Transformer core was not grounded by a mistake!
Transformer core was not grounded by a mistake!
(OP)
Hi all
Does any of you have some comments on what if a transformer core was not grounded by a repair factory;s mistake? What are the potential risks if leave it as it was shipped and put into service? The xfmr is a 20/33/37MVA, Y-Y, 27.6-13.8kV unit.
Thanks in advance!
Does any of you have some comments on what if a transformer core was not grounded by a repair factory;s mistake? What are the potential risks if leave it as it was shipped and put into service? The xfmr is a 20/33/37MVA, Y-Y, 27.6-13.8kV unit.
Thanks in advance!






RE: Transformer core was not grounded by a mistake!
For bigger transformers (all types), I don't know. I'm hoping to get some anwsers here like you.
RE: Transformer core was not grounded by a mistake!
1 - If core not grounded, the first fault that may occur upon weakening of insulation would be phase to phase fault instead of phase to ground fault. Fault current associated with phase to phase can be higher. It may be harder to protect against (although differential should work). And it causes more damage.
2 - Grounded core results in known voltage stress distribution. You can put the stress where you want it.. mostly in the insulation. Ungrounded core can result in more unknowns in the voltage stress distribution, especially during transients.
3. That's the way it's always be done (?)
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RE: Transformer core was not grounded by a mistake!
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Eng-tips forums: The best place on the web for engineering discussions.
RE: Transformer core was not grounded by a mistake!
Regards
Marmite