的电力电缆进行了电场的数值研究²电压为20 kV。电缆扇区的曲率半径从5到7 mm不等，绝缘厚度为7到9 mm。根据研究结果，获得了取决于扇形线股的曲率半径和绝缘厚度的法向和切向电场分量的最大值。已经分配了绝缘区域，在绝缘区域中已观察到切向电场强度分量的最大绝对值。确定了纸绝缘为20 kV的电力电缆的扇形曲率半径和绝缘厚度的允许值。