Research on Test Method of Opening and Closing Time of High Voltage Circuit Breaker Based on Wavelet Transform and Change-Point Detection Under Double-End Grounding Condition

As a key power system equipment, a circuit breaker’s opening/closing time is a core index for evaluating its performance and mechanical state. Traditional testing methods have drawbacks such as requiring ground wire removal, low safety, and susceptibility to electromagnetic interference.This paper proposes a new method for testing high-voltage circuit breaker opening/closing time based on wavelet transform and Pettitt change point detection. In this method, a test circuit is constructed under double-ended grounding, with a 40 kHz high-frequency test signal generated by a high-frequency power supply. A Hall sensor acquires loop signals, which are transmitted to an industrial computer via a data acquisition card. DB2 wavelet transform performs time-frequency analysis to effectively extract high-frequency signals and avoid interference; combined with the Pettitt change point detection algorithm, it accurately locates opening/closing times (signal mutation points). Opening/closing times are calculated using the time difference of action signal mutations.Tests on the ZF27–1100 L circuit breaker show good agreement with traditional DC resistance method results: maximum opening time error < 5.2% and closing time error < 1.0%, verifying the method’s accuracy and effectiveness. This method eliminates the need for ground wire removal, improves test safety and efficiency, and provides reliable technical support for high-voltage circuit breaker mechanical characteristic detection.