480V Generator - step-up to 12kV

[EE123]

Hi,

We are trying to back up a 12kV service with 480V Generator. We have a 12kV-480Y/277V transformer that we are utilizing. The question is if we need to extend the neutral conductor from the generator to the transformer?

Thanks in advance

 

[waross]

Is the 12 kV side delta or wye?

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[EE123]

the 12kV side is delta.

 

[waross]

You may be able to leave the neutral floating, but the generator will be better able to handle unbalanced loads if the neutral is connected.
How far / how expensive will it be to add another conductor?
Is there any possibility that you can back-up on the 480 Volt side?
The transfer switch will be much cheaper.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[RRaghunath]

Presuming the generator is directly connected to transformer, there is no need to connect generator neutral to the transformer neutral.
Pay attention to the neutral earthing in 480V system - whether you earth at transformer or generator!
It is best to earth at the generator and leave the transformer neutral floating. This will limit the current that the generator will experience in case of earth fault in the generator stator windings, to a lower value and thus reduce chances of core burning.

 

[EE123]

@Waross: Thanks for the feed back. There is a considerable cost to run the neutral.

@ RRaughunath - Correct the generator is directly connect to the step-up transformer. The plan is to Earth at the generator. Thank you!