Electrical Tree Growth and Partial Discharge in Epoxy Resin Under Combined AC and DC Voltage Waveforms
Electrical Tree Growth and Partial Discharge in Epoxy Resin Under Combined AC and DC Voltage Waveforms
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DOI：
10.1109/tdei.2018.007310
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发表时间：
2018-12-01
影响因子：
3.1
通讯作者：
Schurch, Roger
中科院分区：
文献类型：
--
作者：
Iddrissu, Ibrahim;Rowland, Simon M.;Schurch, Roger
采用交流、正直流偏置和负直流偏置三种波形，研究了直流偏压对环氧树脂(Araldite LY(R)5052/Aradur(R)HY 5052)电树生长和局部放电(PD)特性的影响。使用的是针面样本。结果表明，在直流和50赫兹交流的共同作用下，树木的生长速度超过了交流的生长速度。正直流偏置测试和负直流偏置测试分别导致平均故障时间减少62%和54%。不同的树形结构和发育阶段与不同的局部放电特性有关，粗大的深色树枝与较高的局部放电幅度有关，而细树通道的生长与局部放电幅度小于1pC有关。交流测试显示了树木生长的五个不同阶段，而直流偏置测试则显示了四个阶段。特别是，在交流测试的后期阶段观察到的从平面到点电极的反向生长的树在直流偏置测试中看不到。结果表明，在复合电压下，交流分量是树木生长的主要驱动力，而直流分量可以促进树木的生长。因此，交流噪声可能会危及高压直流网络中绝缘的可靠性。
The effect of DC bias on electrical tree growth and partial discharge (PD) characteristics in epoxy resin (Araldite LY (R) 5052/Aradur (R) HY 5052 supplied by Huntsman) is investigated using three waveforms: AC, AC with positive DC bias, and AC with negative DC bias. Needle-plane samples are used. Tree growth is shown to be accelerated by the combined effect of DC and 50 Hz AC, beyond the AC growth rate. Positive and negative DC biased tests result in 62% and 54% reductions in average time to breakdown, respectively. Different tree structures and stages of development are associated with different partial discharge characteristics, with thick dark tree branches associated with high PD magnitudes, whereas fine tree channel growth is linked with PD magnitudes below 1 pC. AC tests showed five distinct stages of tree growth compared to four stages seen in DC biased tests. In particular, trees growing in the 'reverse direction' from the planar to the point electrode, which is observed in the latter stages of AC tests, is not seen in the DC biased tests. It is concluded that for composite voltages, the AC component is the essential driver of tree growth but the DC component can accelerate propagation. AC noise may therefore compromise the reliability of insulation in HVDC networks.