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Anonymous Poster

Generator NGR resistance

09/11/2008 4:02 AM

Dear sir,

The NGR value of a 11KV 8.5 MW generator is 1270 ohm. How to derive the above resitance value or what is the procedure and can we find charging current from the above value. Kindly please clarify.
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Anonymous Poster
#1

Re: Generator NGR resistance

09/11/2008 8:57 AM

I=11000/(1.73 X 1250)= 5 A ,
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jack of all trades
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#2

Re: Generator NGR resistance

09/11/2008 3:39 PM

What to you mean by derive (do you mean how to size a NGR for an application)? It's a neutral grounding resistor.

Neutral grounding resistors don't "charge". Do you actually know what a neutral grounding resistor is and why it is used?

Could you explain you question more thoroughly please.

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Flux
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#3

Re: Generator NGR resistance

09/12/2008 1:09 AM

I think he means NGR's charging current during normal operation. It is dependant of the system capacitance to the ground and thus must be calculated (there are also some tables ready for this).

The above 5A is not the charging current but the resistive fault current. More NGR stuff in linky:

http://www.startco.ca/library/papers/PowerTestPaper.pdf
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