Abstract: Current research on fault diagnosis of vacuum interrupters relies mainly on electromagnetic pressure analysis.However,due to the interference of electromagnetic noise and mechanical noise,the diagnostic results are often unsatisfactory.In this paper,we propose an X-ray diagnostic method based on edge Hough transform,which utilizes an X-ray imaging system to acquire the internal structure of vacuum interrupter contacts.In this paper,BM3D image denoising,image normalization,and SAMSR image enhancement techniques are combined to enhance the internal information expression of images.Due to the similarity of the vacuum interrupter structure,the edge Hough transform is used to process the contact structure image.Canny edge detection is performed on the contact area image,the Hough transform is used to select the most expressive straight line,the appropriate fault threshold is set,and the difference between the most expressive curves of the movable and static contacts is calculated.Then,the contact fault information is judged.The overall structure of the vacuum interrupter is systematically analyzed,and three different contact failure forms are illustrated.The experiment was carried out using six groups of contact failure data,and the calculated angular differences are 3.63°,4.77°,8.95°,5.15°,5.50° and 3.72°,respectively,which met the set fault threshold conditions and have good fault diagnosis effect.