基于超低频介损检测的电缆绝缘性能评估与影响因素分析

Evaluation of Cable Insulation Performance and Analysis of Its Influence Factors Based on Ultra Low Frequency Dielectric Loss Detection

通过制定超低频介损检测方案与评判标准,应用超低频介损检测技术检测北京地区124条电缆的绝缘性能,并对异常状态的电缆进行解体分析。根据检测结果,从电缆投运年限与敷设方式两方面分析了电缆绝缘性能的影响因素。结果表明:在北京地区,大部分电缆绝缘故障由接头进水引起,运行初期的部分电缆由于安装不当等人为因素容易导致其绝缘损坏,运行末期的电缆由于水树枝老化等原因导致其绝缘性能相对较差;管井与隧道敷设方式存在影响电缆绝缘性能的问题,电缆绝缘老化相对严重。研究结果可为电缆绝缘性能的评估提供技术指导。

The ultralow frequency dielectric loss detection scheme and evaluation standard were formulated, the insulation performances of 124 cables in Beijing were detected by ultralow frequency dielectric loss technology, then the disintegration analysis was conducted on the abnormal state cable. According to the test results, the influencing factors of insulation performance of the cables were analyzed from the aspects of operation time and laying methods. The results show that in Beijing, most of the cable insula- tion faults are caused by the inlet of the joint, at the beginning of the operation, some cable insulations are easily damaged due to the improper installation and other human factors; at the end of the operation, the cable insulation performance is relatively poor because of water tree ageing. There are some prob-lems that affect the insulation performance of the cables in the ways of pipe laying and tunnel laying and the cable insulation were aged relatively severe. The research results can provide technical guidance for the evaluation of cable insulation performance.