In order to realize real-time monitoring on transformer working condition

and find out breakdowns timely

it is needed for transformer core-winding vibration simulation to determine the optimal measuring point according to vibration. So use finite element analysis（ FEA） method on modal characteristics of S13—12500/35 type of oil-immersed power transformer core-winding in clamping state and loose state

and contrast amplitude-frequency characteristics of core-winding vibration in clamping state. The simulation results show that the strongest position of core-winding vibration mainly distributed in clamp center and the four sides of lower surface angle of the left and right and the middle of upper iron yoke and the u

pper part of the three-phase windings. The main response frequency band is above 300 Hz under normal preload

amplitude spectral energy is concentrated at 100 Hz and near 300

350 Hz. It provides a theoretical basis for selecting of measuring point and setting of threshold of the transformer vibration.