Part of our incoming voltage is 15KV and part is 138KV. We routinely move power to the pot lines according to what the market does. Two of our transformers are on the 138KV feed and three of them on the 15KV, two of the four Generators feed our 15KV for the plant, one feeds 138KV and the fourth is a split ownership feeding the 138KV to the grid and us.
We consume about 97 MW per pot line, 300 MW total when all three are running. Our Reversing Mill surges 15 MW when it starts and stops. Very large motor on that mill.
We do a few strange things with our power. Type 1 and Type 2 demand interruptions. If the midwest grid needs power due to a power plant going offline, we can dump a pot line for up to 1 hour and give 100 MW to the grid. We also do a thing called Modulation, basically our tap changers on the transformers are controlled from the grid operators. We vary our amperage from 125,000 amps to 132,000 amps to help distribute load on the grid. Some pretty cool stuff with power around our plant.
And that panel pictured above, had one dance itself right off the wall with the arc flash. That was a 15KV substation panel.

AND just now as I wuz trying to click on this thread, I had a power outage that lasted maybe 1/4 of a second, just enuff to force computer into a reboot....and of course wife goes to change channel on the TV and finger on rong button, so it's into a reboot also......so TWO reboots in same room, cause two separate causes......kan't win......

effing arthurongus acting up this AM, for no reason, so 1000 mg of ibuprofen....:issues:

That is a recloser doing it's job.

When there's a fault it cuts power then recloses the circuit when the fault clears.

My company makes those.

I imagine FERC compliance is a pretty big deal for you?

GOOD, so the thing senses when there is an overload, could be a bad xfmr or maybe a down wire, so how does it know when the circuit is clean enough to reclose the connection?? :dance::confused5:

Reclosers are only used on overhead lines, because they frequently have temporary faults, like a tree branch or animal or something.

It will try 3 times to reclose and if the fault still exists it will stay in the open position.

Yes for our power plant. Whole bunch of regulations. We have our own power plant plus 4 tie lines feeding into/out of the plant. Vectren has a station next to us, Culley, which could feed one of the pot lines if needed. I've actually had to do the switching over to the Pot Line interchange when our power plant had issues with a Breaker for two of our pot lines. Christmas day last year, 3 hours of downtime on two of the lines. If we touch on 1 hour we are scrambling, two we are very nervous it might not recover. At 3 hours we are pretty sure we will loose at least 75 of the 150 pots. We came out of it not loosing a single pot.

Our rectifier road is pretty impressive with all the main regulating transformers, then the individual skid transformers and phase shift transformers. Line 3 has 1 Main and 10 rectifier transformers, Line 4 and 5 each have 1 main and 6 rectifier transformers. Each rectifier transformer feeds two skids. Each rectifier transformer can provide approximately 14KVA to the skids. The lines are 700VDC at 132,000 each.
Lots of air switches, pringles and Gas switches. For the rest of the plant there is a multitude of substations my Maintenance department is responsible for maintenance on. We keep two power engineers busy on our side plus the one at the power plant.

You can google Alcoa Warrick Operations and see the size of the plant.

Never heard the term before.....rectifier is easy......just a one way valve for current flow, when presented with current/voltage......so is the term transformer, changes the voltage/current levels between primary and secondary......but overall power is same on output and input, minus some small losses in the unit itself...it gets warm.....

but what is the relationship between those two distinct devices in that combo you mentioned there.......and WHY?? and the way you talked of it, sounds like those rectumflyers are VERY manly in their forward conduction in amps.....so what how/what are they made of???

I visited a few power plants in the early 80's when doing security work, and got a cooks tour of the joints, but never heard that what you speaking of.....

:confused5:

The transformer steps down the voltage from 15KV or 138KV to allow the rectifier (Diode Banks) to rectify the voltage from AC to 700 VDC for use in the pot lines. Each pot uses maximum of 5 volts, typically around 4.6 volts we just say 5) 150 pots x 4.6 = 700VDC with 132,000 amps flowing thru the open aluminum bus work. All the floors are ungrounded. You can walk up and touch the bus with no effect. Very high magnetism around the lines. We have to have special mobile equipment to drive over the bus in between the pots. Each room has 35 pots south and 40 pots north (75 per room). The power flows up one room and back to the rectifier in the other room. One skid at the rectifier is positive the other negative. Some pretty cool stuff with electricity.
The pots themselves are like a great big battery when you pull the main power off the line. They hold a couple volts apiece.

OK, what you calling a POT, is short for potentiometer.....or volume control in typical speak......to MY way of thought.... so just what to those pots feed and how are they adjusted?? sorry to be a PITA, but an ancient tech head just wants/NEEDS to get his brain around something unknown.....

In the Smelting terminology a Pot is the object which holds the Cathode blocks, Anode Blocks, Alumina, Coke and Flouride to create a Chemical reaction to produce Aluminum. The pot holds all the material and by passing electricity thru the cathode blocks and Anode Blocks creates a chemical reaction to produce the Aluminum.
This will explain it a little better.

https://en.wikipedia.org/wiki/Aluminium_smelting