【作者】 李俊；

【导师】 李立浧； 黄嘉盛；

【作者基本信息】 华南理工大学 ， 电气工程（专业学位）， 2023， 硕士

【摘要】 随着城市用电负荷密度日益增大,城市配网电力输送需求高速增长但输电通道资源愈发紧张的现状,集群化敷设方式在配网电缆线路中的使用越发广泛。配网电缆线路主要分为排管集群敷设电缆和电缆沟集群敷设电缆,对其进行准确热评估是提高配网输电线路可靠性和利用率的关键。同时,在负荷密度较高区域的集群化敷设电缆易出现过载运行现象,电缆线路长期过热运行最终可能会引发火灾、爆炸等电力事故。因此,针对配网电缆线路热的负荷能力提升措施研究亟待关注。针对现有解析计算模型在计算配网集群敷设电缆温度场精度不足以及配网电缆线路热的负荷能力提升的问题,本文展开配网排管集群敷设电缆及电缆沟敷设电缆的热评估计算和负荷能力提升措施研究,具体研究内容如下:1)研究了单根排管敷设电缆的散热特性,并提出了管道内无填充介质及有填充介质情况下单根排管敷设电缆导体温度的计算方法。随后,针对IEC方法在计算排管集群敷设电缆温度场时计算精度不足的问题,提出了考虑电缆间互热影响的排管集群敷设电缆热评估优化模型,实现对不同负荷电流下排管敷设集群电缆的导体温度计算。最后,通过搭建10k V 3×120mm~2的排管敷设电缆大电流温升实验平台验证了本文所提出的排管集群敷设电缆热评估优化模型的准确性。2)针对传统IEC模型在计算配网电缆沟内相互接触排列电缆导体温度时精度不足的问题,基于配网电缆沟内电缆的对流散热特性和辐射散热特性提出了电缆沟内相互接触排列电缆的热评估优化模型,并通过有限元仿真模型分析了IEC方法在计算电缆沟内相互接触排列电缆导体温度时的误差。随后,通过搭建20k V 3×35mm~2的电缆沟敷设电缆大电流温升实验平台验证了本文所提出的电缆沟敷设电缆热评估优化模型的准确性。3)搭建了基于实验条件的排管敷设电缆和电缆沟敷设电缆的电磁-热-流多物理场耦合仿真模型。随后,基于排管敷设电缆的有限元仿真模型,研究了不同导热系数的管内填充材料、不同管道材质和不同导热系数的水泥预制件与排管敷设电缆载流量的关系。最后,基于电缆沟敷设电缆的有限元仿真模型,研究了不同导热系数的沟内填充材料和不同排列方式与电缆沟敷设电缆载流量的关系。更多还原

【Abstract】 With the increasing density of urban power load,the power transmission demand of urban distribution network is growing rapidly,but the transmission channel resources are becoming increasingly tight,so the clustering laying mode is more and more widely used in the distribution network cable lines.Distribution network cable lines are mainly divided into row laying cables and trench laying cables.Accurate thermal evaluation is the key to improve the reliability and utilization rate of lines.Especially in areas with high load density,long-term overheated operation of cable lines may eventually lead to fire,explosion and other power accidents.Therefore,it is urgent to pay attention to the research on load capacity improvement measures of distribution network cable line heat.In view of the insufficient accuracy of the existing analytical calculation model in calculating the temperature field of the cables laid in the distribution network cluster and the improvement of the thermal load capacity of the cable lines in the distribution network,this paper carries out the research on the thermal evaluation calculation and load capacity improvement measures of the cables laid in the distribution network cluster and the cables laid in the cable trench.The specific research contents are as follows:1)The heat dissipation characteristics of single row laying cable are studied,and the calculation method of conductor temperature of single row laying cable with no or no filling medium in the pipeline is proposed.Then,in view of the insufficient calculation accuracy of IEC method in calculating the cable of trunking cluster,a thermal evaluation optimization model of trunking cluster cable considering the influence of mutual heat between cables was proposed to calculate the conductor temperature of trunking cluster cable under different load distribution conditions.Finally,the accuracy of the proposed thermal evaluation optimization model for trunked cable was verified by setting up a 10k V 3×120mm~2 high-current temperature rise experimental platform.2)Aiming at the low accuracy of the traditional IEC model in calculating the temperature of the cable conductors in the contact arrangement in the distribution network cable trench,based on the convection heat dissipation characteristics and radiation heat dissipation characteristics of the cables in the distribution network cable trench,a thermal evaluation and optimization model of the cables in the contact arrangement in the cable trench is proposed.The error of IEC method in calculating the conductor temperature of cable trench contact arrangement is verified by finite element simulation model.Then,through constructing 20k V3×35mm~2 was in cable trench cable laying large current temperature rise experiment platform is put forward by this paper is verified in cable trench laying cable heat to assess the accuracy of the optimization model.3)Based on the experimental conditions,the electromagnetic,thermal and flow multi-physical field coupling simulation model of row laying cable and cable trench laying cable is built.Then,based on the finite element simulation model of the tubular laying cable,the relationship between the filling medium with different thermal conductivity,different pipe materials and cement prefabricated parts with different thermal conductivity and the carrying capacity of the tubular laying cable was studied.Finally,based on the finite element simulation model of cable laying,the relationship between the filling medium with different thermal conductivity and different arrangement modes and the carrying capacity of cable laying was studied.更多还原