# high voltage single phase overhead lines



## Electric_Light (Apr 6, 2010)

I almost never see them, but when I was driving through middle of the booneys in agricultural area, I came across relatively tall wooden poles carrying two high voltage wires. 

What voltages do these typically carry? What do they serve? I guess large irrigation pumps and farm house machines are three phase, so I don't get it.


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## Big John (May 23, 2010)

How big were the insulators? I wonder if that was high-voltage DC transmission?

Otherwise, it does seem weird. :huh:

-John


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## Electric_Light (Apr 6, 2010)

I didn't look that closely. I think it was around Stayton/Aumsville, Ore. 

I wonder if its the HVDC intertie that connects Sylmar converter station in Los Angeles and Celilo converter station in The Dalles, OR

Edit: nah, it couldn't be. The DC intertie is too far east to be there.
http://www.bpa.gov/corporate/pubs/fact_sheets/05fs/fs1005b.pdf


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## sucocoop (Jun 23, 2010)

Our coop here in Ks has 69 kv transmission, but never is it carried through a single phase. I also know a lot larger transmission carried through our area, yet again never single phase. Our single phase distribution carries 7200 volts from phase to ground and 12470 from phase to phase. We run a wye system with a neutral, but I do know there are some delta systems still existing out there. Not sure if that one could be or not. Could you tell what size wire it was?


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## Electric_Light (Apr 6, 2010)

No, I only saw them briefly from the backseat of a car. It was going through middle of farms though. I wouldn't be surprised if they're disproportionately high for their voltage just to avoid getting tangled with farm equipment.


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## sucocoop (Jun 23, 2010)

Thats most likely the case. We try to keep our neutral at about 20' when we build new. It's quite frequent so see sleeves on the neutral wire where a combine or tractor has hooked and broken it.


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## Electric_Light (Apr 6, 2010)

sucocoop said:


> Thats most likely the case. We try to keep our neutral at about 20' when we build new. It's quite frequent so see sleeves on the neutral wire where a combine or tractor has hooked and broken it.


In what situation do you use phase to phase 12470v single phase distribution? I'm guessing serving residential customers in middle of absolute nowhere where there is no need for three phase service. 

In the city, HV primary isn't readily accessible, underground wiring makes a grid of 480v 3phase primary.


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## sucocoop (Jun 23, 2010)

We have approximately 4300 customers and 2500 miles of line, so thats about 2 customers for every mile of line. Of course when we have a high density load, a three phase line is good to carry several residences, and when you throw a couple oil leases and an irrigation pump on there, three phases are needed to evenly distribute the load.


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## jw0445 (Oct 9, 2009)

If your looking at two wires and you see a pot and they are both above it then both lines have voltage and can have a number of different voltages. If one line is below the pot it's a neutral.


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## Electric_Light (Apr 6, 2010)

I looked up Wellington, KS on Google map for the heck of it.

It looks like a Farmville with the exception of city center


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## sucocoop (Jun 23, 2010)

:laughing:

You're exactly right! Pretty much all soybeans and corn right now. All the wheat I've seen has been cut.


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## Electric_Light (Apr 6, 2010)

I have corn growing in my office too, on Zynga FarmVille


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## vadimTFK (Jul 1, 2010)

Guys, my first post here...
We have one 800kV DC HV overhead line Donbass-Volgograd (Ukraine, ex-USSR)...still experimental


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## Electric_Light (Apr 6, 2010)

vadimTFK said:


> Guys, my first post here...
> We have one 800kV DC HV overhead line Donbass-Volgograd (Ukraine, ex-USSR)...still experimental


A power cooperative called Bonneville Power Administration here runs a 1,000kV (+/- 500kV config) intertie between Central OR and Southern CA.


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## Introyble (Jul 10, 2010)

Electric_Light said:


> A power cooperative called Bonneville Power Administration here runs a 1,000kV (+/- 500kV config) intertie between Central OR and Southern CA.


I was thinking this may be Open Delta, perhaps its a top secret experimental voltage?


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## Electric_Light (Apr 6, 2010)

Introyble said:


> I was thinking this may be Open Delta, perhaps its a top secret experimental voltage?


That one is actually DC, with some redundancy. It can operate with any two wires damaged (except with two "line" and "line" broken). It uses earth as the return path in that event


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## Obelixx (Oct 28, 2010)

*Single phase AC lines*

In Germany, Switzerland, Austria and some parts of Sweden and Norway, the federal railway companies have an own power grid as single phase AC of 16 2/3 Hz is used. Operation voltage is between 66 kV and 132 kV.

The matter is well described on
http://en.wikipedia.org/wiki/Traction_current_line
http://en.wikipedia.org/wiki/List_o...ification_in_Germany,_Austria_and_Switzerland
http://en.wikipedia.org/wiki/Electric_power_supply_system_of_railways_in_Norway
http://en.wikipedia.org/wiki/Electric_power_supply_system_of_railways_in_Sweden


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