高频电压下交联聚乙烯电缆绝缘中电树枝生长的动力学模型

Dynamics model for electrical tree propagation in cross-linked polyethylene cable insulation under high frequency voltage

针对高压交联聚乙烯电缆绝缘试样,在1000—2000Hz10kV峰值正弦电压下,采用计算机实时显微数字摄像技术进行了电树枝培养实验.基于半结晶绝缘材料中电树枝生长机理和电树枝结构的分形特征,提出了一个在高频范围定量预测电应力驱动下交联聚乙烯电缆绝缘中电树枝生长特性的动力学模型,获得了电树枝生长率方程和从电树枝生长到击穿过程的寿命公式.将该模型预测值与实验中获得的电树枝生长规律实验数据进行比较,其结果有较好的一致性,表明提出的模型化方法可以应用到交联聚乙烯电缆绝缘中电树枝老化规律的定量分析研究中.

In this paper we investigated the structures and propagation characteristics of electrical trees observed in the high volatage cross-linked polyethylene （XLPE） cable insulation samples under high volatage of 10kV at frequency of 1000—2000Hz. Based on the specific tree growth mechanism and the fractal nature of tree structures, a dynamic model has been developed to qualitatively predict the electrical tree growth characteristics in XLPE cable insulation when subjected to an electrical stress under high frequency voltage, and then the tree growth rate equation and life formula of tree growth to breakdown are derived.We performed electrical tree growth tests in XLPE cable insulation samples at high frequency and compared the results, which showed that the proposed model was in good agreement with the expreriment.So,it seems that the proposeed model can be applied to the qualitative analysis of aging law of electrical tree in XLPE cable insulation.