Pole xformer connections

[mdshunk]

Here's a diagram, from the Ronk Blocker patent that sorta tickles me. Not so often you see electrical diagrams that include cows and hogs.

http://www.google.com/patents/pdf/S...AJ&output=pdf&sig=IkyxnDu9Ajo0viKzOgOvV76jKRU

 

[peter d]

Yeah, that's pretty neat. But I'm guessing the hog trough and the milker have to be bonded to that mystery box for it to eliminate the stray voltage?

 

[mdshunk]

Yeah, that's pretty neat. But I'm guessing the hog trough and the milker have to be bonded to that mystery box for it to eliminate the stray voltage?

Well, they sorta are, by proxy. The "mystery box" is detail 21 in that drawing, just beow the pole top transformer. You can click on the link below the picture to read the patent over. It's pretty interesting reading, actually.

 

[loren]

Five wire systems would keep neutrals neutral and grounds ground.
I am not a IEEE member but there standard for computer feeders is 2.4 volts neutral to ground. Strangely enough it was passed in Las Vegas the same week the Pentium 4 processors introduced.
If this were true why would they want isolated grounds on computer circuits? Not to argue the software problem you are correct there.
I personally do not like isolated grounds because all equipment has a grounding wire attached to the case and all interfaces have ground wires in them that are attached to the case. Never had a problem with usb cables but with printer cables and monitor cables I have.
The computer is plugged into a isolated ground system and the monitor and printer are not. But as soon as you attach the cables they are all on the same ground. Problems come when there is a fault. The multiple grounds now become a current divider and split the fault current to different grounds. Sometimes the end result is a melted printer or monitor cable. Once it resulted in a fire. Now you can get isolators to separate the grounds.
Kind of like what neutral isolators try to do in the previous drawing.

The farm I spoke about had a feeder that left the substation and ran 3 miles to the east, then turned north for 6 miles and then back to the west 2 miles to the farm. The creek went from the farm to the substation.

Trouble call I will check the site tomorrow.
Thanks for the discussion

 

[Smart $]

Wow you got your own darn dedicated transformer!

Actually, there are [at least] three residential services (visible) run off that pot... but none of them are for my house

 

[RHJohnson]

Transformer Size

Transformer Size

Well - nobody answered this question yet.... A couple have been close, or made an accurate guess. If you look up at the can you will see large numbers, "usually yellow where I am now" , Something like "15" or maybe "30"
or even "37.5" - or other size indication. That is the KVA.....

In every life a little rain will fall, will this monsoon never end!

 

[72.5kv]

Well - nobody answered this question yet.... A couple have been close, or made an accurate guess. If you look up at the can you will see large numbers, "usually yellow where I am now" , Something like "15" or maybe "30"
or even "37.5" - or other size indication. That is the KVA.....

those number are the KVA rating of the unit. The loads power factor is not known so they are rated in KVA

 

[quogueelectric]

If you use a laptop

If you use a laptop

Something to ponder; If your pentium 4 processer runs on 1.8 volts and the neutral to ground voltage at the outlet is above that, is it any wonder why people see the blue screen of death on there computers more and more. How can the processor pass the interference off to ground?
Food for thought

you can pretty much plug doggie dodo into it and it will work. Look at the box in line with your power cord and you will see why.

 

[don_resqcapt19]

Loren,

I am not a IEEE member but there standard for computer feeders is 2.4 volts neutral to ground. Strangely enough it was passed in Las Vegas the same week the Pentium 4 processors introduced.

As far as I know that does not have any effect on the operation of the computer. In this application the voltage to ground is really a measurement of the voltage drop on the grounded conductor.

If this were true why would they want isolated grounds on computer circuits?

The use of an isolated ground will not change this number.

But as soon as you attach the cables they are all on the same ground.

Only if the cables between the different parts of the sytem include a ground reference. This is no longer common.
Don

 

[quogueelectric]

Is this number 2.4????

Is this number 2.4????

A tolerance for voltage drop on a neutral or is it the threshhold voltage at which a pulse is considered a 1 or a 0

 

[Pierre C Belarge]

quoqueelecgtric,
There is a "return" conductor on almost all primary distribution in the US. Single Wire Earth Return (SWER) is very rare here. In our distribution the primary and secondary grounded conductor is often the same conductor. That being said, the multigrounded neutral system does place the earth in parallel with the utility grounded conductor and there will be some grounded conductor current flowing in the earth. This current is often the source of "stray voltage" at dairy farms and pools.

As far as current flowing to ground, that does not happen .... current only flow back to its source...the ground or earth may be a conductor for some of that current.
Don

this is also true for highly congested urban areas. I have been told by linemen that the overhead has not been increased in a very long time, and the neutral current loads have...hence the earth is carrying more utility current than ever before. Don does a nice job in his post of explaining this.

I read in one post that the Utility installs a ground at every pole. Con Edison (NYC and a few locals outside of the city) grounds at poles with equipment or surge equipment only, or as Don has mentioned, 4 times per mile. Half of the grounds have been compromised along the way. I wonder how many are really effective???

 

[quogueelectric]

A true earth ground may

A true earth ground may

Verry well be a better conductor than 20 miles of spliced clamped and weather deteriorated counterpoise wire. when you figure for ohms in a parallell path what do you get when you insert infinity as number of conductors??where will the majority of primary current go even with a neutral??

 

[wirenut1980]

this is also true for highly congested urban areas. I have been told by linemen that the overhead has not been increased in a very long time, and the neutral current loads have...hence the earth is carrying more utility current than ever before. Don does a nice job in his post of explaining this.

I read in one post that the Utility installs a ground at every pole. Con Edison (NYC and a few locals outside of the city) grounds at poles with equipment or surge equipment only, or as Don has mentioned, 4 times per mile. Half of the grounds have been compromised along the way. I wonder how many are really effective???

I am a distribution engineer for a utility company. The NESC requires 4 "grounds" per mile. I have been taught that the word, "grounds" means a ground rod, with a #6 or #4 Cu wire run up to the medium voltage neutral (I use #4 Cu). I have been taught that a butt wrap ground is good for about 1/8th of a ground rod. I install ground rods at all poles with transformers and/or arrestors. On all other poles I install a butt wrap #4 Cu ground wire only.

One problem that many utilities are experiencing is copper theft at distribution poles and at substations. Having a bunch of pole ground wires cut off the poles can be hazardous for equipment and cause many stray voltage problems.

The amount of homes fed by a single phase transformer will depend on size of homes, size of air conditioners (for secondary voltage flicker), secondary wire sizes.


Dave

 

[quogueelectric]

Dave in your opinion

Dave in your opinion

I am a distribution engineer for a utility company. The NESC requires 4 "grounds" per mile. I have been taught that the word, "grounds" means a ground rod, with a #6 or #4 Cu wire run up to the medium voltage neutral (I use #4 Cu). I have been taught that a butt wrap ground is good for about 1/8th of a ground rod. I install ground rods at all poles with transformers and/or arrestors. On all other poles I install a butt wrap #4 Cu ground wire only.

One problem that many utilities are experiencing is copper theft at distribution poles and at substations. Having a bunch of pole ground wires cut off the poles can be hazardous for equipment and cause many stray voltage problems.

The amount of homes fed by a single phase transformer will depend on size of homes, size of air conditioners (for secondary voltage flicker), secondary wire sizes.


Dave

Dave in your opinion.. Does current flow to ground??

 

[mdshunk]

Dave in your opinion.. Does current flow to ground??

Of course it does. Kirchoff's law. Can't say that enough. Snap an amp clamp around a down ground, and you can measure it.

 

[iwire]

Of course it does. Kirchoff's law. Can't say that enough. Snap an amp clamp around a down ground, and you can measure it.

Now hold on a minute lets be clear.

Current does not flow 'to' ground any more than current will flow 'to' any conductor.

Current flows back to the source, it may use the earth as a conductor to get there.

Marc, I know you know that, but I have an idea what quogueelectric was after.

 

[mdshunk]

Marc, I know you know that, but I have an idea what quogueelectric was after.

Yeah, substitute "through ground" where he wrote "to ground".

 

[wirenut1980]

Dave in your opinion.. Does current flow to ground??

Yes, I agree with Marc. For your return current on a multi-grounded wye system, you have 2 paths:

1) along the primary neutral on the poles back to the substation transformer neutral bushing

2) from the primary neutral to the pole grounding conductor, to the electrode, to the earth, to the ground ring at the substation, up the ground wire at the substation transformer, and finally to the transformer neutral bushing.

The impedance of path 1 <<<2 normally, anyways, even when the distance is miles in length.

 

[quogueelectric]

as a ratio is it monitered in the substation

as a ratio is it monitered in the substation

Yes, I agree with Marc. For your return current on a multi-grounded wye system, you have 2 paths:

1) along the primary neutral on the poles back to the substation transformer neutral bushing

2) from the primary neutral to the pole grounding conductor, to the electrode, to the earth, to the ground ring at the substation, up the ground wire at the substation transformer, and finally to the transformer neutral bushing.

The impedance of path 1 <<<2 normally, anyways, even when the distance is miles in length.

As to what % comes back as stray

 

[wirenut1980]

As to what % comes back as stray

No it is not monitored. I'm not sure how one could do that cost effectively (to where data gathered could be meaningful, i.e. identify where the stray voltage is coming from). We take a more reactive approach, and respond to customer complaints. We also try as much as possible to keep an eye on our overhead and make sure the neutral and pole grounds are not compromised.