输电导线截面不均匀温度场的有限元模拟

FEM Simulation on Heterogeneous Temperature Field of Transmission Lines

为了分析输电导线不均匀温度场,提出了一种基于有限元计算动态下输电导线截面上不均匀温度场的数值方法,可以考虑瞬态条件下导线的热传导、太阳辐射、空气对流、强制对流等环境条件因素的影响。该方法突破了传统的摩尔根公式的局限性,获得了动态变化外界环境条件下输电导线的暂态温度场响应,得到导线截面上不均匀温度场分布。在此基础上,详细地分析了不均匀温度分布和外部环境条件之间的内在联系。结果表明:传统的摩尔根公式所预测结果在大载流量、大表面吸热系数(旧线)、高环境温度以及高太阳辐照条件下存在较大误差,在这些条件下必须考虑导线截面的温度不均匀分布。此外,传统摩尔根公式预测温度低于有限元模拟所得导线截面上的最高温度,基于它的设计偏于危险,在以上条件下其应用应该谨慎或做相应的修正处理。

In order to analyze the heterogeneous temperature field of transmission lines,numerical simulation basing on the finite element method(FEM)was performed to capture the heterogeneous temperature field of transmission lines under transient condition.The effects of external environmental conditions such as heat conduction,solar radiation,air convection and forced convection on the temperature field were discussed carefully in the present paper.By using the FEM simulations,the heterogeneous temperature field on the section of the conductor was captured.In addition,the transient temperature response of the transmission lines was also obtained for the dynamic environmental condition.Further,the relationship between the heterogeneous temperature field and the parameters of external environment conditions has been analyzed in detail.The results show that when the ampacity,the surface coefficient,the ambient temperature and the solar radiation are high enough,the temperature estimated by Morgan method is lower than the highest temperature of the section.Obviously,the present FEM simulations can break through the limitation of classical Morgan method,and the application of classical Morgan formula should be carefully under the above conditions.