Fuse Protection for Grounding Transformer 1

[NickParker]

The Vendor has proposed a fuse protection for a grounding transformer. My concern is if the fuse blows, we would lose the grounding.

Thank you!

 

[RRaghunath]

Yes. Fuse here is more as a back up protection for the Power contactor as the contactor is not designed to interrupt large fault currents.
Resistive faults / low current faults including SLG faults can be cleared by the protection relay / power contactor.
For massive faults with large fault currents fuses blow.
When any of the three fuses blow, a switch is operated which will be wired to open the power contactor as well as alert the operator.
Now, the 11kV system is without earth reference which is not acceptable / safe scenario. Operator is supposed to act to shut down the bus in a planned way or utilise the grounding transformer of other bus section (presuming there is another bus section with its own grounding transformer).