电热联合老化对电缆附件应力锥处空间电荷积聚特性的影响

为研究电缆应力锥处电荷积聚效应,将10 kV交联聚乙烯电缆进行电热联合加速老化,采用电声脉冲法测试不同老化阶段的电缆应力锥处空间电荷在轴向和径向的分布规律。实验结果显示:空间电荷密度在距应力锥内侧边缘约2 cm位置最大,向轴向两侧逐渐减小;随着老化时间的增加,应力锥处的空间电荷密度逐渐增大,分布范围扩大。结合交流电压下电荷运输机制,分析得到电荷积聚的来源是空间电荷从外侧迁移至应力锥位置并发生积累。该研究可为电缆附件易发生故障原因分析提供理论参考,对于提升电缆绝缘性能具有重要现实意义和实用价值。

Effects of Electrical-thermal Aging on Space Charge Accumulation Characteristics at the Position of the Stress Cone in the Accessory

To research the distribution of space charge at the position of the stress cone in cable,a 10 kV XLPE cable was aged under electrical-thermal stress,and the distribution characteristics of space charge in the axial and radial direction of the cable at the stress cone were tested in different aging stages by a pulse electro-acoustic method.The test results show that,in the axial direction,the position of the maximum space charge density is at the inner edge of the cable stress cone,about 2 cm,and the charge density decreases in both inner and outer axial directions.With the increase of aging time,the space charge density at the stress cone gradually increases and its distribution range extends.According to the mechanism of charge transport under AC voltage,space charge migrates from the outside to the position of the stress cone and accumulates.The study of space charge accumulation at stress cone can provide a theoretical reference for the cause analysis of cable accessory failures.It is of important practical significance and value for the improvement of cable insulation properties.