In order to analyze the distribution characteristics of the natural frequency of the transformer winding and to identify the axial compression state of the transformer winding compression state online

we established the transformer winding leakage field model

and analyzed the ampere force distribution of transformer windings based on the circular current spatial magnetic field distribution. Then

we proposed static-force analysis of line cake

considering the influences of the preload

gravity

and Ampere force axial components on the transformer windings natural frequency. Finally

we analyzed the dynamics response and the motional electromotive force of transformer winding introduced by the electromagnetic force. The results show that the natural frequency of the transformer winding has the following characteristics: under the action of axial ampere force stability

the natural frequency of central windings increases and the natural frequency of windings at both end sides reduces. The interaction of axial vibration（100 Hz） of transformer winding and leakage magnetic field（50 Hz） can produce motional electromotive force with frequency of 150 Hz and 50 Hz which will hinder the flux change.