近年来，随着现代城市快速发展，配网电缆的建设与运维越来越受到重视。10 kV 交联聚乙烯电缆是城市配网电缆中的最常见的一种，在很多城市的配网电缆线 路中已占据超过九成。冷缩中间接头因其性能优越，在电缆线路中运用非常广泛， 使得冷缩中间接头故障已超过电缆故障的半成。由于接头中的复合绝缘界面存在 电场畸变和应力集中的现象，当界面绝缘强度不足时会发生界面击穿故障，故界面 击穿是一种常见的接头故障形式。冷缩接头通过冷缩管的硅橡胶绝缘与电缆本体 的交联聚乙烯绝缘进行过盈配合，产生适当的界面压强，以保证界面具有足够的电 气强度，因此有必要对该界面绝缘强度的影响因素展开研究。本文主要通过两个直接影响复合界面绝缘强度的因素:界面压强和硅脂涂覆 展开研究，同时硅脂、温度、绝缘尺寸又能通过影响硅橡胶的力学性能来改变界面 压强，因此将界面压强作为重点研究对象。首先，通过弹性力学的方法分析了交联聚乙烯电缆冷缩接头的应力分布，得到 了界面压强的计算式。利用调研的实际产品尺寸，通过 ANSYS 软件建立仿真模型， 将仿真结果与理论计算结果进行比较，并考察了高温和两个尺寸参数对界面压强 的影响。再使用薄膜压力传感器，对常温和高温下的界面压强进行实际测量，进一 步验证理论计算结果。然后，通过加速老化试验研究了硅橡胶的应力松弛现象，分析热老化单独作用 及热-机械老化协同作用下硅橡胶的应力松弛特性，并在热-机械协同老化下对比有 无硅脂时硅橡胶应力松弛特性的区别。通过时温等效原理得到电缆工作温度下的 长期应力松弛特性，与对应的接头界面压强长期变化曲线，讨论了扩张率、硅脂涂 覆和温度对界面压强带来的影响。最后，通过界面交流击穿试验，分析了界面压强和硅脂两个因素对界面电气强 度的直接影响。

In recent years, with the rapid development of modern cities, more attention haven been drawn to the construction and maintenance of distribution network cables. The cross-linked polyethylene(XLPE) cable at 10 kV, a common voltage level in urban distribution networks, composes over 90% of the distribution network cables in many cities. Due to the XLPE-SR interface and electric field stress concentration caused by the structure of the joint, more than half of all the cable failures originate in joints, which usually begin with the breakdown of the interface. The silicone rubber(SR) insulation of the cold-shrink joint and the XLPE insulation of the cable form an interface pressure through an interference fit to ensure sufficient electrical strength, so it is necessary to study the influencing factors affecting the electrical strength of the interface.Interfacial pressure and silicone grease are considered as two direct factors affecting the electrical strength of the composite interface, while temperature and silicone grease are seen as indirect factors that change the interface pressure by affecting the mechanical properties of silicone rubber. Therefore, the interface pressure is deemed to be a key study object as it is a direct factor that can be influenced by indirect factors.Firstly, the stress distribution of the cold-shrink joint is analyzed by elastic mechanics and the calculation formula of the interfacial pressure is obtained. With the actual product measurement figures, a simulation model is established by ANSYS software in both normal temperature and higher operating temperature to simulate the interfacial pressure. The influence of two size parameters on the interfacial pressure is discussed. A thin-film pressure sensor is used at normal temperature and high temperature to further verify the theoretical calculation results.Then, through the accelerated aging test, the stress relaxation phenomenon of silicone rubber is studied to explore the effect of thermal aging and thermo-mechanical aging on the mechanical properties of silicone rubber, and the test result with or without silicone grease under thermo-mechanical synergistic aging is compared. The long-term stress relaxation characteristics of silicone rubber and the long-term variation of interfacial pressure under operating temperature are obtained by the time-temperature equivalent principle. The effects of expansion rate, silicone grease and temperature are discussed.Finally, the influences of interface pressure and silicone grease on the electrical strength of the interface are discussed through the interface breakdown test.