Characteristic parameter change of circuit breaker under closing spring fatigue

Abstract

Closing spring fatigue faults of high voltage circuit breakers affect the timing parameters in closing operations and reduce the closing performance of the circuit breaker. Traditional tests of timing parameter based on travel curve cannot be applied online, and sensor installation is complicated. In this paper, a new method to extract key circuit breaker timing parameters from the vibration signal under closing spring fatigue fault is proposed. First, the travel curve of the circuit breaker under closing spring fatigue is simulated in Automatic Dynamic Analysis of Mechanical Systems (ADAMS). Results indicate that the time intervals between key points of the travel curve can be used as fault features. Then, according to the working principle of the circuit breaker’s spring operating mechanism, the vibration event caused by component impact in the closing operation is analyzed. The corresponding timing parameters are extracted from the vibration signal using the double threshold method based on the short-time energy to entropy ratio. Finally, comparison of experimental measurements with ADAMS simulation results and vibration extraction provides the change law of the fault feature. The correctness of the proposed method is verified. This paper presents a new method for online monitoring of circuit breaker closing spring fatigue.