As an interface between the different insulating polymers exists in the joints of High Voltage Direct Current (HVDC) cables, the differences in the field-and-temperature dependence of the conductivities of the materials is regarded as a problem leading to interface charge accumulation and field distortion. In this report, using blocking materials to prevent charge injection from one or both sides of the electrodes, the contributions of charge injection and ionization in low-density polyethylene (LDPE), cross-linked polyethylene with nanoparticles (nano-XLPE) and ethylene propylene diene monomer (EPDM) are distinguished and evaluated based on the results from pulsed electro-acoustic (PEA) method. It is found that the contributions of charge injection and ionization behave differently in different materials. The mechanism behind the field-and-temperature dependences of the conductivities of the three materials is explained successfully. This study helps to clarify the charge transfer mechanism, and thus supports the quantitative calculation of the space charge and electric field distribution in cable joints.

中文翻译：

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高压直流输电电缆接头绝缘材料中运输载体的比较

由于高压直流（HVDC）电缆的接头中存在不同绝缘聚合物之间的界面，因此材料电导率的场-温依赖性的差异被认为是导致界面电荷积聚和场强的问题失真。在此报告中，使用阻挡材料来防止电荷从电极的一侧或两侧注入，这对低密度聚乙烯（LDPE），具有纳米粒子的交联聚乙烯（nano-XLPE）和乙烯丙烯的电荷注入和电离的贡献基于脉冲电声（PEA）方法的结果，对二烯单体（EPDM）进行区分和评估。发现电荷注入和电离的贡献在不同的材料中表现不同。成功地解释了三种材料的电导率与温度和场的关系背后的机理。这项研究有助于阐明电荷转移的机理，从而支持对电缆接头中空间电荷和电场分布的定量计算。