基于红外测温的电气控制柜内部元件热缺陷温度与方位的三维反问题识别

Three-dimensional inverse problem identification of thermal defect temperature and the position of fault components in the electrical control cabinet based on infrared temperature measurement

结合红外辐射理论分别建立了控制柜内部单个和多个元件过热时对壳体内表面的红外辐射模型,得到了壳体内表面总的热流密度分布,并针对受热壳体建立三维热传导模型。基于对壳体表面红外成像测温,运用共轭梯度法进行了导热反问题模拟研究,对控制柜内部元件的发热温度和方位同时进行了识别,最后分析了测量误差对计算结果的影响。得出结论:对单个故障元件的发热温度和方位同时进行反演求解,得到了精确的计算结果;对两个故障元件的发热温度和方位分开求解时,取得了较高的求解精度;对两个故障元件的发热温度和方位同时进行反演求解,也能获得准确的计算结果。测量误差较小时,对过热元件的故障诊断影响较小,故障元件的发热温度受测量误差影响更大。

Thermal radiation model of the inner surface of the casing resulting from overheating of single and multiple fault components in the control cabinet was established respectively according to the infrared radiation theory. Total heat flux distribution of the inner surface of the casing was obtained. A three- dimensional heat transfer model was built against the heated casing. An inverse heat conduction problem was studied based on the infrared imaging temperature measurement on the surface of the casing according to the conjugate gradient method. The overheating temperature and position of the fault components in the control cabinet were identified. Finally, the effects of measurement errors on computational results were analyzed. The results show that the overheating temperature and position of single fault component can be solved accurately, the conjugate gradient method is also very suitable tocalculate the overheating temperature and the position of two fault components together. measurement error is small, the identified results are little affected, and the effect of measurement errors on the identification of overheating temperature is more than that of the fault components When the temperature position of