Construction Power for Substation

Well, it all depends on the design of the substation. You might need low-voltage for transformer cooling fans. Any telemetry equipment will probably require low-voltage to feed their power supplies. Some substations require perimeter surveillance equipment to deter theft and foolish suicides. Motors for remote switching will probably need low-voltage. You might even need outdoor lighting. You probably won't need to heat a hot tub but if the customer wants one...

Redfred, I think the OP is talking about (temporary) construction power, not accessory power for misc loads in the substation.

To the OP: You need to find out what equipment your installers / constructors of the substation expect to use. Besides tools and installation equipment, they may have a construction trailer or other shelter that needs lights, heat, power for computer, etc. You can't just guess. However, based on projects I have dealt with, I'd say 50kVA is plenty for what is likely to come up unless it is a very large substation with multiple constructors and their facilities. But your best bet is to talk to the various constructors and get their power needs from them.

If this is electric power for construction then I would expect the construction contractors will be using their own generators instead of tapping into the high voltage grid to make a substation. I also wonder what kind of oil filtration needs to be performed to construct a substation. A simple funnel, filter paper, two buckets and gravity can filter oil, albeit very slowly.

That's interesting to know, thanks.

Still, this is a temporary task. I would expect whoever is contracted to perform this commisioning work will have their own equipment requirements covered in one of two ways. They will bring all that they need or specify in their contract that which must be provided.

If you're building a POWER substation, wouldn't you already have POWER for the construction phase?

Electrical Substation Design, Modification & Construction

Your Guide to Electrical Substation Construction - NU Transmission

<...This makes 25.12 kVA load....> Actually, it makes 21kVA.

As to <...ideas...>, contact the vendors of the oil filtration plant and get a <...so sure...> figure!

No, it's 7kW for the lighting + oil filtration plant, 14kVA for the welders. It would be 21kVA if the lighting + oil filtration plant had PF 1. Incandescent lighting has PF 1, but fluorescent and LEDs are lower. We don't know what lighting the OP has. The oil filtration plant is likely to be less than 1.

Whatever. The OP still needs to the oil filtration plant vendor, and discuss.

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I have an idea.. go back to school and learn how to calculate loads!

If you can't work out a simple load, and have your considered 'diversity', then you are in the wrong job!

Harsh? Yes!