Generator Residual Protection relay

Is this an emergency generator or a stand alone power system? And why 400v?

If it is an emergency generator. Your gerenrator should be grounded with as a separately derived system, but it should also be attached to the source source ground throught your transfer switch.

If it is a stand alone power source then it should be grounded as such, and all equipment attached should be grounded per code and engineering standards.

I have never had to put a fault relay on such a small piece of equipment.

Hi, it's an emergency generator,400v phase to phase, 560KVA. The neutral point was connected to the power switchboard but isolated from the plant earth. The generator was grounded from its equiptment earth bud ( i.e body of generator ).

So I was wondering if I put a residual earth fault relay on the 4 core cable( 3 phase and 1 neutral) that ran from the generator to the switchboard, would it work?