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Author Topic: Windmill power cable  (Read 1873 times)

Offline sawdstmakr

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Windmill power cable
« on: February 08, 2018, 11:02:38 am »
My sister in law lives on a mountain in Colorado and has a tall tower that she can use for a windmill. The problem is it is 1000 feet or more from her house. How far away can you transmit the wild AC.
Jim

Offline jvalentour

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Re: Windmill power cable
« Reply #1 on: February 08, 2018, 11:13:03 am »
I'm guessing pretty far since our power grid uses AC not DC.
That's why Edison lost out on the money on the beginning of the the use of industrial power grid because he promoted DC.

Offline sawdstmakr

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Re: Windmill power cable
« Reply #2 on: February 08, 2018, 11:29:44 am »
I guess the real question is what size cable would be required? Would the size be in reasonable.
Jim

Offline Michael Bush

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Re: Windmill power cable
« Reply #3 on: February 08, 2018, 01:39:45 pm »
What does she want to power?  Lights?  Refrigerator?  An entire modern electric house?
Chart:
Gauge: amps
10 gauge: 30 amps
  8 gauge: 45 amps
  6 gauge: 60 amps
  4 gauge: 80 amps
  2 gauge: 100 amps
  1/0 (one aught) gauge: 150 amps
  2/0 (double aught) gauge: 200 amps

In theory distance does matter, but with 110v ac 1000 feet shouldn't matter too much.  220v ac will travel better.

Here are charts:
https://en.wikipedia.org/wiki/American_wire_gauge
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Offline sawdstmakr

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Re: Windmill power cable
« Reply #4 on: February 08, 2018, 02:07:48 pm »
Thanks Michael. The reason I am asking is that, like a 10 gauge wire can only handle 80% of 30 amps for about 125 feet. Beyond that the resistance is too high. I will recheck this chart and see if it accounts for distance.
Jim

Offline Michael Bush

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Re: Windmill power cable
« Reply #5 on: February 08, 2018, 03:09:25 pm »
The formula for resistance is in the link, but I guess you can look for a direct chart of distances perhaps...  220v will fall off less for the same distance.
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Offline Acebird

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Re: Windmill power cable
« Reply #6 on: February 08, 2018, 03:40:52 pm »
What voltage does the wind mill generate?  I think a thousand ft is a long way to go.  It may make sense to boost the voltage with a transformer and then step it down where you want to use it.  The transformers are an added cost but it is better then loosing power constantly.  Also low voltage due to wire resistance is bad for motors.
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Offline paus

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Re: Windmill power cable
« Reply #7 on: February 08, 2018, 04:12:06 pm »
That distance you would lose power from line resistance.  When I did honest work we would measure the resistance of a spool of wire and we were always surprised.  Power lost can be calculated by Ohms law formula amps squared times the resistance, as you can see the power loss goes up exponentially as the current is squared.  You may want to consider a transformer on both ends, by stepping up the voltage The current is reduced.  You can often find surplus transformers that are just what you need.  The problem with this is the transmission voltage is higher and more of a hazard than 110 or 220 so safety should evaluated by a qualified electrician or preferably an engineer.  If practical I would suggest underground wire in conduit.

Offline sawdstmakr

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Re: Windmill power cable
« Reply #8 on: February 09, 2018, 12:23:10 am »
I went on google maps and found the tower, we think, and
Measured the distance to the house. Not certain but it looks like it is only about 500 feet.
This is much more reasonable distance. 2/00 would still cost about $1500 or more. Another problem is that this is mostly granite which makes trenching and boring out outrageous. I will probably design a pole line and go aerial. Drilling 4 pole holes is a lot cheaper even with the cost of the poles than boring on top of a mountain.
Still hoping to her from Divemaster as to what he thinks.
Jim

Offline Acebird

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Re: Windmill power cable
« Reply #9 on: February 09, 2018, 08:16:44 am »
I don't know why it would have to be buried if it is on your own land and from your own power source.  If it was in conduit and marked what is the danger of having it on top of the ground?
Brian Cardinal
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Offline sawdstmakr

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Re: Windmill power cable
« Reply #10 on: February 09, 2018, 09:35:02 am »
I don't know why it would have to be buried if it is on your own land and from your own power source.  If it was in conduit and marked what is the danger of having it on top of the ground?
That is a possibility Brian. The tower is not actually on her land but she does have rights to use it. Her previous owner built it. If she could it would be best to bury the cable.
Jim

Offline jvalentour

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Re: Windmill power cable
« Reply #11 on: February 09, 2018, 11:50:34 am »
A very good reason to bury is falling trees.  When the previous property owner installed my lines on poles tree growth was not a consideration.  Now it's a great concern.


Offline Acebird

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Re: Windmill power cable
« Reply #12 on: February 09, 2018, 02:17:32 pm »
I don't know why it would have to be buried if it is on your own land and from your own power source.  If it was in conduit and marked what is the danger of having it on top of the ground?
That is a possibility Brian. The tower is not actually on her land but she does have rights to use it. Her previous owner built it. If she could it would be best to bury the cable.
Jim

I think if I were going to do it I would put the hot wire overhead and lay the ground wire on the ground.
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Offline minz

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Re: Windmill power cable
« Reply #13 on: February 10, 2018, 12:39:37 am »
The size of the wire is for the amount of current. If you are only doing a small amount of current, small wire is ok. You step up the voltage to get more power through the wire (power is volts times amps you step up the voltage the current goes down proportionally). You have 240 Watts of generator at 240 volts, 1 amp, or 120 volts, 2 amps.
So you run the amount of current through the voltage drop calculator until you are not below 10%. Or just post the KVA of the generator (or nameplate). We will figure it out for you.
The smaller the wire will just throw away more power in the form of heat.
The advantage of AC over DC is that you can step up/down the voltage with a transformer. It is not that it goes further.
The advantage of DC over AC is that there is no impedance. We step up the voltage to 500,000 volts and then convert it to DC to send it from Bonneville dams up here to California and from the CA nuclear plants back this way when they have a surplus.
Now I am going to get into the weeds. If the voltage drop is too large you can look at a buck-boost transformer. Basically it is a 120volt to 12 or 12 volt transformer that you wire in series.
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Offline sawdstmakr

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Re: Windmill power cable
« Reply #14 on: February 10, 2018, 03:28:16 am »
Thanks for the feed back.
Minz,
I guess what I need to find out is how many watts the standard home windmill will produce.
I will research that. Their electric bill runs from 50 to $80 dollars.
Jim

Offline gww

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Re: Windmill power cable
« Reply #15 on: February 10, 2018, 10:52:21 am »
Saw
I built a sawmill and had lots of help from a forrestry forum and I put in solar and got lots of help frome some solar wind forums.  The two that I visited most was.
http://forum.solar-electric.com/

https://www.fieldlines.com/

I came here for help on bees.  I got help at all the places for what I was doing.

I did build two wind turbines but have them shorted out right now cause they take much more resources to control then just solar which can be shorted out and you don't have to create saftey nets to send extra power to. 
Good luck
gww

Offline Acebird

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Re: Windmill power cable
« Reply #16 on: February 10, 2018, 12:06:06 pm »
The advantage of DC over AC is that there is no impedance.
Now I am going to show my ignorance.  I thought impedance was similar to resistance where resistance is used for DC and impedance is used for AC.  And I thought the advantage of AC was that you only needed one wire per phase using and earth ground at each end to complete the circuit.
Brian Cardinal
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Offline sawdstmakr

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Re: Windmill power cable
« Reply #17 on: February 10, 2018, 12:53:12 pm »
Brian,
In using AC and D.C. You still need a return wire. One side is referenced to ground and if you look at a power pole you will usually see a ground wire coming down the pole. This wire is tied to the neutral side and is designed to keep the neutral wire at the same potential as the ground potential you are standing on.
Using ground as the return wire is possible if the ground resistance is very low but that is rarely ever found. In Florida sand, we have to use 3-8' ground rods to ensure the telephone cable shields and strands are kept at ground potential. Power lines use a ground rod at every pole in order to keep it referenced to ground.
The original telephone system only used one line and ground but it was very noisy.
Jim

Offline Acebird

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Re: Windmill power cable
« Reply #18 on: February 10, 2018, 01:04:01 pm »
The thing is Jim when you generate your own power there is no neutral tap.  The power company does that so you can have 110 and 220 available in your home.
Up here the water coming into the house is either copper or steel and goes for miles under the frost line.  So if your neighbor down the street had a wind mill he could share that power with you by using one wire and return would be the water pipe.
Brian Cardinal
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Offline sawdstmakr

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Re: Windmill power cable
« Reply #19 on: February 10, 2018, 02:21:44 pm »
Brian,
I agree. In that case the copper pipe is the return wire. I would not use Galvanized pipe as the return line due to resistance.
Jim