不同敷设方式下±500 kV高压直流海缆稳态载流量仿真分析

Simulation Analysis of Steady-state Ampacity of ±500 kV High-voltage DC Submarine Cables Under Different Laying Methods

稳态载流量是衡量高压直流海缆电能传输能力的重要指标。为此,采用COMSOL Multiphysics有限元分析软件建立了±500kV直流海缆电-热-流耦合模型,基于控制变量法研究了J型管、电缆沟和隧道3种典型敷设方式下的尺寸参数、材料热导率、排列方式等对海缆稳态载流量的影响。结果表明:在J型管敷设段,减小J型管管壁厚度和增大J型管外径均可有效提高海缆稳态载流量;在电缆沟敷设段,随着埋深的增加,稳态载流量逐渐降低,而空气域截面尺寸和电缆沟材料热导率的增大则可提高稳态载流量;在隧道敷设段,考虑到空气对流换热等因素,当电缆横向排列且间距为900mm时,稳态载流量达到最大值;稳态载流量最低的隧道段为瓶颈段,可通过增加通风设备提升瓶颈段稳态载流量。

The steady-state ampacity is an important index to measure the power transmission capacity of high-voltage DC submarine cables. In this paper, an electric-thermal-flow coupling model of ±500 kV DC submarine cables was built by using the COMSOL Multiphysics finite-element analysis software. Based on the control variate method, the effects of dimensional parameters, material thermal conductivity and arrangement on the steady-state ampacity of the submarine cables were studied, which were laid in 3 different sections, including the J-tube section, the cable trench section and the tunnel section. The results show that, in the J-tube section, the steady-state ampacity can be increased by both reducing the wall thickness and increasing the outer diameter of the J-tube. In the cable trench section, the steady-state ampacity gradually decreases with the increase of the depth of the cable trench. However, it can be effectively boosted by increasing the cross-section size of the air domain in the cable trench and increasing the thermal conductivity of the cable trench materials. In the tunnel section, due to the factors such as air convection and heat transfer, the steady-state ampacity reaches its maximum when the submarine cables are arranged horizontally with a space of 900 mm. The tunnel section with the lowest steady-state ampacity is the bottleneck section, which can be improved by adding ventilation equipment.