This paper focuses on the space charge and electric field characteristics in the extrusion molded joint (EMJ) for ±500 kV HVDC submarine cables. The double-layered XLPE samples are prepared to imitate the insulation interface in the EMJ, and the space charge characteristics are assessed utilizing the pulsed electro-acoustic (PEA) method. Then, a two-dimensional simulation model for space charge based on a modified BCT model containing the ionic charges is established. The results demonstrate that the simulation outcomes based on the modified BCT model exhibit consistency with the experimental observations by measuring the mobilities and trap characteristics of electrons and holes. The results of full-sized EMJ simulation present that the negative space charges mainly accumulate near the interface, resulting in the distortion of the field in the cable insulation. Meanwhile, the interface charges diminish the electric field value at the interface but intensify the angle and tangential component of the interface field. The electric field distortion is mitigated when the crosslinking temperature for the reinforcing insulation is adjusted to 180 °C. The simulation method of space charge and electric field in the EMJ insulation based on the modified BCT model can provide research means for the design and manufacture of the EMJ for HVDC submarine cables.

中文翻译：

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HVDC 海底电缆 XLPE 绝缘挤压成型接头的空间电荷和电场特性：实验与模拟


本文重点研究±500 kV HVDC 海底电缆挤压成型接头（EMJ）中的空间电荷和电场特性。制备双层 XLPE 样品来模拟 EMJ 中的绝缘界面，并利用脉冲电声 (PEA) 方法评估空间电荷特性。然后，基于改进的包含离子电荷的BCT模型，建立了空间电荷的二维模拟模型。结果表明，基于改进的BCT模型的模拟结果与通过测量电子和空穴的迁移率和陷阱特性得到的实验观察结果一致。全尺寸EMJ模拟结果表明，负空间电荷主要在界面附近聚集，导致电缆绝缘中的场发生畸变。同时，界面电荷减小了界面处的电场值，但增强了界面场的角度和切向分量。当增强绝缘的交联温度调整至 180 °C 时，电场畸变得到缓解。基于改进BCT模型的EMJ绝缘内空间电荷和电场仿真方法可为高压直流海缆EMJ的设计和制造提供研究手段。