隧道敷设条件下超高压电力电缆热-流场耦合分析

电缆载流量是电力电缆运行中的重要参数。为给敷设于隧道中的超高压电缆运行提供参考，文中根据实际电缆隧道结构和内部电缆排布方式，运用COMSOL Multiphysics仿真软件，建立电缆隧道三维几何模型，进行温度场和流体场的耦合仿真计算。采用有限元法，对不同运行方式和环境条件下的温度场和流体场分布规律进行分析，计算隧道敷设超高压电力电缆载流量。研究表明：最高温度出现在电缆导体处，温度沿着电缆径向逐渐降低，出口截面处的温度和风速相对入口截面处有所增大；随着电流负载增加，电缆发热对周围环境温度的影响也随之增加；双回路和4回路敷设时电缆稳态载流量高于8回路敷设时电缆稳态载流量；电缆表面温度随着通风速率的增加而逐渐减小。

Thermal-fluid coupling analysis of ultra-high voltage cables laid in tunnel

Ampacity is an important parameter in power cable operation. In order to provide a reference for the operation of ultra-high voltage cables laid in tunnel, in this paper, a three-dimensional geometric model is established using COMSOL Multiphysics according to the actual cable tunnel structure and internal cable arrangement to simulate the thermal-fluid coupling. The distribution of temperature and fluid under different operating modes and environmental conditions was analyzed based on finite element method. The ampacity of tunnel ultra-high voltage cables is calculated. It is observed that the highest temperature appears at the conductor, the temperature decreases gradually along the radial direction of cable. Temperature and wind speed at the outlet is increased. With the increase of current, the influence of cable heating on ambient temperature also increases. The steady-state load capacity of cable is higher for double-loop and four-loop laying than for eight-loop laying. Cable surface temperature decreases with increasing ventilation rate.