Series reactor question

[cranky108]

I knew this last week, but I have had people telling me other things, and I need a voice of reason to get me back on the right answer.
I proposed a high impedance differential for protection of a series reactor.

I have since had people telling me that I need a low impedance differential to handle in-rush. I don't see that there is any in-rush as there is only about 30 feet between the breakers, and not that much capacitance. Also there is no ground connection, not even a PT proposed, so I don't see it there.
I don't think I am missing anything, or am I?

It should have no impact from what is on either side of the reactor, but is outside the differential zone. Over head line, underground line, should make no difference.

It is not helping that we are also installing a shunt reactor at a different substation.

 

[RRaghunath]

I can understand inrush for shunt reactor or a transformer. Series reactor is part of the interconnecting line between two stations and is meant to reduce the fault level at the receiving end station.
The line protection covers series reactor as well and I don't see need for separate protection for the reactor itself, other than its own temperature protection and Bucholtz protection.

 

[bacon4life]

I not realized a series reactor would have it's own differential zone. Is it an air core reactor or an oil filled reactor?

 

[cranky108]

Air core reactor, and it is required to have a bypass. The switching of line impedance would cause issues with line relay settings, and testing. It is easer to just have in its own differential zone.
No oil relay, or temperature dials.

It is to be used to change line flows, and force more power over a higher voltage path some miles away.

 

[bacon4life]

I can see why separate zones are useful. Hopefully whoever thinks you have an inrush issue can explain in more detail what they mean.

 

[davidbeach]

Apply a 487E or a 787 and treat it as a 1:1 transformer; take advantage of the harmonic blocking. Then stick some 411Ls on the line. Piece of cake.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[scottf]

Air-core reactor would not have in-rush current.

 

[cranky108]

I think a pair of 587Z's to protect the reactor, and 311C's for the line. I don't think I need the Horsepower/speed/complexity of other relays.