Comparison Research on Electrical and Mechanical Properties of 110 kV High Voltage AC Cables with Smooth and Corrugated Aluminum Sheath Structures

In recent years, high⁃voltage AC cables frequently have failures due to ablation of the buffer layer in China. However, such failure is very rare in Europe. The research shows that the main reason is that the cables in China use corrugated aluminum sheath structure , while the smooth aluminum sheath structure is used in Europe. In order to fully understand the performance difference of corrugated and smooth aluminum sheath in cables, in this paper the ablation experiments for different sheath structures is performed firstly. Then, the magnitude of current density of different sheath structures is simulated through electric field simulation. Finally, the mechanical properties of the smooth aluminum sheath is tested. The results show that under the same ablation conditions, the cable with the corrugated aluminum sheathed structure is more prone to the ablation of the buffer layer due to the radial current concentration, while the cable with smooth aluminum structure is not prone to the ablation of the buffer layer because the aluminum sheath and the buffer layer are closely fitted without current concentration. The yield strength, tensile strength and elongation at break of the aluminum tube material are reduced after the smooth aluminum tube is bent after being stressed, which indicates that the mechanical properties of the aluminum tube are reduced after bending. Due to stress. Therefore, in practical projects, the use of the cable with smooth aluminum structure canvoid the occurrence of cable ablation, but it is necessary to avoid the degradation of mechanical properties due to large bending of the cable.