High voltage circuit breakers are one of the most critical electrical equipment in power grid. Once a faultoccurs

it will seriously threaten the safety and stable operation of the power grid. Therefore

research on high volt-age circuit breaker fault diagnosis methods has practical engineering value. In order to avoid the complicated calcula-tion of the vibration characteristic quantity

this paper proposes a high voltage circuit breaker fault diagnosis methodbased on wavelet transform and analysis of vibration start time. Wavelet transform and abrupt signal start point extrac-tion methods are used to start the vibration signal of the circuit breaker. Extraction of feature quantities at time;faultanalysis of circuit breakers using fingerprint initiation time as fingerprint features improves calculation speed and fea-ture extraction accuracy. In the laboratory

the method is used to deal with and analyze the Analog voltage fluctuationfault and the opening solenoid fault. The results show that when the overall deviation of the vibration start time is with-in the range of-2 ms to 24 ms

it can be determined that the operating voltage of the circuit breaker is within a reason-able fluctuation range. If it exceeds this range

it indicates that the circuit breaker is more likely to fail;at the sametime

the defect that the gap between the dynamic and static iron cores caused by the loosening of the opening sole-noid core can be diagnosed

thereby verifying the correctness and effectiveness of the method.