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Anonymous Poster

# Over Excitation and Under Excitation of Generator.

04/04/2008 6:44 AM

dear all

pl tell me in detail about over and under excitation phenomina of generator .ease what are the condition for the same and what will the effect on system when this occure .

regards

suresh kumar paliwal

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Commentator

Join Date: Mar 2008
Location: South Texas - SOMETIMES
Posts: 89
#1

### Re: over excitation and under excitation of generator

04/04/2008 7:55 AM

over & under excitation are related to voltage output of gen set..

overexcite generator and you will send system into overvoltage condition..

underexcite gen anf you will send system into undervoltage condition..

There is a bit more to it than that but in lamens terms that is the basics of it.. I would suggest you do some reading about voltage regulators, and generator excitation systems..

Anonymous Poster
#3

### Re: over excitation and under excitation of generator

04/06/2008 6:10 AM

dear sir

thanks for nice and early reply on over and under excitation protection.as per your reply meaning of under and over excitation is related to generator termianal voltage but in protection theory over and under excitation phenomina is devoleped by reactive power ,power factor and stator current of generator .but how can this factor affect the excitation and condition create of over and under excitation of generator .

if possible clear my doubt.

regards

suresh kumar paliwal

Guru

Join Date: May 2008
Posts: 1796
#4

### Re: over excitation and under excitation of generator

04/12/2013 5:11 AM

Dear Mr. ekiechle,

I want to supplememnt to your views.

The Power Factor will be low when Under Excitation is experienced, and Viseversa. Beyond Saturation Point of Magnetisation Caracter - over excitation will not take place.

AVR will be put in to strain - beyond a particular limit, leading to tripping of Circuit Breaker.

DHAYANANDHAN.S

Power-User

Join Date: Aug 2007
Location: San Francisco Bay Area
Posts: 269
#2

### Re: over excitation and under excitation of generator

04/04/2008 8:16 PM

Suresh,

Here is some material from Basler that has good information:

You will also find alot of good information here:

http://www.basler.com/html/dwntech.htm

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