中文摘要：

为了研究局部气压对交联聚乙烯（XLPE）电缆电树枝引发和生长的影响，分别以XLPE电缆制作插针缺陷和XLPE绝缘层切块为试验样品搭建了试验系统，研究了局部气压作用在电缆绝缘层内壁和电树枝通道内时的局部放电特征和电树枝的生长规律。结果表明：气压作用在绝缘层内壁对电树枝的引发和初期的生长没有明显影响，在生长后期对电树枝的生长速度有促进作用，树枝分形维数减小，扩展系数增大；气压作用在电树枝通道内会导致放电模式转变为流注放电，放电脉冲几乎分布在整个相位上。分析表明绝缘层内壁高气压导致大面积高温软化区产生形变是促进电树枝生长的主要因素；树枝通道内高气压使气体密度增加导致碰撞电离加剧是流注放电发生时间提前的原因。

英文摘要：

In order to study the initiation and growth of electrical trees in XLPE cable influenced by local air pressure, using samples of XLPE cable with artificial defect made with needle and square-cut XLPE slices as examples, we built up a test system to investigate the growth regularity and partial discharge features of the electrical trees in the inner insulation layers or the channels of the trees with local air pressure on. The results show that the air pressure acting on the inner in- sulation layers has no significant influence on the initiation and early growth of electrical tree, but in the later growth stage, it promotes the trees＇ growth rate, decreases the trees＇ dimension and increases the trees＇ expanding coefficient. On the other hand, the pressure acting on the channels of a tree alters the discharge pattern into streamer discharge while the discharge pulses distribute nearly in all phases. Further analysis indicates that the deformation of softening area at high temperatures under the air pressure is the main factor that promotes the electrical tree growth, and the increased gas den- sity which causes more violent collision ionization will primarily cause the earlier streamer discharge.