Grounding Resistor w/downstream regulators 1

[lkincer]

I have a question about metering PT's at an industrial substation, 115-13 KV, with two 12 MVA, delta-wye transformers that are grounded through 35 ohm resistors.

The power supplier says their normal practice grounding the metering PT's through the grounding resistor.

These makes me very nervous since I think we would see a large voltage buildup during a fault or severe unbalance.

Another power supplier says that they simply connect the PT's directly to ground.

What's your opinion.

Thanks,

 

[jghrist]

I would think that you would have to use two-bushing VTs for a wye connection and connect the neutral point to the neutral to get a true meter reading. Either that or connect them delta.