XLPE中压电缆中间接头的界面老化修复研究

Study on Interface Ageing Repairing of Intermediate Joints for XLPE Medium Voltage Cable

电缆中间接头是城市电缆系统中最容易出现问题的部位,为了提高老化后电缆中间接头的绝缘性能,本研究尝试通过向中间接头注入修复液的方法进行修复。首先在潮湿环境下对电缆中间接头进行电热加速老化试验,并向老化后的样本注入修复液进行修复,通过工频介质损耗测量、工频击穿试验和能谱分析对修复前后中间接头样本的结构和性能进行对比分析。结果表明:老化后电缆中间接头的绝缘强度明显下降,而通过修复液修复后其绝缘性能有所提升。通过能谱仪检测发现修复后中间接头界面出现了Si和Ti的氧化物,说明修复液可以扩散进入中间接头界面并与侵入的水汽反应生成有机聚合物,填充在界面气隙空腔位置,从而提高了中间接头的界面击穿电压,达到了修复电缆中间接头的目的。

The cable intermediate joint is the part where problems are most likely to occur in urban cable system. In order to improve the insulating properties of the aged cable intermediate joint, a repair fluid was injected into the intermediate joint to repair it. Firstly, the cable intermediate joint was conducted electrothermal accelerate ageing tests in humid environment, and then the aged sample was injected repair fluid. The structure and properties of the intermediate joint samples before and after repairing were compared by power frequency dielectric loss measurement, power frequency breakdown test, and energy spectrum analysis test. The results show that the insulation strength of the cable intermediate joint after ageing decreases significantly, and the insulating properties is improved after repairing by repair fluid. It is found by the energy dispersive spectrometer detection that there are Si and Ti oxides appeared on the interface of intermediate joint, which indicates that the repair fluid can diffuse into the interface of the cable intermediate joint and react with the moisture to form organic polymers filling the air gap cavity of interface, so as to increase the breakdown voltage of intermediate joint and achieve the purpose of repairing cable intermediate joint.