土壤热湿传递下的直埋电缆载流量数值计算

Numerical calculation of direct buried power cable ampacity with soil heat-moisture transfer

中文关键词: 直埋电缆  热湿耦合  载流量  正交计算  数值模拟

英文关键词: direct buried power cable  coupling of heat and moisture  ampacity  orthogonal calculation  numerical simulation

中文摘要:

      针对土壤热湿过程对直埋电缆载流量的影响，修正土壤热湿耦合模型，联合MAXWELL方程组，建立电磁-热湿三场耦合模型。利用三场耦合模型和COMSOL Multiphysics软件按正交法计算不同敷设土壤类型、干密度和粒径下的YJV22 0.6/1 3×6直埋电缆载流量。通过对比正交计算结果的最大、最小载流量组的磁通密度、发热量、温度分布、含水率分布等，发现大载流量组的缆芯发热量较高，但电缆外表皮温度较低，使得直埋电缆内部热流密度较大，同时电缆周围土壤的导热系数和含水率较高，发生的湿分运移和相变较为微弱，使得缆芯的热量及时被导出。土壤中的湿分运移和相变对于直埋电缆的载流量有一定提升作用。

英文摘要:

      The effect of heat and moisture transfer in soil on the ampacity of direct buried power cables was studied. An electromagnetic-heat-moisture three-field coupling model was established with the modified soil heat-moisture coupling model and the MAXWELL equation. The three-field coupling model and the COMSOL Multiphysics software was used to calculate the YJV22 0.6/1 3×6 ampacity of direct buried power cable under different soil types, dry density and particle size by orthogonal method. The magnetic flux density, heat generation, temperature distribution, and moisture content distribution were compared between the cases of maximum and minimum ampacity. Results shows the heat generation of the highest ampacity case is higher, but the temperature of the cable outer surface is lower, which makes the heat flux higher. Meanwhile, the thermal conductivity and moisture content of the soil around the cable is higher in the maximum ampacity case, and the moisture transfer and the phase change are weak. The moisture transfer and phase change in the soil can improve the ampacity of the direct buried power cable.