电缆终端用硅橡胶的绝缘松弛特性  

Relaxation Characteristics of Silicone Rubber Insulation for Cable Terminations

作　　者：韩圣斌 邓繁盛 李秀峰[1] 李昊泽 马涛 陈钢 Shengbin Han;Fansheng Deng;Xiufeng Li;Haoze Li;Tao Ma;Gang Chen(College of Electric and Electronic Engineering,Shandong University of Technology,Zibo 255000,China;Zibo Power Supply Company,State Grid Shandong Electric Power Company,Zibo 255000,China;Shandong Qixing Electric Technology Development Co.Ltd.,Zibo 255000,China)

机构地区：[1]山东理工大学电气与电子工程学院,山东淄博255000 [2]国网山东省电力公司淄博供电公司,山东淄博255000 [3]山东七星电气科技发展有限公司,山东淄博255000

出　　处：《高分子材料科学与工程》2024年第12期85-96,共12页Polymer Materials Science & Engineering

基　　金：淄博市张店区校城融合发展计划项目(2021JSCG0009)。

摘　　要：硅橡胶的绝缘松弛特性会降低电缆终端界面压力,进而劣化其介电性能,影响电缆的稳定运行。由于松弛特性受交联行为的影响,文中通过调控硫化剂和催化剂的比例,制备了不同交联度的硅橡胶试样,采用多种方法表征了其应力松弛特性,从机械应力和热应力角度对界面压力进行预测。结果表明,温度升高、硅橡胶伸长率增大,会加剧应力松弛,导致界面机械应力减小、压力下降,但分子链段松弛导致热膨胀系数增大,会使热应力增加、界面压力上升。适当提高硅橡胶的交联度,可以增强其耐应力松弛能力。宽频介电谱的研究表明,硅橡胶绝缘存在由分子链松弛极化及偶极链段松弛极化导致的介电松弛过程δ和α,交联度的提高限制了分子链旋转定向及偶极链段的转向运动,使2种介电松弛过程的极化强度降低。高的交联度赋予硅橡胶较强的耐应力松弛能力,预测30年后界面压力保持率可高达90.7%,且具有较长的储存周期。研究结果可为硅橡胶绝缘电缆附件的运行状态和寿命评估提供参考。The relaxation characteristics of silicone rubber insulation will reduce the terminal interface pressure of cable,and then deteriorate its dielectric properties,affecting the stable operation of cable.Since the relaxation characteristics are affected by crosslinking behavior,silicone rubber samples with different crosslinking degrees were prepared by adjusting the proportion of vulcanizing agent and catalyst,the stress relaxation characteristics were characterized by various methods,and the interface pressure was predicted from the perspective of mechanical stress and thermal stress.The results show that with the increase of temperature and elongation of silicone rubber,the stress relaxation will be intensified,resulting in the decrease of interfacial mechanical stress and pressure,but the relaxation of molecular chain segments will lead to the increase of thermal expansion coefficient,resulting in increase of thermal stress and interfacial pressure.Properly increasing the crosslinking degree of silicone rubber can enhance its stress relaxation resistance.The study of broadband dielectric spectroscopy shows that there are dielectric relaxation processesδandαcaused by the molecular chain relaxation polarization and dipole chain relaxation polarization of silicone rubber insulation.The increase of crosslinking degree limits the rotational orientation of molecular chains and steering motion of dipole chain segments,and decreases the polarization intensity of the two dielectric relaxation processes.High crosslinking degree gives silicone rubber strong stress relaxation resistance,and it is predicted that the interfacial pressure retention rate can be as high as 90.7%after 30 years,and showing a long storage period.The results can provide reference for the evaluation of the running state and life of silicone rubber insulated cable accessories.

关 键 词：硅橡胶 交联度 分子链运动 应力松弛特性 介电松弛性能 

分 类 号：TM247[一般工业技术—材料科学与工程]