During the operation of high-voltage cables, external stress and residual stress can affect the aggregated structure of insulating materials and lead to significant deterioration in their electrical performance. To investigate the evolution characteristics of the electrical properties of cross-linked polyethylene (XLPE) under mechanical stress, this paper explains the relationship between the aggregated structure of XLPE and its electrical properties and proposes a method for improving insulation performance under mechanical stress. The results show that metallocene polyethylene used as a nucleating agent can promote crystallisation through heterogeneous nucleation and increase Young's modulus by non-uniform nucleation, increasing crystallinity and reducing interplanar spacing, resulting in more complete crystal forms and reduced damage to the aggregated structure during the tensile process. After nucleating agent modification, the XLPE crystallisation becomes more uniform, and interfacial adhesion forces increase. The weakened interface damage process between the amorphous and crystalline regions under tensile stress effectively inhibits the process of molecular chain polarisation turning and reduces trap density. The modified XLPE crystal structure shows a tendency towards densification and enhanced molecular chain interactions, which can reduce the damage to the aggregated structure under tensile stress, while the reduced free volume inside the material and the shortened average free path of carriers can weaken the damage of high-energy electrons to molecular chains, thereby inhibiting the process of electrical tree degradation. The results show that nucleating agents have great potential for maintaining the stable operation of XLPE cables under mechanical stress.

中文翻译：

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成核剂对拉应力下交联聚乙烯电性能的影响

高压电缆在运行过程中，外应力和残余应力会影响绝缘材料的聚集结构，导致其电气性能显着恶化。为了研究机械应力下交联聚乙烯（XLPE）电性能的演变特征，解释了XLPE的聚集结构与其电性能之间的关系，并提出了一种提高机械应力下绝缘性能的方法。结果表明，茂金属聚乙烯作为成核剂可以通过异相成核促进结晶，并通过非均匀成核提高杨氏模量，提高结晶度并减小晶面间距，从而使晶型更加完整，并减少拉伸过程中对聚集结构的破坏。过程。经过成核剂改性后，XLPE结晶变得更加均匀，界面附着力增加。拉应力作用下非晶区和晶区之间界面损伤过程的减弱，有效抑制了分子​​链极化转向过程，降低了陷阱密度。改性后的XLPE晶体结构呈现致密化趋势，分子链相互作用增强，可以减少拉应力下对聚集结构的破坏，而材料内部自由体积的减少和载流子平均自由程的缩短可以减弱聚集结构的破坏。高能电子到达分子链，从而抑制电树降解过程。结果表明，成核剂对于维持XLPE电缆在机械应力下的稳定运行具有巨大潜力。