Grounding Transformer Requirements
Grounding Transformer Requirements
(OP)
I want to develop a 25 ampere resistance grounded system for a delta connected 7.2 kV supply. I want to use three single phase transformers (4160/7200V to 480 volt)to serve as a grounding transformer. The transformers will be connected wye-delta with the grounding resistor connected to the neutral on the wye side. There will be no load connected to the 480 volt delta secondary. The system components must be rated for continuous duty, not short time duty. What is the proper size for the bank of transformers - 100 kVA or 300 kVA?
Dave
Dave






RE: Grounding Transformer Requirements
Bill
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"Why not the best?"
Jimmy Carter
RE: Grounding Transformer Requirements
RE: Grounding Transformer Requirements
RE: Grounding Transformer Requirements
Thus the power of the transformer will be:
Nt= 4160 * 25 = 100kVA
some people prefer continuous rating of the grounding transformer , because sometimes during operation ground earth protection trip wrong.
They change for alarm while investigate the problem.
.
RE: Grounding Transformer Requirements
P = 25/3 * sqrt(3) * 7200 = 104 ~ 100kVA