Reactors on Substation Feeders

[rockman7892]

I was recently looking at a utility Substation that had 13.8kV MetalClad Switchgear with a double bus / double breaker arrangement which had reactors on each of the outgoing feeders. The reactors appear to be 1.5ohm/400A, 1.5ohm/600A and 1ohm/600A combos.

Are these reactors used simply for limiting fault current at the feeders downstream location or is there perhaps another reason why these reactors may be used?

 

[rockman7892]

I forgot to include this Switchgear is fed from two 56MA 69/138-13.8k transformers.

 

[davidbeach]

Probably fault current limiting, but there's not enough information to evaluate the situation and determine other possible uses.

 

[Mbrooke]

Usually to limit fault current, sometimes to help over current devices coordinate. There might be other reasons. Around me when 13.8kv and 23kv substation transformers are run with their secondaries paralleled (bus tie breaker(s) normally closed) the feeders are equipped with reactors to keep the fault current under 12.5ka. Most distribution equipment is rated for 10,000 amps max, so keeping the current at and below that level is necessary.

 

[JJHorak]

Maybe they are related to closed transition of two sources feeding an important load.

J. Horak, P-R Engineering, Colorado