Study on Hydrophobicity Detection of Composite Insulators of Transmission Lines by Image Analysis

Hydrophobicity of the composite insulators is a parameter which is closely related to the insulation properties. In order to determine whether the insulator in the transmission line needs to be withdrawn, it is necessary to objectively and accurately determine the hydrophobicity grade of the composite insulator. The study on hydrophobicity detection of composite insulators of transmission lines by image analysis is proposed in this paper, by which the hydrophobicity of composite insulators can be measured timely. The grayscale, median filtering, and histogram equalization of the hydrophobic images are fulfilled sequentially, and the water drops (or water marks) region is segmented by binary large object analysis and four parameters related to water repellency are extracted. In addition, the improved support vector machine algorithm is adopted to calculate the hydrophobicity of composite insulators. The results show that seven typical hydrophobic levels of insulators can be recognized by the proposed hydrophobicity detection method whose accuracy is more than 91%.