Previous in Forum: Digital Multimeter With DC Clamp On   Next in Forum: Generator Clearance Issue
Close
Close
Close
2 comments
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???

Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Associate

Join Date: Jun 2009
Posts: 49
#1

Re: TRANSFORMER DETAILS

02/10/2012 4:01 AM

It is due to " magnetostriction effect".

Reply
Guru

Join Date: Dec 2010
Posts: 1686
Good Answers: 116
#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.

Reply
Reply to Forum Thread 2 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Previous in Forum: Digital Multimeter With DC Clamp On   Next in Forum: Generator Clearance Issue

Advertisement