One and Half Breaker Bus Bar Mode

[Kiribanda]

Dear friends!

This is about a MV power distribution system. I have seen a “ One and Half Breaker “ bus bar arrangement in an open outdoor switchyard operating at 115 kV having two in-house gas turbine generators, two utility feeders and two load feeders serving a co-generation plant.

1)Is it technically possible (due to breaker arrangements etc) and economically viable to have the same bus bar arrangement (1 ½) in an INDOOR substation at medium voltage level?

2)Any member has any comments on such a bus bar & switchgear arrangement as far as its mode of operation is concerned?

3)Can any member suggest alternate bus bar arrangement for such a power distribution system at MV level?

Thanks in advance!
Kiribanda :->

 

[jbartos]

Suggestions marked ///\\\:
This is about a MV power distribution system. I have seen a “ One and Half Breaker “ bus bar arrangement in an open outdoor switchyard operating at 115 kV having two in-house gas turbine generators, two utility feeders and two load feeders serving a co-generation plant.

1)Is it technically possible (due to breaker arrangements etc) and economically viable to have the same bus bar arrangement (1 ½) in an INDOOR substation at medium voltage level?
///It is technically possible; however, not economically viable. Why to house equipment that is designed for outdoor?\\2)Any member has any comments on such a bus bar & switchgear arrangement as far as its mode of operation is concerned?
///D.G. Fink, H.W. Beaty "Standard Handbook for Electrical Engineers" 14th Ed., 2000, lists on page 17-5:
1. Either bus may be taken out of service at any time without loss of service.
2. With sources connected to opposite to source, it is possible to operate with both buses out of service.
3. The breaker and half is more expensive than other schemes except double breaker, double bus, and protective relaying and automatic reclosing scheme.
4. Etc.\\3)Can any member suggest alternate bus bar arrangement for such a power distribution system at MV level?
///Yes. For example, the double breaker is better; however, it is more expensive.
If the cost is the factor, then the single bus is the least expensive one.\\\

 

[jwerthman]

The breaker-and-one-half configuration can be implemented with indoor switchgear, but it is not commonly done due to cost. It has the same advantages as for an outdoor substation. It is more difficult to construct within the constraints of enclosed switchgear, but not impossible. I have seen it a few times.

 

[RRaghunath]

To my knowledge, double bus scheme seems more common at MV level for generation busbars. I have come across in a few process plants with in-house generation.