500 kV电力电缆稳态热路模型分析及载流量计算

Analysis of Steady-state Heat Path Model and Calculation of Current Carrying Capacity for 500 kV Power Cable

通过对交流500 kV XLPE电力电缆各层材料进行导热系数测量实验,测得电缆各层材料导热系数随温度的变化曲线及电缆稳态工作温度下各层材料的热阻系数,并对电缆各层材料的热阻进行归并处理,然后按IEC 60287-1-1:2006对敷设于隧道中的交流500 kV电力电缆建立稳态热路模型并进行分析。结果表明:利用稳态热路模型可计算分析电缆各层热阻、外界环境热阻、电缆损耗及电缆温升等,同时得到大截面、五分裂的交流500 kV电力电缆在最高允许工作温度(90℃)下的载流量I为2 543 A。通过温升实验表明,电缆载流量的理论计算值与实验值的误差可控制在5%以内,验证了该模型对电缆载流量预测的准确性。

The thermal conductivity of each layer materials in AC 500 kV XLPE power cable were measured,and the change curves of thermal conductivity with temperature and the thermal resistance coefficient of each layer materials under the steady-state operating temperature of cable were obtained.Then the thermal resistance of each layer materials were merged,and a steady-state heat path model of AC500 kV power cable laid in tunnel was established according to IEC 60287-1-1:2006 and then analyzed.The results show that the thermal resistance of each layers in cable,external environment thermal resistance,cable loss,and cable temperature rise can be calculated by the steady-state heat path model,and the current carrying capacity(I)of the AC 500 kV power cable with large cross-section and five-split conductor is 2 543 A under the highest allowable working temperature(90℃).The temperature rise experiment indicates that the error between the theoretical value and experimental value of current carrying capacity for cable can be controlled within 5%,which verify the accuracy of the model for predicting the current carrying capacity of cable.