硅氧烷对水树老化后的交联聚乙烯电缆的修复研究

Study of Siloxane Injection Technology on XLPE Cables for Water Tree Aging

采用了一种硅氧烷修复液对水树老化电缆进行绝缘修复,并对修复效果及水树尖端电场进行了分析和讨论。首先,采用水针电极加速老化系统对10kV交联聚乙烯(XLPE)电缆样本绝缘进行高频高压老化,直到电缆介质损耗因数达到20%左右。此后,通过压力注入式修复系统从老化样本缆芯注入修复液,修复液渗透进入绝缘进行修复。通过比较修复前后电缆介质损耗因数和击穿电压的变化,发现随着修复时间的延长,老化电缆的绝缘性能逐渐恢复到新电缆水平;同时,通过显微镜观察到水树空洞被反应生成的有机化合物有效填充,达到了消除绝缘层微孔中水分的效果。此外,通过修复液直接与水反应实验和电场有限元仿真结果,进一步证实该修复液能有效提升水树老化电缆的绝缘性能。结果表明,修复液能渗透到水树区并修复水树老化电缆。

In this paper,a siloxane fluid is used to rejuvenate the water tree aged XLPE cables,and the effect of the rejuvenation is also investigated.An accelerated aging experiment was performed with a water-needle electrode and a high frequency voltage generator to obtain water tree aged samples until the dielectric loss factor reached approximately 20%.The siloxane liquid was injected into aged cable samples with a pressure injection system.The dielectric loss factor and the breakdown voltage of the samples were compared before and after rejuvenation.Based on the result,the insulation level of the cable samples after rejuvenation is close to or higher than that of new cables.Also,through a microscope,the organic compounds created by the chemical reaction were observed to fill the micro voids of the water tree.Furthermore,the experiment of the direct reaction was performed between the siloxane fluid and water and the electric field distribution was analyzed by finite element method(FEM).According to the results,the siloxane fluid can enhance the insulation level of the aged cables.The experiment indicates that the siloxane liquid can diffuse into the water tree area and rejuvenate water tree aged cables.