The mode of laying power cable in pipes was designed to allow additional cable circuits to meet the future load increase.For different positions of original and additional cables,the temperature field and ampacity are different.It is,therefore,necessary to optimize the positions of original cables and additional ones.A finite element model is built in this paper by taking the 3 ×4 pipes for laying distribution cables as an example,and the validity of the model is verified by comparing the results of temperature-rise experiments and that of simulation.Based on the model,the positions of the original 6-circuit and 1 additional circuit are optimized based on the lowest conductor temperature of the most serious heating cable under the condition of same ampactiy for all circuits.The simulation result shows that the more scattered the cables are,the more uniform the temperature field is,and the lower the conductor temperature of the most serious heating cable.The optimal position of the additional cable is related to the position of original cables.Therefore,it is suggested that the future additional cables should be taking into account when optimizing the original position of cables.%电缆排管敷设设计之初就考虑到了通过增加电缆回路满足后期增容要求.3缆原始及新增位置不同时,断面温度场和载流量也不同,故有必要对电缆原始及新增位置进行优化.以3x4排管敷设配电电缆为例,建立温度场有限元模型,对比温升试验与有限元计算结果,验证r有限元模型的有效性;基于该模型,在各回路加载相同电流前提下,以发热最严重电缆线芯温度最低为依据,对原始6网路及新增1回路进行位置优化.仿真研究表明,电缆分布越分散温度场分布越均匀,发热最严重电缆线芯温度越低;最优新增电缆位置与原电缆位置有关,因而建议在电缆位置优化时应考虑后期电缆回路的增加.
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