The stability of the mechanical structure of transformers plays an important role in the safe operation of entire power grid. As one of the common faults of transformers, minor winding deformation cannot be easily detected and its effects are cumulative. This paper focuses on vibration characteristics of transformer windings under deformation conditions to provide a basis for transformer fault diagnosis. We have developed a finite element model of a three-phase transformer to simulate and to calculate the distribution of winding electromotive force, based on which the winding deformation trend is predicted. We designed three types of deformation. The winding axial vibration signal characteristics were studied in detail under different degrees of deformation. The simulation results show that the maximum force is applied to both ends of the winding, meanwhile the high and low voltage windings are subjected to outward expansion force and inward compression force respectively. When the winding is deformed, the frequency distribution and amplitude of the vibration signal will be changed.

Transformer windings deformation,axial vibration signal,fault diagnosis