Volatge level Selection

[hamna23]

We have a few motor driven loads i.e. pumps and compressors, rated from 350KW to 800KW; @ 3000 RPM that are being designed for our fertilizer plant. The volatge level that we are receiving is at 11KV.

Now my question is, what is the most appropriate voltage leve in terms of cost, supply, availability and future maintenance?

 

[itsmoked]

How about you provide a list shopping list of your expected loads. The more info the better the answers.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

I would start by enquiring of the utility what voltages they are willing to provide.
Even if you are providing your own transformers there are a lot of advantages to using the same voltages as are commonly supplied by the utility.
In an emergency you may be able to borrow or rent a transformer from the utility. If you increase capacity at a later date, your original transformers will be easier to resell.
You probably want the highest low voltage that is common locally. That may be 400V, 480V, 600V or your local voltage.
respectfully

 

[ScottyUK]

11kV and 3000rpm makes me wonder if you are in the UK. If so I would suggest 3.3kV for motors in this size range because the lifetime costs will almost certainly work out lower than either 415V or 11kV. The 415V option would require very heavy switchgear and be expensive in terms of cabling, plus volt-drop would be troublesome for long runs. The 11kV option is heading toward semi-custom motors (expensive and spares are on a very long leadtime) and the choice of manufacturers and repairers is much smaller than for 3.3kV machines. 3.3kV is much less challenging for the maintenance guys (cable is still the familiar XLPE type) and PD is virtually unheard of at 3.3kV.


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Sometimes I only open my mouth to swap feet...

 

[waross]

If you are in the UK, I will defer to ScottyUK's local knowledge.
respectfully

 

[anandmoh]

In India any motor capacity upto 200kW is preferred to be run on 3-phase 0.415kV ,beyond which it is techno economic to run on 3.3/6.6/11kV.If you insist to run on 0.415kV,for capacities greater than 200kW,other options like dual drives can be thought of.Again it is a matter of choice depending on the availability/non availability of a particular voltage level in your premises.

 

[VxA]

If you are in the US or Canada, I would have been tempted to recommend 4.16kV. Waross has an excellent point about it being a good idea to use voltage levels that are in common use in your area. I'm guessing you are not in the US or Canada as you stated the motor ratings in kW not hp (which is more common to see in North America). Also, I'm not familiar with distribution voltages of 11kV...