变压器绝缘纸热阻特性的理论分析与实验研究

Theoretical analysis and experimental research on thermal resistance characteristics of transformer insulating paper

利用双热流计法设计实验,在同一温度下对不同厚度绝缘纸的热阻进行测量,得到关于单位面积热阻与厚度的关系,通过对实验数据的分析实现接触热阻和体热阻的分离,以求得该温度下绝缘纸的导热系数和接触热阻。由AFM表面微观形貌图对每个热流通道的接触分热阻建立锥截体模型,并选用Hertz弹性模型描述接触表面的弹性形变,再利用高斯分布求得表面凸起的接触概率,即可求得表面接触热阻的大小,实验结果表明,绝缘纸的平均导热系数为0. 069 8W/(m·K),绝缘纸与紫铜间面积接触热阻为0. 002 67m^2K/W,接触热阻的数值计算值为0. 002 45 m^2K/W。绝缘纸与紫铜间面积接触热阻的实验值与数值分析结果的相对偏差为8. 98%。

Using double heat flow meter method design experiment,measuring thermal resistance of different thickness insulating paper at the same temperature,the relationship between the thermal resistance and the thickness of the insulating material per unit area was obtained.Realize the separation of thermal contact resistance and thermal body resistance through the analysis of experimental data,so as to obtain the thermal conductivity and thermal contact resistance of the insulating paper at this temperature.The frustum model is established for each heat channel using AFM micro surface map,and use Hertz model to describe the elastic deformation of the contact surface,the contact probability distribution obtained by Gauss surface distribution,then solve the surface thermal contact resistance′s value.The experimental results show that the average thermal conductivity of insulating paper is 0.069 8W/(m·K),and the thermal contact resistance between insulating paper and copper is 0.002 67m 2K/W,and the numerical value of contact resistance is 0.002 45 m 2K/W.The relative deviation between the experimental value and the calculated value is 8.98%.