In this study, three kinds of inorganic fillers are chosen and filled into ethylene-propylene-diene monomer (EPDM) matrix, including silicon carbide, copper calcium titanate (CCTO), and vanadium dioxide (VO₂). The electrical properties of the three modified composites at different temperatures have been systematically studied. The intrinsic conductance behaviours of different inorganic fillers on the direct current conductance and electric breakdown strength of the composite dielectrics are also analysed, and the possible mechanism for non-linear conductivity is revealed. The electrical conductivity increases with the increase of fillers content, where 30 wt.% CCTO/EPDM composite dielectric has a high non-linear coefficient of 5.71. The increase in temperature can further increase the conductivity of the composites, accompanying a lower breakdown strength. When the temperature rises to 70°C, the VO₂/EPDM composite has a higher conductivity, but the electric breakdown strength degrades seriously. The simulation results show that the composites with non-linear electrical conductivity characteristics can effectively uniform the electric field and solve the problem of electric field concentration at the root of the stress cone, which is beneficial to improving the safe operation of the cable accessories.

中文翻译：

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通过调节无机填料实现乙烯-丙烯-二烯单体基复合电介质的非线性电导率

在这项研究中，选择了三种无机填料填充到三元乙丙橡胶（EPDM）基体中，包括碳化硅、钛酸铜钙（CCTO）和二氧化钒（VO 2 ）_。）。对三种改性复合材料在不同温度下的电性能进行了系统研究。还分析了不同无机填料的本征电导行为对复合电介质的直流电导和击穿强度的影响，并揭示了非线性电导率的可能机制。电导率随着填料含量的增加而增加，其中30 wt.%的CCTO/EPDM复合电介质具有高达5.71的非线性系数。温度的升高可以进一步提高复合材料的电导率，同时降低击穿强度。当温度升至70°C时，VO ₂/EPDM复合材料具有较高的导电率，但电击穿强度严重下降。仿真结果表明，具有非线性导电特性的复合材料能够有效均匀电场，解决应力锥根部电场集中问题，有利于提高电缆附件的安全运行。