基于电磁热多场耦合的直埋电缆导体温度与载流量计算

Calculation of Conductor Temperature and Ampacity of Directly Buried Cable Based on Electromagnetic Thermal Multi Field Coupling

为研究地下电缆导体温度和载流量以及设计合理的电缆敷设方式,结合传热学理论、利用有限元分析法,建立了埋在地下电力电缆的电磁热耦合计算模型,基于该模型载流量的计算结果与基于IEC 60287标准的计算结果进行对比验证。探讨了电缆敷设深度、相间距离、热回填及相序的变化对电力电缆导体温度和载流量的影响,通过多元线性回归分析了不同因素对电缆导体温度及载流量影响的强弱程度。研究结果表明,电缆的敷设方式较大地影响着电缆导体温度及载流量:敷设深度越大,相间距离越小,热回填导热系数越小,电缆导体温度越高,载流量越低;其中,热回填导热系数对电缆导体温度及载流量的影响最为显著,相序影响最小。因此在直埋电缆敷设工程中,应配合高导热系数的热回填,增强电缆散热效果,从而保障电缆安全经济运行。

In order to study the temperature and current carrying capacity of underground cable conductors and design reasonable cable laying methods,combined with the knowledge of heat transfer and using finite element analysis,a calculation model of electromagnetic thermal coupling for buried power cables is established,and the current carrying capacity of the model is calculated.The calculation result is compared and verified with the calculation result based on the IEC 60287 standard.The influence of cable laying depth,interphase distance,thermal backfill and phase sequence changes on the temperature and current carrying capacity of power cable conductors is discussed,and the degree of influence of different factors on the temperature and current carrying capacity of cable conductors is analyzed through multiple linear regression.The research results show that the cable laying method greatly affects the cable conductor temperature and ampacity.The greater the laying depth,the smaller the interphase distance,the smaller the thermal conductivity of the thermal backfill,the higher the cable conductor temperature,the lower the ampacity.The thermal conductivity of backfill has the most significant effect on the temperature and ampacity of the cable conductor,and the phase sequence has the smallest effect.Therefore,in the direct buried cable laying project,thermal backfill with high thermal conductivity should be used to enhance the heat dissipation effect of the cable,thereby ensuring the safe and economic operation of the cable.