Ceramic pillar insulators play an important role in ensuring reliability of electrical equipment

such as high voltage circuit breaker. In this study

the aging causes and characteristics of the ceramic pillar insulator are analyzed

and the corresponding diagnostic methods are summarized. Consequently

a flaw detection method based on vibrational acoustics was proposed for ceramic pillar insulators

which is suitable for high altitude areas in northwest region of China. Online detections of the ceramic pillar insulators in three substations were conducted with the proposed method

and the detection results were compared with that of off-line detections. The comparison verifies the feasibility of the proposed flaw detection method for ceramic pillar insulators based on vibrational acoustics.