基于红外测温的电气控制柜内部元件热缺陷严重程度的反问题识别

Inverse Problem Identification of Thermal Defects of Fault Components in Electric Control Cabinet Based on Infrared Temperature Measurement

根据国家相关标准建立了电气控制柜内部元件发热故障的判断方法和标准。结合红外辐射理论分析了控制柜内部过热元件对壳体内表面的热辐射,得到了壳体内表面的辐射热流密度,并针对受热壳体建立了二维热传导模型。基于壳体表面的红外成像测温数据,运用L-M算法进行了导热反问题模拟研究,准确求解了控制柜内部元件在不同热缺陷程度时的发热温度。最后运用表面温度判断法对控制柜内部元件热缺陷的严重程度进行了识别。结果表明,测量误差对过热元件的故障诊断影响较小。

The method and standard for judging overheated components in an electric control cabinet are established according to the related GB in China.The thermal radiation emitted from the overheated components to the inner surface in an electric control cabinet is analyzed according to the infrared radiation theory.The heat flux distribution of the inner surface in the cabinet is obtained and a two-dimensional heat transfer model for the heated cabinet casing is built.On the basis of the infrared imaging temperature measurement data obtained,a L-M algorithm is used to study the inverse heat conduction problem and the heating temperature of the overheated component with different thermal defects in an electric control cabinet is solved accurately.Finally,the severity of the thermal defects of the component in the electric control cabinet is identified by using a surface temperature judgment method.The result shows that the method is useful for the fault diagnosis of the overheated components in electric control cabinets.