皱纹铝套变形对挤包绝缘直流电缆电场分布的影响

Influence of Deformed Corrugated Aluminum Sheath on the Electric Field of Extruded Insulation DC Cable

为研究高压直流电缆皱纹铝套受力变形对电缆绝缘结构造成的损伤,以及在运行过程中对电气性能的影响,针对500 kV直流电缆开展绝缘线芯热膨胀测试和皱纹铝套压扁试验,确定皱纹铝套变形在绝缘线芯表面造成的缺陷情况。建立有限元模型,分析绝缘场强分布随温差变化情况,以及皱纹铝套变形导致绝缘线芯表面缺陷后的场强分布情况。仿真结果表明:电缆在负载过程中绝缘场强随着绝缘温差的变化而变化,此外绝缘表面存在缺陷会进一步导致场强畸变,且畸变程度与外加电压和绝缘温差有关。

In order to determine the possible damage to the cable insulation structure by deformed corrugated aluminum sheath of HVDC cable and its influence on the electrical performance during operation, thermal expansion test and radial pressure test were conducted on 500 k V DC cable to identify the concave defects on insulation surface caused by the deformation of corrugated aluminum sheath. A finite element model was established to analyze the variation of insulation field intensity distribution with temperature drop, and the field intensity distribution on the defected insulation surface caused by the deformed corrugated aluminum sheath. The finite element simulation results show that the insulation field strength of cable varies with the insulation temperature difference during the load process, and the defects on the insulation surface can further cause the field strength distortion, the extent of which is related to the applied voltage and insulation temperature difference.