Transformer protection with OLTC voltage cont. option

[slavag]

Hi All.
I see today, that lot of numerical transformer protection
relays are also included OLTC voltage control option.
We installed relays with this option,is work fine, but not all customers and designers agree with us.
What is your opinion?
Thanks.
Regards.
Slava

 

[PUNGLU]

I tend to think that for reliability the relays they should not be incorporated together. The voltage relay using the line voltage to obtain the reference signal, with the tap-changer having contactors that could fail anytime; from experience, the circuits for the numerical relay and the voltage regulating relay I suppose must be well isolated!!