MV Transformer Resistance Grounding

[kjjack]

I have a 13.2kV-4.16kV delta-wye transformer application that I am questioning whether to add low resistance grounding to. The transformer is fed by 13.2kV switchgear via a fused load-break switch (xfmr primary fuse). On the 4.16kV side, the transformer feeds another set of load-break switches, through a fused main load-break (xfmr secondary fuse). There are no relays or circuit breakers on the system downstream from the utility feed.

My question is, is there any need to have a low resistance neutral grounding system on the transformer, as there are no relays or breakers to trip?

Any help appreciated.

 

[tem1234]

Typically, the grounding resistor should be rated for a short time, like 10 second. So you have to clear the fault before 10 second. The fuse probably won't see the fault, since the fault current is small. So if you use low resistance grounding, you must have a relay and something to clear the fault quickly, usually a breaker.

 

[kjjack]

thanks. so if there are no relays or breakers, would it make sense to just have the transformer solidly grounded/