基于有限元法的电缆金属护套感应电压仿真分析

Simulation Analysis of Induced Voltage on Metal Sheath of Power Cable Based on Finite Element Method

为有效降低单芯电缆金属护套感应电压对电缆寿命及载流量的影响,科学合理地选择不同电缆结构的敷设排列方式和距离,利用有限元法对不同材料、结构的电缆金属护套感应电压进行了数值仿真分析。首先采用电磁感应定律对单芯电缆金属护套感应电压进行解析计算;再通过Ansoft Maxwell 15软件建立单回路电缆金属护套感应电压的3维简化模型,并验证了有限元分析方法的适用范围。在此基础上,计算护套、半导电屏蔽层在不同相对磁导率、体积电导率条件下的感应电压值,分析了钢带铠装层对金属护套感应电压的影响。结果表明,当金属护套的体积电导率由105 S/m增大到107 S/m时,电缆金属护套感应电压约降低2.86%;而当屏蔽材料的体积电导率由104 S/m增大到105 S/m时,电缆金属护套感应电压约降低6.06%。当金属护套的相对磁导率由1增大到10时,电缆金属护套感应电压约升高48.48%;而当屏蔽材料的相对磁导率由1增大到10时,电缆金属护套感应电压约升高6.06%;与无铠装层电缆相比,装有金属铠装层电缆的金属护套感应电压增大了近100%。

In order to decrease the influence of induced voltage at metal sheath of single-core cable on the cable＇s lifetime and current-carrying capacity, and to select reasonable laying arrangement and distance for different cable structures, we numerically simulated and analyzed the induced voltage on metal sheath of various materials and structures. Firstly, we calculated the induced voltage on metal sheath of single-core cable using the analytic formulas based on electromagnetic induction law. Then, we established a 3-D model of metal sheath of single-core cable using Ansoft Maxwell 15, and vali- dated the applicability of this finite element model. Meanwhile, we calculated the induced voltage of metal sheath and semiconduction shielding layer with different relative magnetic permeability and bulk conductivity, and then we analyzed the effect of steel armour coating on the induced voltage. The results show that, when the bulk conductivity of metal sheath increases from 10^5 S/m to 10^7 S/m, the induced voltage on metal sheath decreases by about 2.86%, but when the bulk conductivity of shield material increases from 10^4 S/m to 10^5 S/m, the induced voltage decreases by about 6.06%. Moreover, the induced voltage increases by about 48.48% when the relative magnetic permeability increases from 1 to 10 in metal sheath, and by about 6.06% for the similar increase in shield material. Compared with cable in the absence of metal amour, the induced voltage of cable in the presence of armour coat almost doubles.