duresca bus duct

[royclh]

hello, has everyone come across this type of bus duct? any information i can get? This busduct has been proposed to an offshore wind farm main transformer rated at 150/33kV. HV primary connection we use gas insulated busbar and LV connection is the duresca bus duct. I'm wondering what are the advantages of using duresca bus duct than cables?

Your info will be greatly appreciated. Many thanks in advance.

 

[slavag]

Hi.
It's a really good product, something special.
I don't work for them .
Advantages, you don't need few condactors per phase, special isolation. I know projects with this bus duct 20 years in operation w/o faults.

Good choice.

Best Regards.
Slava

 

[Marmite]

What is the transformer capacity?
What is the distance between the transformer and 33kV switchgear?

Regards
Marmite

 

[7anoter4]

Duresca is a solid cable with a paper insulation epoxy impregnated. It is less flexible but may be bended with less radius than similar cable using a prefabricated bend.
The water tree and the partial discharge properties are better than in a XLPE insulated cable. But there are many appurtenances supplied only by MGC as terminating, bends, connectors and other. As the system is rigid even is very well insulated and protected needs a clear routing and use of a usual cable tray is almost impossible. The wall penetration is also a MCG piece. But it is a system good for long time. Cable is more flexible there are many manufacturers for accessories and may be laid easy. See more information here:

http://www.mgc.ch/PDF/duresca.pdf

 

[jjmoab]

We installed DURESCA bus duct for our new cogeneration planta last year. Step up transformer is 65 MVA 11,5 kV generator side.

I´ll try to find some information ant post it.

 

[royclh]

thank you for sending me all the information. I really appreciate that. the transformer capacity is around 200MVA. Distance to the hv switchgear is approx. 20m, and distance to lv switchgear is approx. 30m. Can distance also be the factor to determine the choice between cable and busduct? I used to think busduct is preferred if one is to carry high current ~ 4000A or high. please correct me if i'm wrong. thanks,

 

[xxjohnh]

Exxon used DURESCA in their Singapore plant about 10 years ago, for 66/33Kv. It is an alternate to ISO PHASE bus at higher voltages. Also it can be installed in trenches. Not widely used. They have quite a good website.

 

[ScottyUK]

Air-insulated isolated phase bus duct normally requires a slight pressurisation from a clean source of air. In most instances this will be from the plant air or instrument air systems, but offshore it would likely be impractical to provide this because of the heavily salt-laden air and the additional maintenance required for the compressor and dryer plant. The Duresca product provides a nice solution to the problem.


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If we learn from our mistakes I'm getting a great education!

 

[xxjohnh]

Duresca has not outer casing like Isophase bus. It is solid single phase bus insulated with a thick solid insulation. Every thing is factory built and the section are bolted together then insulated.It goes up to 230Kv.

 

[7anoter4]

For 4000 A load you need at least 6 cables of 2000 MCM [1000 sqr.mm] copper per phase [18 cables total].For only 30 m distance Duresca it is the better solution. You need to support well the busbars mainly in order to withstand short-circuit current force but also its own dead weight. The space around has to be well ventilated to evacuate about 1.8 kW per meter [for all 3 phases] losses. I think the outer sheath –even it is corrugated and nylon coated-may be very hot.
MGC has an original design calculation way [you may order the design with the package, I suppose].

 

[ghostbuster7]

Duresca product is essentially manufactured similar to high voltage transformer bushings with multilayers of foil capacitive grading.
When going from inside a building to outside flexible braided coupling joints are used at the ends to allow for expansion and contraction.
The product has been around for at least 30 years and primarily spec'd in Europe.