Power Transformer Neutral Earthing

Were there to be a current flowing in the neutral conductor to earth, as there will be under a fault condition, and that conductor were not bonded separately to earth, then at the moment the fault current flows the earth conductors elsewhere on the network upstream of the neutral connection point would be at a voltage relative to earth equal to the fault current flowing multiplied by the cable resistance between the connection point and the earth electrode itself. As the earth conductor network is intended for personnel protection in the event of a fault, and these personnel could be referenced to earth in other ways such as their capacitance to earth, such an event might lead to an electric shock for someone touching both the earth conductor network and the other earth reference point.

Connecting the neutral to earth separately from the earth conductor network obviates this particular issue and results in the safest possible installation. Doing otherwise may be prohibited by some countries' wiring codes for that reason.

How i can Connect the neutral to earth separately ,shall i dig for a metal rod into the earth ?

Yes,the earth pit for neutral grounding is dig somewhere in the substation or power station and the earthrods are driven where the wire from the neutral terminal is to be connected.And the sub or power station earthing network which is done mainly for equipment body earthing and metal structures earthing,is done separately(i.e no direct connected wires ).

By T.Mabugo