The influence of AC and DC voltages on electrical treeing in low density polyethylene
The influence of AC and DC voltages on electrical treeing in low density polyethylene
复制标题
交直流电压对低密度聚乙烯电树的影响
DOI：
10.1016/j.ijepes.2019.105386
复制
发表时间：
2020
影响因子：
5.2
通讯作者：
S. Rowland
中科院分区：
文献类型：
--
作者：
Hualong Zheng;George Chen;S. Rowland
电树生长是一个众所周知的过程，它会导致高压聚合物绝缘在交流应力下失效。然而，树枝生长在高压直流输电绝缘失效中的作用还不是很清楚。这项工作考虑了交直流复合电压作用下聚合物绝缘中的电树退化问题。在LDPE针面几何结构的样品中进行的测试产生了三种类型的电树，它们的生长取决于交流分量的大小，而与直流电压无关。在交流分量为10 千伏(峰值)的试验中，12 千伏和15 千伏的树分别以树状通道的导电性和树形区分，分别被称为导电树、非导电树枝或非导电灌木树。在交流电压为10 的情况下，叠加−20 的直流电压可显著加速树枝的萌发。在+20 的直流电压下，接枝的树有更多的分叉，但对树的起始时间没有太大的影响。低密度聚乙烯薄膜上的空间电荷测量为理解+DC电压和−DC电压下树枝萌生的差异提供了基础。偏置10 千伏交流电压不影响导电树的后续繁殖。在12 和15 的交流电压下，正偏压对不导电树枝和灌木的生长均有促进作用。−15 kVDC对灌木生长有一定的抑制作用。直流电压极性对树体形态的影响对于树枝和灌木是不同的。树枝和灌木的PD大小与树木生长的关系也不同。树长决定了树枝的PD幅值，灌木树的PD幅值的演化表明，附加的直流应力对PD幅值没有影响。然而，通过对灌木树的局部放电分析，已经证实了直流偏置对正负放电对称性的影响。此外，灌木树形状的改变被认为与PD不对称性的变化有关。这项工作说明了交流波纹在高压直流绝缘失效机制中的重要性。
Electrical tree growth is a well-documented process leading to failure of high voltage polymeric insulation under AC stresses. However, tree growth in HVDC insulation failure is not well understood. This work considers electrical tree degradation in polymeric insulation subjected to combined AC and DC voltages. Tests in LDPE samples of needle-plane geometry yield three types of electrical trees, which grow depending on the magnitude of the AC components, irrespective of the DC voltages. In tests with an AC component of 10 kV (peak amplitude), 12 kV and 15 kV trees are distinguished by both the conductivity of tree channels and the tree shape, and are referred to as either conducting trees, non-conducting branch trees or non-conducting bush trees respectively. With 10 kV AC, tree initiation was significantly accelerated by superimposing −20 kV DC. With +20 kV DC, the incepted trees had more bifurcations, but there was no major change to tree initiation time. Space charge measurements on thin LDPE films provide a basis for understanding the difference between tree initiation with +DC and −DC voltages. The subsequent propagation of conducting trees were not influenced by biasing the 10 kV AC. With 12 kV AC and 15 kV AC, the growths of non-conducting branch and bush trees were both accelerated by positive biasing. A retardation was observed in bush tree growth with −15 kV DC. The effects of DC voltage polarity on tree morphology are different for branch and bush trees. Different relationships between PD magnitudes and tree growth were also found between branch and bush trees. The tree length determined PD magnitudes in branch trees and the evolution of PD in bush trees suggest that the additional DC stress has no impact to PD magnitudes. Nevertheless, DC bias effects on the symmetry between positive and negative discharges have been evidenced through PD analysis for bush trees. Moreover, the modifications on the shape of bush trees are believed to be associated with the changes in PD asymmetry. This work has illustrated the importance of AC ripples in the failure mechanisms in HVDC insulation.
DOI：
10.1109/tdei.2017.006544
发表时间：
2017-06-01
影响因子：
3.1
作者：
Iddrissu, Ibrahim;Zheng, Hualong;Rowland, Simon M.
通讯作者：
Rowland, Simon M.
DOI：
10.1109/tdei.2018.007310
发表时间：
2018-12-01
影响因子：
3.1
作者：
Iddrissu, Ibrahim;Rowland, Simon M.;Schurch, Roger
通讯作者：
Schurch, Roger