Metering CT for protection

[electrolitic]

I think that a metering CT can be connected to a protection ground relay if installed at HRG circuits of transformers and generators.
I can see some pros and no cons. Am I right? Is this feasible/usual? Thanks.

 

[davidbeach]

If it costs anything more than the protection CT that would normally be used then there's that downside. That would be about the only place you could use metering CTs for protection.

 

[electrolitic]

I am not sure if costs more. I will check it. Accuracy is better, no need of high dynamic and thermal capabilities, possibility of very low setting points (less than 10% of CT nominal current), less weigth and reduced dimensions. Really, is the only place, I guess, that I could use metering CTs for protection. Considering your answer, it is not usual. Thanks.