Meng Yongpeng,Jia Shenli,Rong Mingzhe
(State Key Laboratory of Electrical Insulation for Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China)
Abstract:Based on the algorithm of wavelet packets,the vibration signals during the operation of circuit breakers were decomposed into the individual frequency bands£®The variations of the signal energy in these bands reflect the different mechanical conditions of circuit breakers£® Main energy ingredients were extracted to form the eigenvector for condition monitoring and the tolerance range of the eigenvector was determined by the test results under each condition£®These tolerance ranges supplied the quantified standard for condition monitoring of the circuit breaker£¬and a simple classification of the mechanical conditions was implemented consequently.The vibration signals of a ZN12-35 type vacuum circuit breaker under specific closing simultaneity were recorded from a single vibration sensor mounted on the mechanism box. After the wavelet packet decomposition,different closing simultaneities distributed in the individual areas of a complex plane can be apparently distinguished£¬ which verifies the feasibility of the proposed method applied to the condition monitoring of circuit breakers.The repeated tests indicate that the wavelet packet decomposition has a high monitoring accuracy based on a stable measurement system£®
Keywords:wavelet packet;eigenvector;frequency band energy;condition monitoring