Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: Why Is AC-Current More Efficient Over Long Distances ?  (Read 14011 times)

Magluvin

  • Hero Member
  • *****
  • Posts: 5884
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #15 on: January 16, 2017, 06:50:17 AM »
AC isn't more efficient to transfer than DC.  DC is.

AC suffers inductive and capacitive losses as well as skin-effect and proximity-effect.
AC is easier to transform up and down, though, but that has nothing to do with distance.

Skin effect is more at high freq, not at 60 or 50hz, I believe.

Havnt tried it yet but say if we have to run an extension cord 100ft from a 120v AC outlet to run a 300w halogen work light.  If we replaced the extension cord with 2 separate wires that were say 3ft apart for the 100ft, would there be any change in power at the light in these 2 situations?  Lets exclude the 3rd ground wire for this idea.

I am thinking that when the 2 wires are close together, even twisted pair as in the extension cord, would transfer the power to the light better than the separated ones, and the mutual induction of each wire to the other compliment current flow, where the separated wires would have to deal with their own self induction possibly reducing the output to the light in comparison.

Mags

tagor

  • Hero Member
  • *****
  • Posts: 1333
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #16 on: January 16, 2017, 08:06:42 AM »

https://en.wikipedia.org/wiki/HVDC_Cross-Channel

Quote
2000 MW system (1986)Because the first installation did not meet increasing requirements, it was replaced in 1975–1986 by a new HVDC system with a maximum transmission rating of 2,000 MW between France and Great Britain, for which two new converter stations were built in Sellindge (UK) and in Bonningues-lès-Calais (Les Mandarins station), near Calais, (France). Unlike most HVDC schemes, where the two converter stations are built by the same manufacturer, the two converter stations of the 2,000 MW scheme were built by different manufacturers (although both have subsequently become part of the same parent company, Alstom). The Sellindge converter station was built by GEC[3] and the Les Mandarins converter station was built by CGE Alsthom.
This HVDC-link is 73 kilometres (45 mi) long in route, with 70 kilometres (43 mi) between the two ends. The undersea section consists of eight 46 kilometres (29 mi) long 270 kV submarine cables, laid between Folkestone (UK) and Sangatte (France), arranged as two fully independent 1,000 MW Bipoles, each operated at a DC voltage of ±270 kV. Cables are laid in pairs in four trenches so that the magnetic fields generated by the two conductors are largely cancelled. The landside parts of the link consist of 8 cables with lengths of 18.5 kilometres (11.5 mi) in England, and 6.35 kilometres (3.95 mi) in France.[4]
In common with the 1961 scheme, there is no provision to permit neutral current to flow through the sea. Although each station includes an earth electrode, this is used only to provide a neutral reference, and only one of the two electrodes is connected at a given time so that there can be no current flow between them.
The system was built with solid-state semiconductor thyristor valves from the outset. Initially these were air-cooled and used analogue control systems but in 2011 and 2012 respectively, the thyristor valves of Bipole 1 and Bipole 2 were replaced by more modern water-cooled thyristor valves and digital control systems supplied by Alstom.[5]
This system remains the world's largest-capacity submarine cable HVDC system.[citation needed]
In November 2016 during Storm Angus a ship dragging an anchor cut four of the eight cable components, reducing capacity by 50%.[6] It is expected that repairs will be completed by February 2017

Doug1

  • Hero Member
  • *****
  • Posts: 763
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #17 on: January 16, 2017, 01:59:53 PM »
Skin effect is more at high freq, not at 60 or 50hz, I believe.

Havnt tried it yet but say if we have to run an extension cord 100ft from a 120v AC outlet to run a 300w halogen work light.  If we replaced the extension cord with 2 separate wires that were say 3ft apart for the 100ft, would there be any change in power at the light in these 2 situations?  Lets exclude the 3rd ground wire for this idea.

I am thinking that when the 2 wires are close together, even twisted pair as in the extension cord, would transfer the power to the light better than the separated ones, and the mutual induction of each wire to the other compliment current flow, where the separated wires would have to deal with their own self induction possibly reducing the output to the light in comparison.

Mags

 Look up ,up at the transmission lines. See any twisted pairs? See any twisted pairs going from HV high towers to the substations? You have to also realize there will be some greater measure of magnetic interference with other conductors in a non cancelled condition which might not be too healthy.

mscoffman

  • Hero Member
  • *****
  • Posts: 1377
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #18 on: January 16, 2017, 02:30:20 PM »

These above items reminds me of when they first started putting Celluar Phone antennas on active high voltage AC power distribution towers at least around here.
That has to be as tricky as heck because the dimensional control of the cell radio feed has to do duplexing (transmitting and receiving nearby frequencies at the same time)
means they have to run signals through copper pipe like conductors. If lightning triggered power discharges into the RF radio equipment I doubt it would last very
long. Also even the small continuous static discharges have got to be radio noisy. I have to salute the designers who first thought they could do this and the technicians
that work on this type of equipment.


Jeg

  • Hero Member
  • *****
  • Posts: 1532
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #19 on: January 16, 2017, 03:05:08 PM »
Also Leedskalnin has said something related to this.

"You have been wondering why alternating currents can run so far away from their generators. One reason is between every time the currents start and stop there is no pressure in the wire so the magnets from the air run in the wire and when the run starts there already are magnets in the wire which do not have to come from the generator, so the power line itself is a small generator which assists the big generator to furnish the magnets for the currents to run with. I have a generator that generates currents on a small scale from the air without using any magnets around it."

wattsup

  • Hero Member
  • *****
  • Posts: 2606
    • Spin Conveyance Theory - For a New Perspective...
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #20 on: January 18, 2017, 03:05:05 PM »
@for the question - a different view

DC is like having two water hoses open at the same time. That's why most dc coils when they burn up do so near the center point.

AC is like one hose is a drain open to the atmosphere, and the other hose where during half a cycle it pumps and during the other half a cycle it is in suction and this creates a STATIONARY change via the inertial changes being seen by our slip rings like a one directional ratchet where one way or the other turns the socket in the same direction.

Both types never really pump but DC is dual push, ac is single push/pull where in both cases there is never any real FLOW of anything. There is only a conveyance. Like when you go to a huge stadium and see the human wave where people stand up then sit as the wave point passes them. The wave is conveyed but no one really moved out of their position.

There is no such thing as alternating current in the sense that we have been taught that the output is on the hot for half a cycle and on the neutral for the other half a cycle. Try and prove me wrong. hehehe

DC is more of an adversarial power source with both sides looking to take over the pulsed object where as AC is more of a one handed taunting of the coil. Tesla, if he took the AC further would have invented Dual AC but there was no need for that then and 180 degree offsets where not easy to make.

AC should be called Single Wire Seesaw Current. Or you can call it also Single wire Push/Pull. That's why AC can be conveyed for such long distances because the higher the applied voltage the deeper (or further) the conveyance can reach without too much loss. Voltage is distance. Amperage is the number of atoms involved in the distance conveyance. A concept thunder (or your spark gap) has learned long ago.

If in these simple DC to AC comparisons, some here can jump the fence from the Standard bullshit to the new side of the fence, you will start to see effects in a totally different and more direct and realistic manner. You will soon then realize that all this electron/field crap we have been fed was only an illusion reinforced by our normal desire to manifest notions in our minds in the most accepted form as being "SAFE to talk about".

Our present notions are only accepted because peoples jobs are at stake, and regardless if society is following a false or true concept, the toys still work. But in order to arrive at a next generation of toys, if the concept stays the same, there will be no next, there will only be a continuation of the same. The same road leading to the same losses while this other road will lead to OU, levitation as being an atomic inertial effect and NOT FIELD RELATED, new types of wire with more oriented atoms producing hyper super conductivity at ambient temperatures instead of requiring absolute freezing to produce what we call super conductivity today, is just a furt in the windstorm.

With the new notions, we will build transformers with 1" long secondaries directly going to load. With the new notions, EE math will be simplified to its extreme. Electrical potential will be seen as degrees of nucleic sway, materials will be chosen for their nucleic reactance, this will change how we see mass, our bodies, liquid, gas, plasma, will all be seen in a new light. Xrays will finally be seen as an inward effect and not this outward radiating ray that cuts through everything organic.

But you can only realize you need to look elsewhere when you arrive at the edge of the forest understand that your world is much greater then the barren outskirts of your domain. Only if you thirst for something that you know in fact has to exist in another manner then how you see it today. It requires a WILLINGNESS to push your mind out of the stranglehold of present concepts. There is no other way. A pill won't do it, watching TV won't do it, going to work won't do it, even praying 10 hours a day won't do it. Only your mental intention to push yourself beyond your present limits will even start to kindle the fire that can then grow inside you as a new method of normality. The toys will stay the same for a while, but then, they will morph into quasi living entities with reacting atoms at every nick and cranny of the object.

Happy New Years 2017 to all.

wattsup

citfta

  • Hero Member
  • *****
  • Posts: 1050
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #21 on: January 20, 2017, 02:58:14 AM »
Skin effect is more at high freq, not at 60 or 50hz, I believe.

Havnt tried it yet but say if we have to run an extension cord 100ft from a 120v AC outlet to run a 300w halogen work light.  If we replaced the extension cord with 2 separate wires that were say 3ft apart for the 100ft, would there be any change in power at the light in these 2 situations?  Lets exclude the 3rd ground wire for this idea.

I am thinking that when the 2 wires are close together, even twisted pair as in the extension cord, would transfer the power to the light better than the separated ones, and the mutual induction of each wire to the other compliment current flow, where the separated wires would have to deal with their own self induction possibly reducing the output to the light in comparison.

Mags


Hi Mags,

You are correct that running single wires that are separated would not transfer the power as well as a regular extension cord where the wires are next to each other.  But the reason you are correct is not only what you surmised.  The wires running next to each other also cancel the inducing ability of each other.  I once saw a machine designed by an engineer that was not familiar with this function.  He ran the three different phases of power in three separate conduits.  When the machine was first turned on it started making a very loud humming sound and the conduits started smoking.  Each phase being in it's own conduit allowed those wires to induce tremendous eddy currents in the conduits.  We had to completely rewire the machine before it worked properly.  In your extension cord example the returning current is cancelling the outgoing currents magnetic field and therefore there is not a strong enough field to induce eddy currents in any nearby metal objects or in any metal conduit if conduit is being used.

Carroll

AlienGrey

  • Hero Member
  • *****
  • Posts: 3713
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #22 on: January 22, 2017, 11:17:21 AM »
Because it is an action of the active motion of the sine wave it's dynamic it needs some where to go or disparate, it's realy obvious with the way it's generated. Eric Dollard is your man he explains it in one of his videos. If i shoved you in a tube and kept shoving things in behind you you would have to move along or out the other side or bang you explode into fragments AC energy is the same.

Dave45

  • Guest
Re: Why Is AC-Current More Efficient Over Long Distances ?
« Reply #23 on: January 22, 2017, 03:35:30 PM »
I was playing with small ring magnets letting them spiral down a welding rod an notice they would want to change direction before they reached the bottom, it was like the field tightened up if it only spun in one direction, at least that was the thought that came to mind watching it.
Also if you try to push a wire through a.conduit it tightens up but if you push and pull it moves through the.conduit much easier.