交联聚乙烯中的滞长型丛林状电树枝特性研究

为了弄清楚电树枝生长机理以利于研究耐电树高聚物材料，采用实时显微数字摄像监测技术监测交联聚乙烯中电树枝引发与生长过程。结果发现，在低频下电树枝长成丛枝状后不再生长。原因是绝缘体中被注入分布均匀的空间电荷，构成电场屏蔽，使电树枝尖端处的电场强度降至介质的击穿场强以下，使树枝停止生长。而局部放电、树枝尖端微击穿和电极向介质中注入电荷这三种作用同时加速电树枝的迅速生长。

Study on the characteristics of electrical tree with bush structure and growing very slowly in low frequency

Because the close relationship between initiation and growth of electrical tree and partial discharge in channel of the tree, there is direct proportion relationship between degree of discharge and frequency of applying voltages. so, there must be a direct proportion relationship between branch numbers and voltage frequency, this has been proved by our experiments. But it is found also that above experimental result is just a general course, because a few electrical tree become bush like in very long growing period. The mechanism is discussed in this paper.