Yin Hongxia, Cui Yingcao, Wei Yanhui, Hao Chuncheng, Lei Qingquan
Advanced Institute of Electrical Materials, Qingdao University of Science and Technology, Qingdao 266042, China.
State Key Laboratory of Advanced Power Transmission Technology Global Energy Interconnection Research Institute co., Ltd., Beijing 102209, China.
Polymers (Basel). 2020 Apr 4;12(4):809. doi: 10.3390/polym12040809.
The semi-conductive layer located between the wire core and the insulation layer in high voltage direct current (HVDC) cable plays a vital role in uniform electric field and affecting space charges behaviors. In this work, the research idea of adding ionic conductive particles to semi-conductive materials to improve the conductive network and reduce the energy of the moving charge inside it and to suppress charge injection was proposed. Semi-conductive composites doped with different LaSrMnO (LSM) contents were prepared. Resistivity at different temperatures was measured to investigate the positive temperature coefficient (PTC) effect. Pulse electro-acoustic (PEA) method and thermal-stimulation depolarization currents (TSDC) tests of the insulation layers were carried out. From the results, space charge distribution and TSDC currents in the insulation samples were analyzed to evaluate the inhibitory effect on space charge injection. When LSM content is 6 wt. %, the experimental results show that the PTC effect of the specimen and charge injection are both being suppressed significantly. The maximum resistivity of it is decreased by 53.3% and the insulation sample has the smallest charge amount, 1.85 × 10 C under 10 kV/mm-decreased by 40%, 3.6 × 10 C under 20 kV/mm-decreased by 45%, and 6.42 × 10 C under 30 kV/mm-decreased by 26%. When the LSM content reaches 10 wt. %, the suppression effect on the PTC effect and the charge injection are both weakened, owing to the agglomeration of the conductive particles inside the composites which leads to the interface electric field distortion and results in charge injection enhancement.
高压直流（HVDC）电缆中位于线芯与绝缘层之间的半导电层在均匀电场以及影响空间电荷行为方面起着至关重要的作用。在这项工作中，提出了向半导电材料中添加离子导电颗粒以改善导电网络、降低其内部移动电荷的能量并抑制电荷注入的研究思路。制备了掺杂不同含量LaSrMnO（LSM）的半导电复合材料。测量不同温度下的电阻率以研究正温度系数（PTC）效应。对绝缘层进行了脉冲电声（PEA）法和热刺激去极化电流（TSDC）测试。根据结果，分析了绝缘样品中的空间电荷分布和TSDC电流，以评估对空间电荷注入的抑制效果。当LSM含量为6 wt.%时，实验结果表明试样的PTC效应和电荷注入均得到显著抑制。其最大电阻率降低了53.3%，绝缘样品的电荷量最小，在10 kV/mm下为1.85×10 C，降低了40%；在20 kV/mm下为3.6×10 C，降低了45%；在30 kV/mm下为6.42×10 C，降低了26%。当LSM含量达到10 wt.%时，由于复合材料内部导电颗粒的团聚导致界面电场畸变并致使电荷注入增强，对PTC效应和电荷注入的抑制作用均减弱。
