In this article, a detection method based on microwave technique is proposed to detect the internal defects of composite insulators. Based on this method, an automatic detection system is developed for full-size composite insulator. In the experiments with 110-kV composite insulators, three types of defects, namely the air-gap defect, carbonization defect, and conductive defect, are artificially made, and they are located exactly by the developed automatic defect detection system. It is found that, due to the dielectric constant and magnetic permeability properties, the conductive defect can be detected easily, whereas the carbonization defect is the most difficult one to be detected among all three defects. In addition, a real defective 500-kV composite insulator from transmission line after years of operation is also detected by the developed system and the results are consistent with the infrared imaging method. According to the test results, the developed system is efficient, labor-saving, and robust. It can have a great potential in the quality control of composite insulators.

中文翻译：

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基于微波技术的全尺寸复合绝缘子内部缺陷检测

本文提出了一种基于微波技术的复合绝缘子内部缺陷检测方法。基于该方法，研制了全尺寸复合绝缘子自动检测系统。在110kV复合绝缘子实验中，人工制造了气隙缺陷、碳化缺陷和导电缺陷三类缺陷，并通过开发的缺陷自动检测系统准确定位。发现由于介电常数和磁导率特性，导电缺陷很容易检测，而碳化缺陷是所有三种缺陷中最难检测的一种。此外，研制的系统还对运行多年的输电线路实际有缺陷的500 kV复合绝缘子进行了检测，结果与红外成像方法一致。根据测试结果，所开发的系统高效、省力、健壮。它在复合绝缘子的质量控制方面具有很大的潜力。