Abstract: In order to reduce the risk of composite insulator defects on the safe operation of the power grid, the ultrasonic detection technology is carried out for the composite insulator defects with a radius of curvature of 13 mm, and the ultrasonic characteristics of the three defects are swept and analyzed through the special 3 mm single crystal, 5 MHz straight probe and sheath three different types of composite insulators simulating uneven thickness,porosity, and debonding defects. The results demonstrate that the method can effectively detect the defects of uneven thickness, porosity and debonding, in which the measurement accuracy of sheath thickness is 0.3 mm, the detection sensitivity of porosity defects is 2 mm in diameter, and the positioning accuracy is 0.4 mm and the detection of debonding defectsis characterized by the disappearance of the reflective wave at the interface of the adhesive. The detection method is highly efficient and can enhance the flexibility and practicality of on-site inspections.

Key words: power insulation, composite insulator, ultrasonic testing, simulated defects