A new method of fault diagnosis for HV circuit breakers based on wavelet packet

Based on the theory of wavelet packet for signal analysis, a new method to diagnose mechanical fault for circuit breakers is presented. Firstly, vibration signal after noise removing is wp-decomposed at the fourth level, and the signal of each junction at the fourth level are reconstructed; Secondly, the characteristic vector is extracted with the proportion of envelope energy of each two junctions at the fourth level, while the each two junctions have an father node at the third level; lastly, the classification of characteristic parameters is realized with simple BP neural network for fault diagnosis. The experimentation without loads indicates the method can easily and accurately diagnose the mechanical faults of circuit breakers, and provide a new road for fault diagnosis of HV circuit breakers.