电力绝缘子层间气隙太赫兹检测与定量分析

THz Detection and Quantitative Analysis of Interlayer Air Gap in Power Insulators

电力绝缘子具有机械强度高、表面不易发生裂缝、老化速度慢等功能,在电力领域具有广泛应用。为了研究电力绝缘子层间气隙,构建了具有三层电力绝缘子的太赫兹(THz)波反射传播模型。模拟电力绝缘子层间气隙,制作了橡胶-环氧树脂板层间气隙缺陷样件。对含有层间气隙缺陷的样件的波形进行分析,能够检测厚度为100μm的层间气隙缺陷,并对层间气隙厚度进行了计算。经数显千分测厚仪验证,THz检测层间气隙厚度的准确率达到95.61%。对缺陷样件进行能量积分成像并采用最大类间方差(Ostu)二值化方法提取气隙缺陷,为了验证THz检测的识别准确度,采用光学三坐标扫描仪对粘接缺陷重构提取缺陷面积,检测准确率达到95.29%。本文研究为电力绝缘子中含有层间气隙缺陷的检测提供了新方法。

Power insulators are widely used in the electric power field owing to their high mechanical strength,crack resistive surface,and slow aging speed.A terahertz wave reflection propagation model with three layers of power insulators is constructed to study the air gap between layers of power insulators.An air gap defect sample of rubber-epoxy resin plate was fabricated by simulating the air gap between layers of power insulator.The waveform analysis of the samples containing the interlayer air gap defects reveals that the thickness of the interlayer air gap defects is 100μm.Moreover,the thickness of the interlayer air gap is calculated.The accuracy of THz detection of the interlayer air gap thickness is 95.61%,as verified by a digital display thousand meter.The energy integral imaging was performed on the defect samples and the maximum between-class variance(Ostu)binarization method was used to extract the air gap defects.To verify the recognition accuracy of THz detection,the optical coordinate measuring machine(CMM)3D was used to reconstruct the bonding defects and extract the defect area,and the detection accuracy is 95.29%.This study provides a new method for detecting interlayer air gap defects in power insulators.