摘要
实验发现了一种出现在交联聚乙烯电缆绝缘试样中的严重偏离宏观外加电场方向的电树枝单长枝结构,对试样材料的聚集态研究分析表明,这是一种受半结晶聚合物材料聚集态和材料中残存应力影响的在局部高温和高气压作用下的大球晶晶界电树枝。表明厚绝缘高压XLPE电缆绝缘在生产过程中的不均匀结晶和残存应力会对电缆绝缘的电树枝老化性能造成很大影响。
Electrical tree starts and grows along electrical weak region such as impurity, micro-hole, stress and uneven crystalline etc in polymer insulation. It is the main reason that leads main insulation of high voltage plastic cable being break down when running. In our experiment it is found that there is a kind of electrical tree in XLPE cable insulation with a single long branch construction departing from the direction of main tree. Obviously, this is a kind of big crystalline interface tree. The basic reason for this kind of electrical tree branch growth is the congregating state and survival mechanical stress, but the direct driving power is partial high temperature and gas pressure in semi-crystalline polymer. The material around micro-hole be soften by partial high temperature and partial high gas pressure, this is the main developing course of this tree branch. The experiment expresses that there is great influence on electrical tree developing when uneven big crystal or survival mechanical stress exist in thick insulation of high voltage XLPE cable insulation. It means that the insulation production technique is very important for electrical treeing characteristic of high voltage XLPE cable. Due to the very close relationship between the cooling rate, crystalline situation and survival mechanical stress of extrude insulation, we must pay much attention to cooling technic course of XLPE cable insulation。
出处
《电工技术学报》
EI
CSCD
北大核心
2004年第7期44-48,共5页
Transactions of China Electrotechnical Society
关键词
交联聚乙烯
电树枝
聚集态
残存应力
局部高温高气压
XLPE,electrical tree,congregation,survival stress,partial high temperature and gas pressure
