高压直流海底电缆三维仿真模型简化等效研究

Study on Simplification and Equivalence of 3D Simulation Model of HVDC Submarine Cables

温度分布和载流量是反映海底电缆运行状态的重要参数。依据南澳直流工程±160 kV高压直流海底电缆,利用COMSOL Multiphysics有限元分析软件,建立了电缆的三维(three-dimensional,3D)仿真模型,提出了电缆暂态模型的简化方法。在整个厚度不变的基础上,将多个薄层与邻接介质作为3个等效层,采用调和平均法计算等效层的导热系数,利用IEC 60287标准计算等效层的比热容和密度,解决了电缆薄层网格剖分过密的问题。通过对比研究仿真模型简化前后不同载流量下的电缆温度分布,验证了简化方法的正确性和有效性。

Temperature distribution and ampacity are two important parameters to reflect the operating state of submarine cables. According to the ± 160 kV HVDC submarine cable of Nan＇ao project, a three-dimensional （3D） simulation model of the cable is set up and a simplification method of cable transient model is proposed by using COMSOL Multiphysics finite element analysis software. On the basis of the constant thickness, multiple thin layers and adjacent medium are used as three equivalent layers. The thermal conductivity of the equivalent layer is computed by harmonic mean method, and the specific heat capacity and density of the equivalent layer are calculated by IEC 60287 method, which solve the problem that the meshs in the thin layer of the cable are too dense. Through the simulation model, the temperature distribution of cables under different ampacity is compared before and after simplification, which verifies the correctness and effectiveness of the simplification method.