Substation Design 5

[SauravWest]

Dear sirs,

I want to design an intermediate substation which can transmit around 555 MVA.
Incoming double circuit 220 kV lines bring power. And outgoing 132 kV double ciruit lines take power.

1. Will single breaker double bus system be sufficient?
2. For high power, we use single phase autotf, so 6*92.5 MVA will suffice I think.
3. If Gas insulated substation, how equipment arrangements continue? I think it starts from lightning arrester, CVT and then?
4. PT can be kept one for each bus?

Please reply,

Sincerely,

 

[Mbrooke]

What? No 12 position main and transfer? That is a shame.

https://files.engineering.com/getfi...cc-4539-a17e-61bb209ae3a3&file=SAMASTIPUR.pdf

Sadly NERC and other reliability standards are forcing multi breaker designs. Even series breaker indirectly in some cases.

But if you ever had the privilege (freedom) of doing it as you like, nothing beats single breaker designs like these >>

David, I highly encourage you do print these out and send them to everyone in your company just as seeds of inspiration.

 

[davidbeach]

Those are ridiculous. Breakers need maintenance and trip checks much more often than buses need taken out of service. I think you entirely missed bacon's comment about the nightmare of trying to provide proper bus protection for something like that. No, I think we've got a much better approach.

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

 

[bacon4life]

kartracer087/Mbrooke- Sorry, I now see kartracer087 was referring to Mbrooke's diagram posted at 19 Apr 21 13:37 rather than Mbrooke's photo posted at 20 Apr 21 10:37.

 

[Mbrooke]

@David: I agree, but with modern SF6, maintenance is much less needed. While buses are taken out of service less often, the impacts of having to take multiple lines out of service for a once in 15-40 year event are much greater than singe lines in rotation during low load periods during the season.


With 3 487Bs its not much of a nightmare. Just wire 87 open/close into the 487s and the internal logic does the rest. Even comes with a check zone to keep stability if any 87 contact malfunction took place. The 487 also does breaker failure.

Or an even simpler approach (as done in some countries) is to either go single zone or skip BB protection altogether.

@Bacon4Life- understood and its alright.

 

[davidbeach]

So there may be some obscure alternate universe in which that design makes sense. Probably also requires live tank breakers with all the CTs on one side and suboptimal bus protection. Those that live in that alternate universe are welcome to it. I can see absolutely no advantage to a bad design over the well proven BAAH layout. I’m done.

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

 

[Mbrooke]

Alternate universe would be 85% of the globe, live tank breakers, but I do hear you David. BAAH is ideal in more ways than one and that is also my personal opinion. No dispute there.