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What is the %Z of this grounding transformer given this nameplate data ?

bdn2004

Electrical
Joined
Jan 27, 2007
Messages
810
Location
US
Below is the picture of the nameplate.... as you can see Z0 = 97.14 ohms per phase. Or can this be figured out from this info ?
If so what is the calculation ?

Grounding Transformer.JPG
 
It seems the subject transformer is meant to be used as Grounding transformer only.
Since there is no load that is going to be connected on secondary side, %Z is not relevant and hence not marked on the name plate.
Zo and the expected ground fault current is relevant and has been marked.
 
It actually does have load on it ... Aux Power they call it. It's connected to a 3-phase switchboard.

I've tried to draw out a completed faulted circuit to ground downstream on Phase B. Do I have this right ?

The ratings on this transformer appear to be rated currents for normal operation.
29A continuous phase current = FLA of the transformer
87A continuous neutral current = Approximately 3 x FLA
300A for 10 seconds, max rating.LRG Transformer Circuit jpg.jpg
 
There's nothing connected to the delta winding, so no load on the transformer. It supplies ground fault current during ground faults.
 

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