300 HP electric Motor 4160 Volts (Not VFD) need help sizing transformer and related components.

K

KranK

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Searles Valley
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Project Engineer
Some people argue that, "Magic doesn't exist, and that Magic isn't real."

To those I strongly disagree, and you would too if you could see electricity through my eyes. Given my minimal understanding of this amazing craft, through my eyes I see colorful bright lights, and still get excited when I see objects that are magically set into motion. Whereas, through the eyes of the, "masters of the craft" known to be "Well-Grounded" in their understanding of electricity; consider my understanding to be quite dangerous.

Here is where I would greatly appreciate any one who is willing to help me.

I have been tasked with drawing up the plans for a booster pump station. I have the mechanical end of figured out pretty good its the electric part that has me a bit puzzled. The motor that I need to power is 300hp 4160 Volt. The location is outside on a concrete pad next to the power poles that we plan to use to supply the power. This configuration is NON VFD.

What I would like help with is, properly identifying the electrical components on my plans so I don't look as incompetent as I did at the beginning of this thread.

***FYI This project is in the early stages of development, and the purpose of my work is to provide ball park information for budgeting. Although these won't be the, "licensed PE stamped Design," I would like to be as accurate as possible as they will be used as a main reference, for the final design by a licensed engineer...hopefully.
 
Is there anything going in there (lights, telemetry, control system, "convenience" outlets, etc)? That would indicate a need for lower voltages (e.g. 208/120v). It's conceivable that you take 3-phase 4160 from the power company (PoCo) thorough the service equipment into the motor controller and also into a step-down transformer and low-voltage panel for the rest. Each of those has assorted over-current protection.

Everything will need to be rated for use in the Great Outdoors. Doesn't look like you're near the ocean, so no salt water exposure and stainless-steel enclosures, but OTOH deserts can get might hot in the summer so you'll have to take that and the winter cold into account.

Oh, and the local PoCo will have their own requirements for connection, you can see PG&E's at https://www.pge.com/en/account/service-requests/building-and-renovation/greenbook-manual-online.html but they all have one.

(There may be a packaged "pump controller" that will do most of the work, that's above my pay grade.)

ETA- are you sure you want the pump on 4160v and not 480v? Packaged 480v pump controllers are out there and probably more common than MV ones.
 
PG&E's green book table on motor & service sizes pretty much says "Single motor over 100HP? Call us.". (For planning, I'd assume using a soft-start if you're not using a VFD, especially if you're out in the weeds at the end of a miles long line from the nearest substation.)
 
Depends on how you are deriving your 4160V. Assuming 12.47kV primary from the utility, you will need a 12.47kV service disconnect with fuses for the transformer primary, a transformer with a kVA roughly 3x the motor HP (rule-of-thumb), then a 4160V starter off of the secondary of that transformer, assuming nothing else at the site. If there is other stuff, then get a "Station Service Transformer" built into your 4160V gear, with a small LV transformer and panelboard for those other loads. If the utility is giving you 4160V from THEIR transformer, then you can just get a 5kV Class service entrance listed lineup with the Station Service setup, feeding the 4160V starter.

But as others have said, I wouldn't be assuming that you can start a 300HP motor Across-the-line even if it is 4kV...
 
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