Paralleing Switchgear Size?

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anbm

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If we have (4) E.G. each at 1,500kW, 408V/3PH and these E.G.s feed a paralelling switchgear. Based on total E.G. size, we would need a 12,000A paralleling switchgear @ 480V/3PH.

I will check Square-D, Asco as other manufacturers, however, I am wondering if there are any manufacturers make this such gear size?
 
We build those types of lineups and can do it with any manufacturer (Well, almost any) you would like, can be done with remanufactured switchgear to save money and reduce delivery times from new stuff from the OEM. Not a problem for us at all.
 
anbm said:
If we have (4) E.G. each at 1,500kW, 408V/3PH and these E.G.s feed a paralelling switchgear. Based on total E.G. size, we would need a 12,000A paralleling switchgear @ 480V/3PH.

I will check Square-D, Asco as other manufacturers, however, I am wondering if there are any manufacturers make this such gear size?
Click to expand...

I came out with much less that 12000 amps. Check it again.
 
(5) 2MW's @ 480V on a 10kA Par SWGR bus is being installed for me over the next month or two.
Check your math. Also consider that there will be some load flow to consider, as not every electron will flow through every piece of horizontal copper.
 
Here is the calculation:

(4) E.G @ 1,500kW / each = 6,000kW total.

Assume: 0.8 pf

6,000kW x 1.25 = 7,500kVA

At 480V/3PH:

7,500kVA / (1.732 x 480) = 9,021 Amp

Switchgear size = 9,021 X 125% = 11,277 Amp.

So should we use: 12,000A switchgear if they can custom one?
 
You could get a 12,000A custom SWGR, but consider whether it is worth it. Think of the electrons and where they are going (load flow).
"IN" from Gen#1 and before if joins up with the electrons from Gens 2-4, it will peal off and go to a load through a distribution breaker nearby.
Also, do you suspect that the loads will be drawing a 0.8 power factor? In the buildings I design, the facilities techs get to the kW limit of the gens way before they get to the kVA limit. So the current is less than your calculation.
 
anbm said:
Here is the calculation:

(4) E.G @ 1,500kW / each = 6,000kW total.

Assume: 0.8 pf

6,000kW x 1.25 = 7,500kVA

At 480V/3PH:

7,500kVA / (1.732 x 480) = 9,021 Amp

Switchgear size = 9,021 X 125% = 11,277 Amp.

So should we use: 12,000A switchgear if they can custom one?
Click to expand...

You have used the 1.25 multipler twice. I do not think you need to use it at all. If you do, once is enough.
 
bob said:
You have used the 1.25 multipler twice. I do not think you need to use it at all. If you do, once is enough.
Click to expand...


The first one is to convert from kW to kVA with 0.8 pf

The second one is to comply with NEC for sizing feeder.
 
im not sure but isnt the correct calculation

1500kw x 1000= 1,500,000watts

1,500,000watts x 4 = 6,000,000watts

6,000,000watts/830= 7,229 amps

7,229 amps x 1.25=9,037amps
 
shaw0486 said:
im not sure but isnt the correct calculation

1500kw x 1000= 1,500,000watts

1,500,000watts x 4 = 6,000,000watts

6,000,000watts/830= 7,229 amps

7,229 amps x 1.25=9,037amps
Click to expand...

Why did you convert 6,000kW to Amp without convert it to VA first?
Do you assume power factor equal 1 ?
 
shaw0486 said:
why how do you know what the power factor actually is
Click to expand...

Right way is verifying it with actual motor manufacturer. For calculation purpose, 0.8 is a good number to go by. And I am sure it is not 1 (unity).
 
anbm said:
If we have (4) E.G. each at 1,500kW, 408V/3PH and these E.G.s feed a paralelling switchgear. Based on total E.G. size, we would need a 12,000A paralleling switchgear @ 480V/3PH.

I will check Square-D, Asco as other manufacturers, however, I am wondering if there are any manufacturers make this such gear size?
Click to expand...

Look at physical configuration and see if there is ANY possibility that 12000A would flow through any segment of the busswork.
 
For that range of amps i would suggest a stepup transformer.

We did this in a large dairy farm which has 22 synchronised generators of 380 volts 1275 kw each.

The output of generator is stepped up to 13.8kv thus reducing the cable size and transmission losses.

It is then stepped down to 380 volts at remote user points.

cheers.
 
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