525 kV挤包绝缘柔性直流海缆脱气时间研究

Study on Degassing Time of 525 kV Flexible DC Submarine Cable with Extruded Insulation

采用傅里叶红外光谱与直流特性测量方法研究了525 kV挤包绝缘柔性直流海缆的最佳脱气时间,分析了电缆绝缘层中不同位置绝缘的交联副产物相对含量、直流电导率、直流电气强度和平均空间电荷密度随脱气时间的变化规律。结果表明:脱气33 d后,不同位置绝缘的交联副产物含量与直流电性能均趋于稳定,525 kV挤包绝缘柔性直流海缆的脱气时间达到35 d时,即可获得较为稳定的脱气效果。未脱气时绝缘层不同位置的交联副产物含量及直流特性较为均一,脱气过程中内部绝缘的直流特性参数均劣于中部绝缘与外部绝缘。

The optimal degassing time of 525 kV flexible DC submarine cable with extruded insulation was studied using Fourier transform infrared spectroscopy and DC characteristics measurement methods, and the change laws of relative contents of crosslinking by-products, DC conductivity, DC electric strength, and average space charge density at different positions of cable insulation layer with degassing time were analyzed. The results show that both the contents of crosslinking by-products and DC electri- cal properties at different positions of insulation layer tend to be stable after degassing for 33 days. When the degassing time of 525 kV flexible DC submarine cable with extruded insulation attains 35 days, the degassing effect is relatively stable. The contents of crosslinking by-products and DC characteristics at different positions of insulation layer are more uniform before degassing treatment, and the DC characteristic parameters of inner insulation are inferior to those of middle and outer insulation during degassing process.