Dynamic analysis of submerged transformer winding using laser Doppler vibrometer

The noise of the power transformer consists of numerous phenomena's that are related to vibrations of transformer core and windings as origins and secondary sources like tank, radiators or enclosures. The final noise radiation is caused by the secondary sources vibrations however study on the origin of transformer vibrations results in more efficient noise optimization in the final design. The work that is presented shows advanced vibroacoustic analysis of the transformers winding which is, beside core, the main source of noise in power transformers. Load current in the windings of transformers generates electromagnetic forces which act in both axial and radial directions in the windings. In consequence harmonic vibrations are generated, and the fundamental harmonics dominate the vibration spectrum. The technique of measuring those vibrations on energized winding in air but also immersed in transformer oil is presented and analyzed. Measurement result on real object are also valuable input for numerical model validation where modifications can be introduced and tested.