Double Busbar Scheme for outdoor switch yard system (132kv)

[neduet]

Double Busbar Scheme for outdoor switch yard system (132kv) step up power plant

Hi friends
1. in this system both busbars energized all the time.
2. what is the meaning of main BB and transfer BB,
3. step up transformer connect main bus bar all the time or both BB connected through DS switch .
4.bus sectionalization means ?

thank you.

 

[Windadct]

Because of regional and language differences - a diagram or image would help. In the States we have double ended switchgear - which seems to coincide with your question, but to speculate and give info that does not really relate to your question would only be confusing to everyone.

 

[neduet]

Because of regional and language differences - a diagram or image would help. In the States we have double ended switchgear - which seems to coincide with your question, but to speculate and give info that does not really relate to your question would only be confusing to everyone.

 

[neduet]

now my question is this system both busbars energized all the time. what is the meaning of main BB and transfer BB and what is the purpose of bus coupler is it always put couple both buses all the time or its open in normal condition ?

 

[Windadct]

Thanks for the image - - are these 11KV generators with Step up Transformers? - And this is the Gen Station Transmission tie circuit.

This is a doubly fed system, and continuous service is the objective. Here (as it is drawn) when Ckt 1 and Ckt 2 DS are closed - these Transmission lines are tied together ( and assuming this is a GEN station) it can be offline completely.

So there is a possible reason for this arrangement - but it depends on the application and what were the priorities of the various lines and loads.

 

[Babadag]

An one-line diagram is better in order to understand this.
The first diagram- in my opinion-it is translated from yours.
The supply lines enter BB1 and the transformer are connected with BB2.
However, this is not the destination of a transfer busbar. The second “improved” diagram it is what actually has to be: one main bar where all the line and transformers are connected with usually and the second the transfer bar-if there is a trouble with the first one you may close the coupling breaker and to supply one or all transformers from the transfer bar.
This is a transversal coupling. If the busbar is divided longitudinally in two sections –usually in order to supply redundant equipment [transformers]- a coupling [2 disconnectors and a circuit breaker] is provided between the two sections.

 

[neduet]

Thanks for the image - - are these 11KV generators with Step up Transformers? - And this is the Gen Station Transmission tie circuit.

This is a doubly fed system, and continuous service is the objective. Here (as it is drawn) when Ckt 1 and Ckt 2 DS are closed - these Transmission lines are tied together ( and assuming this is a GEN station) it can be offline completely.

So there is a possible reason for this arrangement - but it depends on the application and what were the priorities of the various lines and loads.

yes its gen station and 11kv/132kv stepup transformers. , some one say on internet that both bus bars one line all the time so what is the benefits for using double bus bar scheme ?

 

[neduet]

An one-line diagram is better in order to understand this.
The first diagram- in my opinion-it is translated from yours.
The supply lines enter BB1 and the transformer are connected with BB2.
However, this is not the destination of a transfer busbar. The second “improved” diagram it is what actually has to be: one main bar where all the line and transformers are connected with usually and the second the transfer bar-if there is a trouble with the first one you may close the coupling breaker and to supply one or all transformers from the transfer bar.
This is a transversal coupling. If the busbar is divided longitudinally in two sections –usually in order to supply redundant equipment [transformers]- a coupling [2 disconnectors and a circuit breaker] is provided between the two sections.

thank you very much, my ckt is this, what type of faults we will over come using improved diagram as you mention . is my system also same as your improved one. ?

 

[Babadag]

It seems to me this one fits what I said "an improved diagram”, indeed.

However, these are actually two section of the same busbar.

This system permits to work on a one busbar -clean or repair insulators, potential transformer or else.

No circuit breaker can be substituted- all transformer or feeder circuit breaker will remain in circuit .

If both busbars are energized and coupler circuit breaker is kept close then the transfer from one busbar to another is realized by closing the disconnector connected with this busbar without any interruption.

An actual transfer bar facilitates use the coupler circuit breaker instead of anyone of the transformer or feeder circuit breaker. See[for instance]:

http://www.ece.umn.edu/class/ee5725/SubstationReliability.pdf