110kV XLPE电缆绝缘层内应力的测试方法与分析

Test Methods and Analysis of Internal Stress in Insulating Layer of 110 kV XLPE Cable

以110 k V XLPE电缆为研究对象,分析了XLPE电缆的绝缘层内应力的产生原因,然后对采用不同工艺生产的两种高压XLPE电缆A1和A2热处理前后的XLPE绝缘层进行X射线衍射法(XRD)分析,通过比较衍射峰参数的差异,分析晶面和晶面间距的变化规律,并计算得出XLPE绝缘层中的内应力。结果表明:XLPE电缆A1在两个晶面处的晶粒数目多于A2;电缆A1中的内应力为压应力,内层压应力最大,外层压应力最小;电缆A2中的内应力为拉应力,内层拉应力最大,中层拉应力最小。实验证明基于X射线衍射法分析检测绝缘层中内应力的方法是可行的。

An 110kV XLPE cable was used to investigate the cause of internal stress in insulating layer of XLPE cable. The insulating layers of two high voltage XLPE cables （marked as A1 and A2, respectively） produced by different techniques before and after thermal treatment were analyzed by XRD. The change rule of crystal plane and interplanar spacing was studied by comparing the differences of diffraction peaks, and then the internal stress in XLPE insulating layer was calculated. The results show that the crystal number of cable A1 is larger than that of cable A2 at two crystal planes. The internal stress of cable A1 is compressive stress, the compressive stress of the inner layer is the largest, and the com- pressive stress of the outer layer is the smallest. The internal stress of cable A2 is tensile stress, the tensile stress of the inner layer is the largest, and the tensile stress of the middle layer is the smallest. The research proves that it is feasible to use XRD to study and test the internal stress in insulating layer.