10 kV电缆熔融接头运行状态下的电-热-力耦合仿真分析

Electrical-thermal-mechanical coupling simulation analysis of 10 kV cable fusion joint under operation

电缆熔融接头相较于传统电缆接头无需应力锥、无活动界面的优点在新电缆投运项目以及旧电缆改造维修项目中更有前景,为了对熔融接头在电网运行中的性能进行评估,通过对熔融接头在电网运行下的电-热-力耦合仿真,改变熔融接头、运行电流有效值、考虑短时过载以及绝缘层的材料参数等,研究电缆接头的应力分布和温度分布。结果表明:当电缆熔融接头新、旧绝缘层的材料参数差异增大时会使旧绝缘层与新绝缘层的界面处应力分布不均匀;运行电流有效值的增加则既会提高熔融接头整体温度,又会提高绝缘层应力;短时过载运行1 h的径向应力约为稳态运行时的4倍,轴向应力约为稳态运行时的3倍,线芯温度高出约80 K。

Compared with the traditional cable joint, the cable fusion joint has the advantages of no stress cone and no movable interface, which has more promising in the new cable operation project and the old cable reconstruction and maintenance project. In order to evaluate the performance of fusion joint after long-term operation in the power grid, the fusion joint was conducted electro-thermal-mechanical coupling simulation under the operation of power grid. The stress distribution and temperature distribution of cable joint were studied through changing the effective value of operating current and considering the short-time overload and material parameter difference between new and old insulation layer. The simulation results show that the stress distribution at the interface between the old and new insulation layer is uneven when the material parameter difference between the new and old insulation layer increases. The increase of operating current will not only increase the overall temperature of fusion joint, but also increase the stress of insulating layer. The radial stress of short-time overload operation for 1 hour is about 4 times bigger than that of steady-state operation, the axial stress is about 3times bigger than that of steady-state operation, and the core temperature is about 80 K higher.