earthing cable at transformer star point and 51G relay

[Jed057]

We had power transformer Delta/Y 11kV/6.6 kV and supply to 6.6 kVSwitchger.
Due to in 6.6kV switch gear without netrual busbar,
Please advise that we need to connect earth cable at transformer star point or not?AND THE RELAY 51 G Is required for VCB at 6.6 k V downstream or not?
Relay 50/51 and 50N/51N shoud be enough,isn`t it.

Thanks fro any guru

 

[davidbeach]

It depends. Many options, some based operational decisions, some based on engineering preferences, others based on local custom.