【摘要】 搭建输电线路传热特性实验系统,实验测试不同工况下输电线路的传热特性,研究了负载电流,保温层以及大气压力对电缆的表面温度的影响。研究结果表明,热量从电缆内部传递到表面的过程中存在一定热阻,在电缆温度上升过程中,发热量与散热量存在一个逐渐平衡的过程,因此绝缘层表面平均温度高于护套表面平均温度。增大负载电流相当于增加了电缆发热功率,使得电缆的温度时间常数减小而温度上升幅度增大。与未保温的电缆相比,进行保温处理后的电缆散热能力下降,表面温度上升幅度增大,温度时间常数增加。与常压环境相比,低气压环境下空气密度减小,空气冷却效能降低,导致电缆散热效果变差,使得电缆表面温度相对于常压时更高。更多还原

【Abstract】 The heat transfer performance of power cables under different working conditions has been experimentally investigated in this paper. The effect of the load-current, thermal insulating layer and atmospheric pressure on the surface temperature of cable are tested and analyzed. The results show that, there exists a certain thermal resistance in the process of heat transfer from the inside of the cable to the surface, and the amount of heat dissipated gradually matches the amount of heat generated by the cables during the increase of the temperature, therefore the average temperature of the insulation surface is higher than that of the sheath surface. The temperature of cables increases when the load-current rises, while the time constant shows the opposite trend. In addition, compared with the cables without thermal insulation layer, the heat dissipation capability of the cable with insulation is decreased, which results in higher surface temperature and time constant. Moreover, when the atmospheric pressure is decreased, the cooling capacity decreases as the air becomes more rarefied, which results in higher temperature of the cable temperature.更多还原