Highest rating for 11kV switchboard.

[PrebenJakobsen]

Hi-
I am looking for a switchboard produced after IEC62271-200 for an 50Hz - 11kV offshore installation.
General limit for most vendors seem to be 4000A nominal and 50/125kA short-circuit.

Does anyone know a vendor with higher values on one or both parameters which has a reference list for offshore projects?

Best regards
Preben Jakobsen

 

[ShooterBoter]

Schneider-Electrics PIX-H switchgear is one. Don't know if they have any references to offshore, you'll have to ask Schneider.

 

[ScottyUK]

I don't think PIX-H exceeds the OP's stated values, does it? The only MV products I'm aware of which exceed those ratings aren't distribution-class breakers, they're for generator duty and have thermal ratings of 12kA or more, with fault withstand of 72/200kA or more. Siemens VB1 / HB1 series are typical of the type.

What's the application? You're looking for unusually high ratings - is it time to consider a jump to the next voltage band, or splitting the board into two? In an offshore application with on-board generation be very careful if you're using distribution-class VCBs in generator applications because they can't handle the severe breaking conditions caused by the high X/R ratio and long time to first current zero. The interruptors burn away due to the persistent arc, then fail.

 

[PrebenJakobsen]

Hi ScottyUK
I am in the early phase of a platform design and is on the limit of the 76 MVA that is a result of 11 kV and 4000 A. And when the project develops the load normally increases.
I would like to keep 11 kV and connect the generators directly to the main SWBD and I also would like to have all generators on same SWBD as it gives me flexibility: In the early phase when the load is high it will be easyer to maintain generators and in the later phase when load might decrease I am able to run only the required no. of generators.
I am aware that i can't assume the standard T=45ms and that I can't utilize the full rating of the SWBDs. In the current design i have included Is limmiters.

Right now I have a compact and light design which is important offshore. If i know it is possible to have 5000A it gives me pease in mind.
Datasheets for PIX-H gives that value (with fan cooling).

Best regards
Preben Jakobsen

 

[ScottyUK]

Siemens 8DA10 / 8DB10 range has a 5000A thermal rating but falls a little short on the fault rating - 40kA / 3sec. It's a gas-insulated bus so it should survive the offshore environment well, and being GIS it is very compact.

I admit that I'm slightly biased against some of the old Areva designs - which now a Schneider badge - because the quality control hasn't always been as good as it could be. I don't have specific experience of the PIX range, so it might be better than the stuff I have worked with.

 

[ShooterBoter]

Not that I advocate the Schneider switchgear, but it does exceed current rating, it's up to 5000A.
Link

 

[ScottyUK]

Thanks ShooterBlooter, that option wasn't shown in my old Area data.