电缆绝缘层老化对接头界面压力的影响研究

The influence of aging cable insulation on the interface pressure of cable joint

为研究老化电缆绝缘层弹性模量变化对界面压力的影响,文中实测3根不同运行年限电缆绝缘的击穿场强与介质损耗角正切表征其电性能,不同温度下的弹性模量表征其力学性能。基于超弹性材料本构理论,计算电缆接头与本体装配后的界面压力,并建立电缆接头的二维轴向仿真模型,计算轴向上的界面压力。仿真结果与理论计算结果的对比表明,运用二维轴向仿真模型计算电缆接头与本体之间的界面压力的误差不超过3.2%,仿真模型计算的准确度可为研究接头轴向上的界面压力分布提供可靠数据,虽然不同运行年限电缆绝缘层电性能不同,且弹性模量最大差异为29%,但界面压力仅变化0.275%。因此,全新接头与已运行一定年限的电缆装配后,仍能保证足够的界面压力。

To study the influence of the change in elastic modulus of retried cable insulation on interface pressure,the breakdown field strength and dielectric loss angle tangent of cable insulation with different operating years are measured to characterize the electrical properties,as well as the mechanical properties of the elastic modulus at different temperatures. Based on the constitutive theory of hyperelastic materials,the interface pressure of new cable joint assembled on the cable is calculated. Meanwhile,a two-dimensional axial simulation model of the cable joints is established,and the axial distribution of interface pressure is analyzed. The comparisons between simulation and theoretical results show that the error of the interface pressure between the cable body and the joint is not more than 3.2% by using the two-dimensional axial simulation model. The accuracy of the simulation model can provide reliable data for studying the interface pressure distribution on the joint axis maximum. Although the electrical performance of the insulation layer of the cable of different operating years is different,and the difference of cable insulation elastic modulus with different operation year is 29%,but the interface pressure changes only by0.275%. Therefore,when the new cable joint assembled on the old cable,the interface pressure is sufficient enough.