Mechanical stability assessment of transformer winding by the synchrosqueezing S-transform

How to assess the mechanical stability of a transformer after short circuit impacts is essential for the safe and reliable operation of power transformers. The transformer vibration signal under sudden short-circuit impacts mainly consists of winding vibration. In this paper, the time-frequency characteristics of the transient vibration signal are obtained by synchrosequeezing S-transform (SSST). The results can be used to achieve accurate identification of the mechanical stability of transformers suffered from short-circuit impacts. The calculation results of applying this method to the short-circuit impact vibration signal of a 110kv transformer show that the time-frequency domain spectrogram obtained based on the SSST has the advantage of high resolution and strong energy aggregation. In addition, the improved time-frequency resolution of the SSST can be seen by comparing the results of the SSST and the S-transform.