Nanocomposites have been proven to be an important dielectric material, which provides advanced dielectric properties of insulation to power equipment. For the use of polyethylene (PE)-based nanocomposites in HVDC cable insulation, their temperature dependence needs to be considered, because it could deeply affect the conductivity and space charge behavior. To investigate the temperature dependence of conductivity and space charge properties of the cross-linked polyethylene (XLPE)/graphene oxide (GO) nanocomposites, XLPE samples with GO mass fractions of 0, 0.001, 0.01 and 0.1 wt% were prepared. The conductivity, space charge behavior and breakdown strength of the nanocomposites were tested. Then, the surface potential decay (SPD) was measured to elucidate the mechanism of the GO nanoparticles in the XLPE matrix according to the trap theory. The obtained experimental results showed that the XLPE/GO nanocomposites with the mass fraction of 0.01 wt% exhibited a lower conductivity, lower space charge accumulation, and higher DC breakdown strength than those of the neat XLPE. This observation is related to the nanoparticle-polymer interaction regions and the deep traps introduced by the GO nanoparticles. In addition, the temperature dependence of the electrical properties of nanocomposites decreased when appropriate GO amounts were added. This result indicates that the XLPE/GO nanocomposites are more suitable for use in HVDC cable insulation.

中文翻译：

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用于高压直流电缆绝缘的 XLPE/GO 纳米复合材料的温度相关直流电导率和空间电荷分布

纳米复合材料已被证明是一种重要的介电材料，可为电力设备提供先进的绝缘介电性能。对于在高压直流电缆绝缘中使用聚乙烯 (PE) 基纳米复合材料，需要考虑它们的温度依赖性，因为它会严重影响电导率和空间电荷行为。为了研究交联聚乙烯 (XLPE)/氧化石墨烯 (GO) 纳米复合材料的电导率和空间电荷特性的温度依赖性，制备了 GO 质量分数为 0、0.001、0.01 和 0.1 wt% 的 XLPE 样品。测试了纳米复合材料的导电性、空间电荷行为和击穿强度。然后，根据陷阱理论测量表面电位衰减（SPD）以阐明 GO 纳米粒子在 XLPE 基质中的机制。获得的实验结果表明，质量分数为 0.01 wt% 的 XLPE/GO 纳米复合材料比纯 XLPE 具有更低的电导率、更低的空间电荷积累和更高的直流击穿强度。这一观察结果与纳米颗粒-聚合物相互作用区域和 GO 纳米颗粒引入的深陷阱有关。此外，当添加适量的 GO 时，纳米复合材料的电性能的温度依赖性降低。该结果表明 XLPE/GO 纳米复合材料更适合用于高压直流电缆绝缘。这一观察结果与纳米颗粒-聚合物相互作用区域和 GO 纳米颗粒引入的深陷阱有关。此外，当添加适量的 GO 时，纳米复合材料的电性能的温度依赖性降低。该结果表明 XLPE/GO 纳米复合材料更适合用于高压直流电缆绝缘。这一观察结果与纳米颗粒-聚合物相互作用区域和 GO 纳米颗粒引入的深陷阱有关。此外，当添加适量的 GO 时，纳米复合材料的电性能的温度依赖性降低。该结果表明 XLPE/GO 纳米复合材料更适合用于高压直流电缆绝缘。