Wei Yanhui, Liu Mingyue, Wang Jiaxing, Li Guochang, Hao Chuncheng, Lei Qingquan
Institute of Advanced Electrical Materials, Qingdao University of Science and Technology, Qingdao 266042, China.
Polymers (Basel). 2019 Aug 5;11(8):1309. doi: 10.3390/polym11081309.
For high voltage direct current (HVDC) cable, a semi-conductive layer lies between the conductor and the insulation layer; as the charge migrates the path from the conductor to the insulation material, it will affect space charge injection. In this work, the research idea of changing the injection path of moving charges within semi-conductive layer by magnetic particles was proposed. Semi-conductive composites with different SrFeO contents of 1 wt.%, 5 wt.%, 10 wt.%, 20 wt.%, and 30 wt.% were prepared, and the amount of injected charges in the insulation sample was characterized by space charge distribution, polarization current, and thermally-stimulated depolarization current. The experimental results show that a small amount of SrFeO can significantly reduce charge injection in the insulation sample, owing to the deflection of the charge migration path, and only part of the electrons can enter the insulation sample. When the content is 5 wt.%, the insulation sample has the smallest charge amount, 0.89 × 10 C, decreasing by 37%, and the steady-state current is 6.01 × 10 A, decreasing by 22%. When SrFeO content exceeds 10 wt.%, the charge suppression effect is not obvious and even leads to the increase of charge amount in the insulation sample, owing to the secondary injection of charges. Most moving charges will deflect towards the horizontal direction and cannot direct access to the insulation sample, resulting in a large number of charges accumulation in the semi-conductive layer. These charges will seriously enhance the interface electric field near the insulation sample, leading to the secondary injection of charges, which are easier to inject into the insulation sample.
对于高压直流（HVDC）电缆，在导体和绝缘层之间存在一个半导电层；当电荷从导体迁移到绝缘材料的路径上时，会影响空间电荷注入。在这项工作中，提出了通过磁性颗粒改变半导电层内移动电荷注入路径的研究思路。制备了不同SrFeO含量（1 wt.%、5 wt.%、10 wt.%、20 wt.%和30 wt.%）的半导电复合材料，并通过空间电荷分布、极化电流和热刺激去极化电流来表征绝缘样品中的注入电荷量。实验结果表明，少量的SrFeO由于电荷迁移路径的偏转，能显著减少绝缘样品中的电荷注入，只有部分电子能进入绝缘样品。当含量为5 wt.%时，绝缘样品的电荷量最小，为0.89×10 C，减少了37%，稳态电流为6.01×10 A，减少了22%。当SrFeO含量超过10 wt.%时，电荷抑制效果不明显，甚至由于电荷的二次注入导致绝缘样品中的电荷量增加。大多数移动电荷会向水平方向偏转，无法直接进入绝缘样品，导致大量电荷在半导电层中积累。这些电荷会严重增强绝缘样品附近的界面电场，导致电荷的二次注入，使其更容易注入绝缘样品。
