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Anonymous Poster #1

Transformer Details

02/10/2012 3:36 AM

1..Could someone tell me in details why transformer with (15MVA...) sound????i dont know technical reasons??why generator transformer with the same specification never sound???

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Associate

Join Date: Jun 2009
Posts: 49
#1

Re: TRANSFORMER DETAILS

02/10/2012 4:01 AM

It is due to " magnetostriction effect".

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Guru

Join Date: Dec 2010
Posts: 1668
Good Answers: 115
#2

Re: Transformer Details

02/12/2012 6:00 PM

Just going on memory here - a generator transformer has a much higher operating voltage margin above normal voltage than a "normal" transfo. I think there is a supplement to standards applicable to generator transfo service.

A system or generator load shedding causes a (temporary) generator voltage jump which could overflux the transfo, causing high magnetization current (which causes transfo differential relay to trip).

Consequence is normal working flux density is lower in generator transfo - this reduces magnetostriction acoustic noise compared to a distribution transfo.

Another factor may be higher harmonic currents in the load of the distribution transfo - higher frequency sounds are more audible - the ear is more sensitive to 300 Hz than 100 Hz.

You could try recording the sound with a laptop computer and microphone [at 1 metre distance, say, from each transfo, similar location] and compare the levels/frequencies by doing a Fourier analysis on the recorded file. Many "spreadsheets" have a Fourier analysis function.

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