非线性应力管电缆终端的电—热场分析

Electric-thermal Field Analysis for Cable Terminals Equipped with Nonlinear Stress Control Tubes

笔者基于变分原理,推导了非线性的时域有限元电场计算方程和稳态热场有限元方程,分别利用商用软件Integrated Engineering Software和有温度分布解析解的轴对称电缆结构验证了编制程序的正确性,并利用该方法分析了含线性、非线性以及复合结构的应力管时的电缆终端电场和热场分布。分析结果表明,线性、非线性以及复合结构的应力管,通过适当的选择其结构和材料的参数都能很好的均匀终端的场强分布,但含非线性应力管的电缆终端的损耗和温升远小于含线性以及复合结构应力管的电缆终端,这为冷缩式电缆终端设计提供了一个指导方向。

In order to fully understand the consequences of the interaction of electric and thermal fields,a time-domain finite element（FE） equation and an FE equation were derived for describing such electric and thermal fields based on the variational principle.Two comprehensive finite element calculation codes were compiled for electric field and thermal field,respectively.The validity of the FE code for time-domain electric field was verified by comparing the simulation results with the predictions of a commercial package,named integrated engineering software（IES）.The thermal FE code was validated by analytical solution of temperature distribution in a coaxial cable.A comparison of the electric field and thermal field distributions in cable terminals equipped with linear,nonlinear,or composite structural stress control tubes（SCT） was presented.The results reveal that a uniform electric field distribution is achievable by selecting appropriate structure and material for cable terminals,and significant reduction in terminal loss and temperature elevation is found in cable terminals by employing nonlinear SCT.And it is of great practical significance for cold-shrinkable terminal design.