油浸式变压器内外辐射传热的数值分析

Numerical Analysis of Internal and External Radiation Heat Transfer in Oil⁃immersed Transformer

热点温度是衡量油浸式变压器绝缘性能和安全裕度的重要指标,对其进行快速和准确地计算具有重要的意义。文中研究了油浸式变压器的内外辐射传热机理,依据辐射传递方程(RTE)和斯蒂芬—波尔茨曼方程建立了辐射传热数值计算模型。以一台110 kV油浸式变压器为例,通过有限元仿真对其内外辐射传热过程进行了数值分析。结果显示,忽略内辐射过程引起的绕组热点温度误差小于2%,并且能够提升33%的计算效率。外辐射换热系数与对流换热系数处于同一数量级,对绕组热点温度影响达到16%,在数值计算中不可被忽略。

Hot spot temperature is an important index to measure the insulation performance and safety margin of oil⁃immersed transformer,and it is of great significance to calculate it quickly and accurately.In this paper,the internal and external radiation heat transfer mechanism of oil⁃immersed transformer is studied.A numerical calculation mod⁃el of radiation heat transfer is set up based on the radiation transfer equation(RTE)and Stephen⁃Boltzmann Equation.A set of 110 kV oil⁃immersed transformer is taken as an example,the numerical analysis of its internal and external radiation heat transfer process is performed through finite element simulation.The results show that the temperature error of the winding hot spot caused by ignoring the internal radiation process is less than 2%,and the calculation effi⁃ciency can be improved by 33%.The external radiation heat transfer coefficient is in the same order of magnitude as the convective heat transfer coefficient.The effect of external radiation heat transfer on the hot spot temperature of the winding reaches up to 16%,which cannot be ignored in the numerical calculation.