Transformer Configuration

[DMG_1]

I have a question regarding transformer configurations. I am working on a project where we are changing a generator from 2400 V to 480 V and adding a step up transformer. The details are as follows:

1. The utility has 2400 V attached to one side of an ATS fed from (3) 100 kVA single phase transformers.
2. The 2400 V generator attaches to the second side of the ATS.
3. The load consists of 12 small buildings and is fed by the ATS.

The customer wants to change out the 2400 V generator because they have a tough time getting spare parts. We are going to swap the generator out with a 480 V generator and add a 480 / 2400 V step up transformer.

My question is, what should be the configuration of the transformer, wye-delta or delta-wye? I assume we would simply match the configuration of the utility transformer but are there general rules of thumb dictating transformer configurations?

 

[masterinbama]

Set your generator for 480 3 phase Delta, or wye and leave the neutral open and isolated.

Use a 2400 to 480 delta delta in reverse.

 

[hurk27]

I have a question regarding transformer configurations. I am working on a project where we are changing a generator from 2400 V to 480 V and adding a step up transformer. The details are as follows:

1. The utility has 2400 V attached to one side of an ATS fed from (3) 100 kVA single phase transformers.
2. The 2400 V generator attaches to the second side of the ATS.
3. The load consists of 12 small buildings and is fed by the ATS.

The customer wants to change out the 2400 V generator because they have a tough time getting spare parts. We are going to swap the generator out with a 480 V generator and add a 480 / 2400 V step up transformer.

My question is, what should be the configuration of the transformer, wye-delta or delta-wye? I assume we would simply match the configuration of the utility transformer but are there general rules of thumb dictating transformer configurations?

I would contact the engineering department of the generator manufacture as you might have problems with the voltage sensing configuration and any single phase/brown out detection circuits that may be a part of the generator controls even if you keep the 2400 volt ATS, also the inrush to the transformer might be a problem.

What is the end load voltage at each building and is the 2400 volts to over come voltage drop because of long runs? back feeding a transformer will have a much higher inrush that can cause problems.

Might want to look at setting smaller generators at each building to only supply the buildings that need back up.

Also have you looked at the cost of having a 100kva transformer online all the time? its not cheap.