为了消除瓷绝缘子裂纹对设备稳定运行的威胁, 提出了基于红外热波检测的裂纹缺陷成像增强方法。然而, 瓷绝缘子表面的低发射率限制了红外热波的检测效果。针对这一问题,从后处理算法和表面涂覆涂层两个方面对缺陷成像效果进行增强。对未涂覆室温硫化(room temperature vulcanized,RTV)硅橡胶涂层的瓷绝缘子的表面裂纹进行分析, 发现表面釉层会在瓷绝缘子伞裙边缘产生“高温”区域,导致裂纹缺陷的成像效果不理想。采用一阶微分处理后的特征成像能消除了非缺陷异常温度区域的影响, 增强裂纹缺陷的成像效果。对涂覆 RTV 硅橡胶涂层的瓷绝缘子表面裂纹缺陷开展检测发现, 涂覆RTV硅橡胶涂层提高了表面发射率, 消除了加性噪声,裂纹缺陷的成像效果得到了显著增强。研究表明, 结合一阶微分与特征成像的后处理方法,能够显著提升红外热波检测瓷绝缘子裂纹缺陷的成像效果。此外, 瓷绝缘子表面若涂覆RTV硅橡胶涂层, 也能增强缺陷成像显示。
英文摘要:
To eliminate the threat posed by cracks in porcelain insulators to the stable operation of equipment, an enhanced imaging method for crack defect detection based on active infrared thermography is proposed. However, the low emissivity of porcelain insulator surfaces limits the effectiveness of active infrared thermography. To address this issue, this paper enhances defect imaging from two aspects: post-processing algorithms and surface coating treatments. For porcelain insulators without room temperature vulcanized (RTV) silicone rubber coating, analysis of surface cracks reveals that the surface glaze creates "hot spots" at the edges of the insulator skirts, resulting in suboptimal imaging of crack defects. By applying first-order differential processing, the characteristic imaging effectively eliminates the influence of non-defect anomalous temperature regions, thereby improving the imaging quality of crack defects. For porcelain insulators coated with RTV silicone rubber coating, the RTV silicone rubber coating increases surface emissivity and suppresses additive noise, significantly enhancing crack defect imaging. The results demonstrate that combining first-order differentiation and characteristic imaging in post-processing can markedly improve the imaging of crack defects in porcelain insulators using active infrared thermography. Furthermore, applying an RTV silicone rubber coating to the porcelain insulator surface further enhances defect visualization.