中文摘要：

交联聚乙烯（cross-linked polyethylene,XLPE）电缆绝缘热老化产生的气体可能会在电树枝发生处产生局部高气压,为了研究不同运行状况下局部气压对XLPE电缆电树枝引发和生长特性的影响,以XLPE电缆制作绝缘层切块为试验样品搭建了试验系统,研究了不同温度下局部气压作用在电树枝通道时的局部放电特性和电树枝的生长规律。结果表明：XLPE处于玻璃态时,局部气压对电树枝的引发无明显作用,在生长过程中通道内流注的发展因高气压受阻,树枝发展被抑制;XLPE处于高弹态时,气隙放电的产生导致电树枝引发时间大大缩短。在生长发展期,高温造成XLPE结构上的缺陷促进了高气压下局放的发展。试验发现：高温高气压下电树枝很容易贯穿电缆绝缘,严重威胁XLPE电缆的安全稳定运行。

英文摘要：

Thermal aging of cross-linked polyethylene（XLPE） cable may generate gases where electrical trees occur. In order to study the influence of partial air pressure on initiation and the propagation of electrical trees in XLPE cable in different operation conditions, a test system has been set up which use XLPE material sections as test samples. The experiment was conducted to investigate the propagation regularity and the partial discharge features of the electrical tree on partial air pressure at different temperatures, which is acted on the channels of the tree. The results show that when XLPE is in glassy state, partial air pressure has no significant influence on the initiation of electrical trees. In the growth process, the development of radial streamer discharges has been suppressed by air pressure. When XLPE is in elastomeric state, the generation of gap discharge lead to the initiation time of electrical trees is obviously reduced. And during the growth and development period, structural defects caused by high temperatures accelerate the partial discharge under high air pressure. It is found by test results in this paper that the electrical trees are easily breakthrough the cable insulation under high temperature and high air pressure, it is a serious threat to security and stability of XLPE cables.