中压电缆中间接头受潮规律试验

Experiment on the Law of Moisture Migration in Medium Voltage Cable Joints

中压电缆中间接头受潮容易导致绝缘劣化,是线路异常和停电事故的重要原因。研究电缆中间接头受潮扩散路径,摸清接头引起水分入侵的部位具有重要的工程价值。通过不同接头样本加速受潮试验,研究了实际中间接头内部水分扩散规律,包括水分入侵部位、扩散路径。结果表明:中间接头内水分扩散是由外到内逐层渗透深入的过程;其中,防水胶带与电缆内外护套黏结性能下降和铠装连接线的存在是造成接头主体外部水分快速扩散的关键因素;中间接头主体内部交联聚乙烯(XLPE)和硅橡胶(SiR)复合界面水分扩散主要以轴向扩散为主。

Moisture migration in medium voltage cable joints can easily lead to insulation deterioration,which can cause power outages in serious cases.Therefore,it is of great engineering value to study the moisture diffusion path of cable joints and find out which parts of the joints are likely to cause moisture intrusion.The water diffusion law in the actual joint was studied through accelerated damping experiments of different joint samples,including water intrusion site and diffusion path.The results showed that water diffusion in the joint was a process of infiltration and in-depth layer by layer from the outside to the inside.Among them,the decline of the adhesion between waterproof tape and the inner and outer sheath of the cable and the existence of armored connecting wire were the key factors that caused the rapid diffusion of moisture outside the main body of the joint.Water diffusion at the composite interface of cross-linked ployethylene(XLPE)and silicone rubber(SiR)inside the main body of the joint was mainly axial diffusion.