In order to cut down the cracking accidents of in-service porcelain insulators

enhance the detectable rate and detecting velocity of a detection method

this paper proposed a vibration-based damage detection method for detecting insulators by making use of the global damage detection method.Four freely suspended or on-ground porcelain insulators were tested with an aluminum hammer activating them Vibration signal and acceleration response were analyzed respectively with frequency spectrum analysis and wavelet packet analysis to achieve fault characteristic parameter.The results indicated that a 4mm deep defect could be effectively detected by utilizing wavelet packet analysis.