Co-Generation type Switchgear

[bipinsa]

All,

I am looking for technical data, typical vendors, who can or actually have used 15kv, 6000A, 60KA switchgear. I was able to find one at PACS industries, can anyone share me their experience?

Thanks,
Bpn

 

[rbulsara]

6000A, 60 kA (symm)would be very unusual at 15 kV, if at all available.

2000A, 21 kA symm. (500 MVA) is more common. But then I haven't seen it all.

Rafiq Bulsara

http://www.srengineersct.com

 

[DTR2011]

You can find generator breakers at this level. A whole lineup of switchgear...I've seen maybe 3000A.

What is your application?

 

[davidbeach]

I've pondered this one all day and keep coming back to my original thought - 6000A, 60kA is just an indication of someone having picked the wrong voltage. If this is multiple machines, you need to parallel them at a higher voltage level. If it's one machine it is probably at too low a voltage, but even so, it should have a single generator breaker at most, but I'd unit connect it and have the breaker on the high side of the transformer.

 

[ScottyUK]

ABB, Siemens, GE all have a generator breaker in their lineup.

60kA at 15kV is one of the trade-offs generator manufacturers have to make. It's not a particularly high fault level by the standards of a generator bus. As David has said, the alternatives are insulate the stator to a higher level,or to run the machine close-coupled to the GSU transformer and synchronise at the HV breaker. The former solution makes the machine considerably larger and more expensive because of the amount of active material lost and replaced by insulation. The latter, if used in a multi-unit generating station, may increase the number of HV breakers required, which are even more expensive than the LV generator bus breakers.

I'll see if I can find a couple of links to gen breakers later on. The ratings are quite impressive.




----------------------------------

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

 

[Zogzog]

I have worked with PACS on some similar projects, they are very goood at this sort of application.

 

[FunFacts]

"I am looking for technical data, typical vendors, who can or actually have used 15kv, 6000A, 60KA switchgear. I was able to find one at PACS industries, can anyone share me their experience?"

At this voltage I've seen 6000A switchgear, 63kA, arc-resistance to boot made by Powell switchgear. I am sure there are others.

 

[ScottyUK]

Powell are among the vendors who have a distribution-class breaker which doesn't have adequate breaking capability at the X/R conditions typically found near to a large generator infeed. A distribution breaker used in such a situation would be a dangerous mis-application of the equipment: they simply aren't designed for such severe duty - it's not intended as a dig at Powell particularly.

You need to look at the assymmetry, the associated large DC component and the long time to first current zero crossing. Generator breakers are a totally different animal to a distribution breaker, often comprising a bank of single-pole breakers.

Have a look at ABB's HECS range for a typical GCB:

http://www.abb.co.uk/product/us/9AAC30200091.aspx

----------------------------------

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

 

[FunFacts]

ScottyUK, thank you for the info and link -- rather fascinating. Are these GCB designed per IEEE C37.013 and C37.013a?

 

[ScottyUK]

Yes, I'm pretty sure the HECS range is designed to C37.013. If I remember correctly C37.13A is for 'smaller' breakers for machines below about 100MW or so - I'm at home and haven't got the standards to hand to check.

For the OP, here's a Siemens product which looks like a great fit for your application. The HECS is a little on the large side.

http://www.energy.siemens.com/hq/po...91021-Za-Generatorschalter 3AH37_3AH38_en.pdf

----------------------------------

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

 

[rcw retired EE]

PACs can provide the generator breaker in typical metal clad switchgear but I think it is pushing their ratings.

Use isophase bus to interconnect the generator, a dedicated generator breaker, and a GSU transformer. You can also direct tap the GSU isophase to feed the plant Auxiliary transformer for medimum voltage (6.6 kV, 4.16 kV or??). This is the design that the majority of combined cycle or cogeneration plants use.

Generator breakers can be supplied by ABB, Areva (now Alstom?), Hitachi, Siemens, and another Asian supplier that I can't recall right now (Hyundai, Toshiba?). All build to the ANSI or IEC standard. Pricing is very competetive.

This gear is not draw out. Everyhting is fixed in place and can be equipeed with built in disconnect switches and grounding switches.