环氧复合绝缘内部缺陷超声自动检测系统

Ultrasonic Automatic Detection System for InternalDefects of Epoxy Composite Insulation

环氧复合绝缘子密度不均匀和内部集中缺陷严重威胁着气体绝缘金属封闭开关设备(gas insulated metal-enclosed switchgear, GIS)的安全运行,目前超声检测方法存在缺陷检测不直观、效率低等问题。针对此,基于超声反射原理研制环氧复合绝缘材料内部缺陷超声自动成像系统。首先采用小波分析对非重复性超声回波信号进行降噪;然后对回波波形的相邻波峰时间差、电压峰值和电压相邻波峰间的零信号时间进行特征融合识别,得到试样缺陷的位置-超声特征数据集;最后实现环氧复合绝缘缺陷超声自动成像。分别用本文检测系统和传统检测方式对密度不均匀和不同深度、取向裂纹的环氧复合绝缘试样进行检测和对比分析。结果表明:该系统与质量体积法测量的局部密度误差小于4.8%;内部集中性缺陷检测结果和缺陷原貌具有一致性;检测效率较传统人工超声检测提升近6倍。该系统实现了环氧复合绝缘材料的内部集中缺陷和密度不均匀检测的统一,在绝缘子出厂试验和故障分析缺陷定位方面较传统人工检测方式在检测效率和直观性上具有一定优势。

The safe operation of gas-insulated metal-enclosed switchgear(GIS)is seriously threatened by density non-uniformity and concentrated internal defects of epoxy composite insulators.There are deficiencies in the ultrasonic detection methods,such as non-intuitive defect detection and low efficiency.Therefore,this study develops an ultrasonic automatic imaging system for internal defects of epoxy composite insulator materials based on the principle of ultrasonic reflection.Firstly,it uses wavelet analysis to denoise non-repetitive ultrasound echo signals.Then,feature fusion recognition is performed on the time differences between adjacent peaks of the echo waveform,voltage peak,and zero signal time between adjacent voltage peaks to obtain the sample defect location-ultrasonic feature dataset.Finally,the automatic ultrasonic imaging of epoxy composite insulation defects is realized.The study uses the developed system and the traditional detection methods respectively to detect and compare the epoxy composite insulation samples with density non-uniformity and cracks of different depths and orientations.The results show that the local density error between the system and the mass volume method is less than 4.8%.The detection results of internal concentrated defects are consistent with the original appearance of defects,and the detection efficiency of the system is nearly 6 times higher than that of the traditional artificial ultrasonic detection.This detection system combines the detection of concentrated internal defects and density non-uniformity in insulation materials.Compared with the traditional manual detection methods,it offers significant advantages in terms of detection efficiency and intuitiveness in insulator delivery testing and defect localization after faults.