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8 comments
Active Contributor

Join Date: Oct 2011
Posts: 12

Neutral Connection In Generator Paralleling

01/18/2012 5:15 PM

Hello

I am planning to connect the neutral of the entire three synchronized cat 608 kva similar generator set on the common ground bus bar (the ground will also be connected to the bus bar) without any neutral- grounding contactor (this is because I am using 3 pole contactors for the main synchronization). I have tried to gather information about this idea on the internet and I have seen different ideas posted which contradicts. Will this create problem?

Please advise me from practical point of view.

If it is possible advice me, any ways which could avoids the possible risks without using the neutral contactor

Thanks in advance

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Join Date: Oct 2009
Posts: 2015
Good Answers: 163
#1

Re: Neutral Connection In Generator Paralleling

01/19/2012 5:36 AM

Are you earthing the neutrals of the generator solidly or with an impedance? Are the generators wound to the same pole pitch?

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#2
In reply to #1

Re: Neutral Connection In Generator Paralleling

01/19/2012 8:33 AM

<Cut to deer in headlights look here>

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Guru

Join Date: Dec 2010
Posts: 1701
Good Answers: 38
#4
In reply to #2

Re: Neutral Connection In Generator Paralleling

01/19/2012 4:30 PM

I'm just going to start giving you GA's instead of making up my own inside jokes...is that okay?

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Active Contributor

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Posts: 12
#3
In reply to #1

Re: Neutral Connection In Generator Paralleling

01/19/2012 3:54 PM

hello all

yes i will ground the neutral solidly without any impedance and the two generators are simlar (the same brand ,model,kva,we bought them together) so i think they do have the same pole pitch

best regards

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#5
In reply to #3

Re: Neutral Connection In Generator Paralleling

01/19/2012 8:52 PM

Then you may very well connect the neutrals together, without the need to isolate them. But, ensure that the phase bus bars are sized for withstanding the combined contribution from all the generators in parallel, during a single-line-to-ground fault on the bus, for, a generator's single-line-to-ground fault current may exceed the three phase fault current, due to the low zero sequence impedance of generators.

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Join Date: Jan 2008
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#6

Re: Neutral Connection In Generator Paralleling

01/20/2012 1:02 AM

And you have the sync-up procedures down pat without blowing something up, or getting into a hunting situation. Right?

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Active Contributor

Join Date: Oct 2011
Posts: 12
#7
In reply to #6

Re: Neutral Connection In Generator Paralleling

01/23/2012 12:44 PM

thankyou all for your supportive answers

and i know about the sync procedure

best regards

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Commentator

Join Date: May 2012
Posts: 56
#8

Re: Neutral Connection In Generator Paralleling

05/16/2012 2:39 AM

yes you need to connect that neutral from the individual genset to the bus bar together, then from the genset you need to have a bonding wire from nuetral to a genset body ground to protect your gen person and your machine incase of direct ligthing, always connect the individual neutral of the synchronized genset even they are in same name plate capacity to avoid reverse voltages!!!

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