输电电缆外护层绝缘电阻偏低相关因素分析及建议

Analysis on Relevant Factors for Low Insulating Resistance of Outer Sheath of Transmission Cable and Corresponding Suggestions

为提高广州地区输电电缆运行的可靠性,研究影响输电电缆外护层绝缘电阻偏低的相关因素,并据此调整输电电缆运维策略。随机抽选110 kV、220 kV的电缆外护层绝缘电阻试验数据进行统计,分析研究不同因素与外护层绝缘电阻偏低的相关性。研究结果表明,电缆的投运年限、白蚁分布、敷设方式和外护层材料与电缆外护层绝缘电阻有明显的相关性,电缆投运后这些因素将会共同影响外护层的绝缘特性。提出关于电缆外护层设计、施工、运维的建议,包括:根据运行环境选择外护层材料,提高施工监管,将运行12年以上的电缆试验周期缩短到2年,发现绝缘电阻全相降低或金属环流异常时及时进行检修。

In order to improve operation reliability of power transmission cables in Guangzhou area, the paper studies relevant factors for low insulating resistance of outer sheath of the transmission cable and proposes to adjust operation and main-tenance strategy for the cable. On the basis of testing data about insulating resistance of outer scables selected by random, it analyzes and studies correlation between different factors and condition of low insulating resist-ance of the outer sheath. Research results indicate operating year , termite distribution , laying mode and material of the outer sheath all have significant correlation with insulating resistance of the outer sheath and these factors will jointly affect insulation performance of the outer sheath of the cable in operation. The paper proposes suggestions operation and maintenance of the outer sheath including choosing materials of the outer sheath according to operating envronment, improving construction supervision, shortening testing period of the cable having running for twelve years to two years and performing repair as all phases of the insulating resistance decrease or metal circulation is abnormal.