Directional relay (Forward / Reverse) Set up 2

[NickParker]

How should the directional relay (forward/reverse) be set up when cross tie feeders are connected to Switchgear A and B on both ends?

 

[davidbeach]

Throw in a bit of comms and run a POTT scheme between the ends. Or go with 87L. SEL has a new, relatively inexpensive (at least compared to the top end line diff) two terminal 87L for just such applications.

When one this sentence into the German to translate wanted, would one the fact exploit, that the word order and the punctuation already with the German conventions agree.

-- Douglas Hofstadter, Jan 1982

 

[wcaseyharman]

It depends on when you want to trip for an overcurrent situation. For example, if the bus is equipped with differential protection I’d recommend setting it forward. If there’s no differential element on the bus, you would want to trip for both directions.

 

[RRaghunath]

The Directional relays are for fast clearance of any faults in the interconnector. Hence, the protection shall be set to look in forward direction at both ends of the interconnector, in other words looking away from the busbar and towards the interconnector.

R Raghunath

 

[NickParker]

If there’s no differential element on the bus, you would want to trip for both directions.

Are you suggesting to use non directional element if there is no differential protection?

 

[wcaseyharman]

No, I was thinking too narrowly, the subsequent post made me realize my error. The main benefit I see by using directional is for a “through fault” (a fault that is not in that line but fault current is flowing for a fault nearby) only one of the two breakers will trip. That will likely make restoring service a little easier and faster.