电缆高分子绝缘层整体热老化下红外测温热物性的定量评估

Thermal Properties Quantitive Evaluation of Overall Thermal Aging Cable Insulation Using Infrared Inspection Technique

电缆高分子绝缘材料因受高温等因素的影响容易发生老化,及时评估其老化状况有利于预防事故发生。文中采用共轭梯度反问题技术结合红外检测手段,对整体热老化后的绝缘材料导热率进行了定量评估。通过电缆热特征分析发现,电缆表面温度并不能真实反映绝缘层的整体热老化状况,而缆芯温度和接线端温度随着绝缘层老化的加剧而升高。文中通过不同红外测温误差和初始假设的数值实验对提出的热物性定量评估方法进行了验证,表明了其定量评估结果的可靠性及稳定性。

The insulation of cable ages easily due to high temperature and other factors. Therefore, it is important to evaluate the ageing process of insulation quantitatively to prevent accident. In this paper, the conductiviy of overall thermal aging insulation is quantitatively evaluated by the conjugate gradient method along with the infrared thermography. Through the analysis of thermal characteristic of cable, it is found that the cable surface temperatures do not response to the overall thermal aging, while temperatures of the cable core and terminal increase with the overall thermal aging of insulation. The reliability and stability of the quantitative evaluation method introduced here are verified by the numerical experiments considering the influence of temperature measurement errors and initial assumptions.