Research On The Vibration Analysis Method In Detecting The Condition Of Transformer Winding Under Sudden Short-circuit Impact

Winding fault is one of the main transformer faults and is mainly resulted from the sudden short-circuit, the winding is likely to be loose or deformed after the sudden short-circuit. Research and analys is show that looseness and deformation of winding have accumulative effect, and it will cause serious fault in transformer if the transformation accumulates to a certain stage. Therefore, making an assessment timely and effectively on transformer winding state is substantial in improving power system stability as well as the key factor in developing smart power grids.The artic le comes up with a detection method of mechanical state in transformer winding based on transient vibration waveform analys is of short-circuit impact in transformer according to the analysis of transformer vibration mechanism. Vibration method estimates the winding state by analyzing the vibration signal of transformer tank, it has no electrical connection with transformer compared to traditional frequency response analys is, short circuit impedance method and low voltage impulse, which is a safe, precise and sensitive way to realize online monitoring, and can evaluate transformer winding state timely and precisely.Firstly, the artic le established axial vibration model of transformer winding by analyzing the structure of transformer winding, the character of winding vibration acceleration and the connection of its mechanical structure is analyzed along with the study of transient vibration characteristics of power transformer winding under the short-circuit impact.Secondly, the article comes up with a new analysis method of vibration signal: complex wavelet time-frequency analytics, by applying the proposed method and the time-domain analysis of vibration severity and vibration intens ity index that established an evaluation index for winding state as its criterion.At last, by analyzing the experimental results of short-circuit impact of a set of 10 kV transformer, the time-frequency domain of vibration signal under the short-circuit impact is obtained as well as the variation of vibration intens ity, an analysis is carried out by applying the detection metho d suggested in the artic le, the result shows that the transient vibration analys is is a simple and effective method to test the mechanical state of transformer winding, and it ensures a higher sensitivity involves in testing the looseness and transformation of winding.The results of this research provide a theoretical basis for the monitoring technology of transformer winding deformation based on vibration analysis.