Propagation of electrical tree structures in solid polymeric insulation
Propagation of electrical tree structures in solid polymeric insulation
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DOI：
10.1109/94.598282
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发表时间：
1997-06-01
影响因子：
3.1
通讯作者：
Alison, JM
中科院分区：
文献类型：
--
作者：
Dissado, LA;Dodd, SJ;Alison, JM
存在两种可供选择的理论方法来研究电树繁殖。随机模型将树结构归因于随机概率因素，而在放电-雪崩模型中，机制驱动的场波动是负责任的。在这里，我们根据现有的实验证据回顾了这些方法的预测。结果表明，两种模型都给出了实验观察到的分形结构和结构分布形式，但预测的分布函数的宽度小于实验发现的分布函数。物理模型可用的定量公式还使其能够再现树繁殖的其他一些特征，如电压依赖性、生长规律和放电行为模式。这在没有机械假设的随机方法中是不可能的，因为机械假设很难与随机过程联系起来。探讨了放电-雪崩模型与确定性混沌之间的联系。实验证据支持电树现象是确定性击穿机制在低于失控击穿所需场强的混沌状态下运行的结果。提出空间电荷沉积和重排是混沌场波动的物理根源。根据放电-雪崩模型的预测，树木的形状与树木生长过程中可用波动范围的变化有关。
Two alternative theoretical approaches to electrical tree propagation exist. Stochastic models attribute tree structures to random probabilistic factors, whereas in the discharge-avalanche model mechanism-driven field fluctuations are responsible. Here we review the predictions of these approaches in the light of the available experimental evidence. It is shown that both models give the fractal structures and the form of structure distribution observed experimentally The width of the distribution functions predicted are, however, less than those found experimentally The quantitative formulation available to the physical model also enables it to reproduce several other features of tree propagation such as voltage dependence, growth laws, and discharge behavior patterns. This is not possible in the stochastic approach without mechanistic assumptions which are difficult to relate to the stochastic process. The connection between the discharge-avalanche model and deterministic chaos is explored. Experimental evidence is presented supporting the contention that the electrical treeing phenomenon is the result of a deterministic breakdown mechanism operating in a chaotic regime at fields lower than those required for runaway breakdown. Space-charge deposition and re-arrangement is proposed as the physical origin of the chaotic field fluctuations. Tree shapes are shown to be related to the variation in the fluctuation range available as the tree grows in accord with the predictions of the discharge-avalanche model.