形态对聚乙烯中空间电荷包运动特性的影响

Effects of Morphology on Movement of Space Charge Packet in Polyethylene

空间电荷相关研究是直流电介质材料特性研究的重要领域,聚乙烯则是主要的内绝缘材料之一。为了对高压直流条件下聚乙烯中的空间电荷现象进行深入研究,应用电声脉冲法空间电荷测量系统对高场强下低密度聚乙烯中的空间电荷现象进行测量,观察到了空间电荷包现象。研究结合不同热处理方法得到了不同微观形态的聚乙烯试品,并在不同场强下结合微观形态的变化对低密度聚乙烯的空间电荷包运动速率进行了分析。结果表明,聚乙烯的微观形态对空间电荷包特性有显著的影响,也对空间电荷包运动速率有明显的影响,结晶度越高,空间电荷包运动速率越小。

Polyethylene is a major kind of internal insulating material. This paper measured the space charge phenomenon in low-density polyethylene （LDPE） by the pulsed electro-acoustic （PEA） method and observed the space charge packet. This research got the LDPE films of different morphology by different annealing rate and discussed the effect of morphology and electrical field stress changing on space charge packer＇s moving velocity. The research shows that morphology of LDPE affects the velocity of space charge packet remarkably; bigger crystallinity results in lower velocity of space charge packet. The intensity of electrical field has little affection to the velocity. The average mobility of different crystallinity under different electric field was calculated. The relationship between crystallinity and mobility was found. The results further demonstrate there are inherent relationships among higher crystallinity, more space charge accumulation, lower mobility and deeper trap depth. Lower mobility and deeper trap depth have a monotone relationship.