Aiming at the problem that it is difficult to locate the impact time domain in the measurement of asynchronous time of conventional circuit breaker contacts by using vibration signals

we propose a measurement method based on modified time-reassigned S-transform. Firstly

mode relevance variational mode decomposition(MRVMD) and fast singular value decomposition(FSVD) methods are combined to preprocess the closing vibration signal

and the frequency characteristics of the vibration signal excited by the contact collision are reconstructed to highlight the effective impact characteristics of the main contact collision. Then

a modified time-reassigned S-transform is proposed to improve the time-frequency representation ability of short-term broadband signals such as contact vibration impact. Finally

combined with the maximum envelope spectrum amplitude criterion of frequency slice

the contact impact characteristics at the optimal frequency point are screened to determine the key event nodes of the main contact collision

and the three-phase asynchronous time measurement is realized. The experimental results show that the proposed method can be adopted to realize the effective measurement of different contact states

and has an engineering practicability.