发展在XLPE电缆绝缘内外侧的电树枝

以XLPE高压电力电缆内外侧绝缘中的电树枝特性为研究对象，通过分析电树枝引发与生长的统计实验规律和采用扫描电子显微镜分析发现，由于不同结晶状态的影响，电缆绝缘内外侧的电树枝特性存在很大的差异.引发于绝缘内侧电树枝引发时间短、生长速度快、电树枝形状具有多样性；起始于绝缘外侧的电树枝不仅引发时间长、生长速度极慢，而且电树枝形状(结构)比较单一.并对这两个位置电树枝的引发和生长机理进行了探讨. 关键词： 电树枝 结晶状态 统计规律 内侧和外侧绝缘层

The electrical trees that developed in inner and outer layer of XLPE cable insulation

Due to the limitations of specific insulation structures and the influence of technical process,the growth of electrical trees in high-voltage power equipments with polymer as main insulation materials is more complicated than those in uniform materials,especially in equipment employing semi-crystalline polymer,so it is difficult to characterize by mathematical means. The experiment reported in this paper is the first attempt to focus on the electrical treeing rules in both inner and outer insulation layers of high-voltage XLPE power cable. Through statistical experiments and the SEM observation,large difference in treeing character between the inner and outer layers of cable insulation due to the different crystalline status are found. Electrical trees initiating in the inner layer of insulation has shorter initiation time,higher growth rate and greater variety of shapes compared than in the outer layers. The initiation and propagation mechanisms are also discussed.