actual directional earth fault relay connection

[tamerelminshawy]

السلام عليكم ورحمة الله وبركاته

Dear brothers
Attached file shows actual wiring for directional earth fault protection relay.
This relay is set to trip in the forward direction with V, I angle = 15
according to the wiring you will see that the earthing point of the C.T secondary is towards the transformer. This as far as I know means that the forward direction is when the earth fault current follows towards the transformer.
I hope that you will find this usefull and I hope to receive your comments

My deep regards to you all

[Shaltoot]

السلام عليكم ورحمة الله وبركاته

Dear brothers
Attached file shows actual wiring for directional earth fault protection relay.
This relay is set to trip in the forward direction with V, I angle = 15
according to the wiring you will see that the earthing point of the C.T secondary is towards the transformer. This as far as I know means that the forward direction is when the earth fault current follows towards the transformer.
I hope that you will find this usefull and I hope to receive your comments

My deep regards to you all

The point of earthing has no significance

What determine the forward direction of the CT is the location of P1 and P2 (P1 is usually marked by a black dot on the window CT

The forward direction is when the current flows from P1 to P2 marks

Accordingly the relay must be connected to S1 and S2 respectively

By the way most modern digital relays have an internal setting ( LOAD/SOURCE

[tamerelminshawy]

The point of earthing has no significance

What determine the forward direction of the CT is the location of P1 and P2 (P1 is usually marked by a black dot on the window CT

The forward direction is when the current flows from P1 to P2 marks

Accordingly the relay must be connected to S1 and S2 respectively

By the way most modern digital relays have an internal setting ( LOAD/SOURCE

Dear Eng. Shaltoot
Many thanks to your valuable comments and I amy sorry that I caused you much trouble
According to the wiring K point on the C.T primary is connected to the 33 kV side and the L point is connected to the 10.5 kV side.
and since the protection relay is adjusted to trip in the forward direction then it will trip when fault current flows from the 33kV side downwards to the 10.5 kV