Idle 15kV transformer uses how much power?

My brother recently bought an old Ethan Allen manufacturing plant in Erie,PA. to convert into industrial condos. This facility has an incoming power line of 15000 volts wired to on site transformers. I have no idea how many amps of what voltage the transformers are capable of, but he's getting whopping power bills from the utility. The utility swears the bills are for current usage only. No legacy issues, nothing other than power consumption. The plant is currently empty, and the only thing running is an air compressor who's sole mission is to keep the sprinkler system pressurized. The power bill for that month was $750. Add a small baseboard heating unit turned up just high enough to keep the water pipes in a small office area from freezing, and the bill jumped to $2000. Is there any way this is realistic? Could the transformer be using that much power even though it's idle 90% of the time?

Thanks,
t2r

Check the bill for the method used for measuring consumption and the cost per unit if it applies, also is there a base service supply cost?
Minder.

With ONLY a magnetizing current load from large transformers, his actual power bill might be low, BUT the bad power factor penalty will eat him up, maybe.

A good transformer will have a large magnetizing inductance, and will draw a few percent of full load current.

BUT the inductance will draw that at almost a 90 degree phase shift, so the power factor may be really stinky, down around 0.2 or so possibly. I actually don't know.

In any case, ALL the power you draw at that sort of power factor will be billed at the penalty rate. Therefore, a couple kW of heater will be billed at some horrible multiple of the real cost per kWh.

There are about 720 hours in a month. if you are penalized 5x on a 10 cent per kWh base cost, then a couple of kW continuous load would add up to around $750. It would not be that unusual for some large transformers to pull power like that. it might be more.

Add some kWh for keeping an area warm in a cold winter, and multiply by the low PF penalty, and you just might get on up to 2 grand.

I have no idea what the base cost or penalty is there, so the numbers may not add up as I say, but you should be able to look at the bill and determine the base kWh and the penalty.

There is sometimes a benefit to not having power officially "turned off", but there is also a benefit to not pulling a penalty load every month....... Some of the transformers might be unnecessary, and turning them off might not constitute official cutoff of power.

Hold on guys. This was a manufacturing plant.

It probably has three phase power feeding it.

Please inspect the METER that the utility is using. If it is a
"peak demand meter" then please report this back because
it would explain your power bills.

1) photograph the meter.

3) read the power bill.

If you see anything that says "peak demand charge" then you will
have your explaination right there.

Jim

jim rozen said:

Hold on guys. This was a manufacturing plant.

It probably has three phase power feeding it.

Please inspect the METER that the utility is using. If it is a
"peak demand meter" then please report this back because
it would explain your power bills.

1) photograph the meter.

3) read the power bill.

If you see anything that says "peak demand charge" then you will
have your explaination right there.

Jim

Click to expand...

Jim, I am ASSUMING THIS OBVIOUSLY HAS 3PHASE.

But the peak demand won't exist...... continuous magnetizing current, or a few heaters do not equal big peak demand.

I figure the meter is reading POWER FACTOR, and the POWER FACTOR is rotten with the magnetizing current. The penalty charge, if there is one, which is likely, could account for it.

I agree with JST on the power factor, the plant could have a very large total transformer capacity, if the plant is large enough to have distributed 15Kv transformers then the capacity of these could run into several MVA, both magnetising current (if current is billed) and hysteresis loss will be contributing to the bill. Your brother needs to walk around and find the transformers and note their Kva rating and if it is safe to do so, feel if they are warm. Also call the power company and ask them, the power company will know about distribution transformers better than anybody other than the manufacturer.

"....and the only thing running is an air compressor who's sole mission is to keep the sprinkler system pressurized...."

There's the demand that is being billed as peak demand. The compressor is
effectively running ALL THE TIME. Also see the point where he comments that,
when the 'small heater' was turned on, the bill really went through the roof.

I maintain, the problem is one of billing method. If he can get rid of the
peak demand meter (good luck on that) it'll become much more reasonable.

At any rate I never argue about those things which can be tested and
proved, or disproved. The magnetization current (reactive) for the
transformers *can* be measured. He needs to get an electrician to do this,
and also an accountant to explain his power bill to him. My vote, the
second will be much more important, than the first.

Just a guess.

Jim

Thanks for the replies,all!

I've forwarded them to my brother along with a request for photos of the meter and specs on the transformers. I'll keep you posted.

t2r

Do you mean the union city location ?

http://maps.google.com/maps?hl=en&ie=UTF8&ll=41.894994,-79.84764&spn=0.00248,0.003197&t=h&z=18

It's the only one I know of, and is pretty large.

There are/where kilns in the back (to the right)
and somehow they made heat, and steam.


Seeing how they were one of the largest plants/demands
in union city, I could see how the electric company
gets' excited when you draw any amount of current.