Internation standard



In six-phase 'double-wye' the phase-to-neutral and phase-to-immediately-adjacent-phase voltages are equal. Ref IEEE Std C57.12.70 6.
s falke
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where
easier
each
Hepcats call this 6/12 stuff "high phase order" www.shawgrp.com/PTI/consulting/transmission/high_phase_order.cfm
s falke
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|
|> |> >Yes, 6 phase on the left, 12 phase on the right. I don't really know where |> >it is. Supposedly by having more phases like that, wire spacing is easier |> >to do. At a 30 degree phase angle, the potential between conductors is a |> >bit more than half the line to ground voltage. So if the voltage from each |> >line to ground is 69000, then from line to cloest line is just 35717. |> |> yeah, I noticed the insulators between the wires were smaller than those |> from them to the tower, and figured that being fairly close to being in |> phase the voltage between them would be lower, though I didn't work out |> the math. | | In six-phase 'double-wye' the phase-to-neutral and | phase-to-immediately-adjacent-phase voltages are equal. | Ref IEEE Std C57.12.70 ?6.
Does IEEE talk any about twelve-phase?
The six phase configuration, of course, is with each angle at 60 degrees which will do same voltage between each phase.
What I find interesting is that the cross section of that transmission line is a representation of the phase vector diagram. Imagine doubling the 12 phase system to 24 phases, nearly cutting the line to line voltage in half yet again. Then split it further to 48 phase, then 96, then 192, and so on. You'd be approaching a solid tubular conductor that way.
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On Fri, 23 Apr 2004 18:11:56 +0000 (UTC) Michael Moroney
| snipped-for-privacy@ipal.net writes: | |>Yes, 6 phase on the left, 12 phase on the right. I don't really know where |>it is. Supposedly by having more phases like that, wire spacing is easier |>to do. At a 30 degree phase angle, the potential between conductors is a |>bit more than half the line to ground voltage. So if the voltage from each |>line to ground is 69000, then from line to cloest line is just 35717. | | yeah, I noticed the insulators between the wires were smaller than those | from them to the tower, and figured that being fairly close to being in | phase the voltage between them would be lower, though I didn't work out | the math.
Hitting 35717.028224148 requires the math. But you can simply visualize the vector diagram right on that 12 phase attachment and see the reduction.
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On 24 Apr 2004 07:05:24 GMT snipped-for-privacy@ipal.net wrote: | On Fri, 23 Apr 2004 18:11:56 +0000 (UTC) Michael Moroney
| | snipped-for-privacy@ipal.net writes: | | | |>Yes, 6 phase on the left, 12 phase on the right. I don't really know where | |>it is. Supposedly by having more phases like that, wire spacing is easier | |>to do. At a 30 degree phase angle, the potential between conductors is a | |>bit more than half the line to ground voltage. So if the voltage from each | |>line to ground is 69000, then from line to cloest line is just 35717. | | | | yeah, I noticed the insulators between the wires were smaller than those | | from them to the tower, and figured that being fairly close to being in | | phase the voltage between them would be lower, though I didn't work out | | the math. | | Hitting 35717.028224148 requires the math. But you can simply visualize | the vector diagram right on that 12 phase attachment and see the reduction.
I ran the calculations on more phases, to extreme, based on 69000 volts:
phases voltage ------- ---------------- 6 69000.00000000 12 35717.02822415 24 18012.61452637 48 9025.63183376 96 4515.23342940 192 2257.91896446 384 1128.99726534 768 564.50335562 1536 282.25226818 3072 141.12620789 6144 70.56311317 12288 35.28155774 24576 17.64077901 49152 8.82038952 98304 4.41019476 196608 2.20509738 393216 1.10254869 786432 0.55127435 1572864 0.27563717 3145728 0.13781859 6291456 0.06890929
and based on 1000000 volts:
phases voltage ------- ---------------- 6 1000000.00000000 12 517638.09020504 24 261052.38444010 48 130806.25846029 96 65438.16564355 192 32723.46325297 384 16362.27920787 768 8181.20805247 1536 4090.61258233 3072 2045.30736068 6144 1022.65381403 12288 511.32692372 24576 255.66346395 49152 127.83173224 98304 63.91586615 196608 31.95793308 393216 15.97896654 786432 7.98948327 1572864 3.99474163 3145728 1.99737082 6291456 0.99868541
Now, who would like to construct a tube with 6291456 tiny parallel wires over a length of a transmission line, or the transformer array needed to convert the phases. :-)
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To get more power over an existing limited right-of-way, wouldn't it be more economical to just build higher towers with conventional 3-phase conductors at higher voltages? (With the understanding that there might be height restrictions near airports, etc.)
Asthetically, I think these HPO towers would "freak-out" owners with property adjacent to the right-of-way. To me, transmission towers and substations are usually a thing of beauty. I think these things are a bit on the ugly side, however.
Beachcomber
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| To get more power over an existing limited right-of-way, wouldn't it | be more economical to just build higher towers with conventional | 3-phase conductors at higher voltages? (With the understanding that | there might be height restrictions near airports, etc.) | | Asthetically, I think these HPO towers would "freak-out" owners with | property adjacent to the right-of-way. To me, transmission towers and | substations are usually a thing of beauty. I think these things are a | bit on the ugly side, however.
I rather like them, especially at 12 phases.
I'd be one of those who would "freak-out" if an adjacent transmission line were doubled in height and voltage. But doubling or quadrupling the number of wires in an HPO line at the same height would not. When I would have visitors over, I'd tell them made up stories about how the wires are used to entrap magnetic fields, or it's a design they got from space aliens, or such.
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snipped-for-privacy@ipal.net writes:

...
There's another use for such "multiphase" transmission lines. Right now long AC transmission lines are unstable due to phase shift, but the long wavelength at 60 Hz (5,000 km) means it takes a length of 1666.666 km to by one complete phase (A becomes B, B becomes C, C A), so there are problems if a substation is fed through routes of different lengths. But with 6291456 phases :-) the phases shift by 1 in about 112 cm, so two or more routes of different lengths can be matched to that distance precision.
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On Thu, 22 Apr 2004 19:57:59 +0000 (UTC) Michael Moroney
| snipped-for-privacy@ipal.net writes: | |>I'd rather adopt the 155 Hz 1680X/1188 volt two phase system they use on the |>Klingon home world :-) It's well optimized for painsticks. | | Is that something you made up or is it from some Star Trek "technology" | book/web site? How about the "1680X/1188" terminology? (makes perfect | sense, why didn't I think of that to describe a two phase system?) | 4 wire or 5? :-)
I made it up :-)
It could be done with 3 wires corner grounded, or just not grounded, too. Or 4 or 5. The X would suggest 4 or 5.
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The investments in these continental-wide power grids are enormous and won't be changing their standards anytime soon. Unlike the standards developed for TV systems (NTSC, PAL, SECAM), there is little to no technical or economic advantage (such as global HDTV) in switching over to a worldwide standard for power distribution.
In the US, as AC power developed from about the 1890's onward, there were all sorts of oddball frequencies in use, some as high as 133 Hz. As the larger grids were formed, the default frequency of standardization became 60 Hz and the oddball equipment was scrapped.
The dominant electrical industrialists in Europe were the Germans and the Berlin electrical system became the European showcase and model for modern power transmission. The frequency selected was 50 Hz.
To the best of my knowledge, there was no worldwide conference on selecting a global electrical standard as there had been for setting the world's time zones (The French insisted that the prime meridian 0 degrees longitude must run through Paris, but the British held out for Greenwich, and won!) . Perhaps, at the time, the big industrial concerns like Siemens were interested in protecting their markets, but I think the choice was made without even imagining a global market for electrical products. In Europe, even though the voltage and frequency were standardized throughout the continent, every single country had their own unique plug and socket arrangement that persists to this day.
I still have trouble understanding why Japan is at 100 volts and half the country is at 50 Hz, the other half at 60 Hz. Does anyone know the particulars?
Beachcomber

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| To the best of my knowledge, there was no worldwide conference on | selecting a global electrical standard as there had been for setting | the world's time zones (The French insisted that the prime meridian 0 | degrees longitude must run through Paris, but the British held out for | Greenwich, and won!) . Perhaps, at the time, the big industrial | concerns like Siemens were interested in protecting their markets, but | I think the choice was made without even imagining a global market for | electrical products. In Europe, even though the voltage and | frequency were standardized throughout the continent, every single | country had their own unique plug and socket arrangement that persists | to this day.
And what was the frequency dependency of the primary consumer electrical product of the day? None. It was the light bulb. Industry had some concern since much of their usage was motors. But motor systems could be engineered around it easily enough.
| I still have trouble understanding why Japan is at 100 volts and half | the country is at 50 Hz, the other half at 60 Hz. Does anyone know | the particulars?
I'm not sure about the 100 volts, but the frequency difference could have been just from two major hold outs. At the time they didn't need to form a shared grid, so the remaining issue would be dependency on stuff that used the power. And it's not the critical.
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Actually, the primary consumer electrical product of the early years of the electrical age was the iron (see "The Electric City" by Harold L. Platt -1991), but you are correct in that it did not have a preferred frequency.
At one time, there were many satisfactory power distribution systems at 25 Hz. This was thought to be the ideal frequency for consumer and small industrial motors, transformers, etc. The New York Transit Authority used 25 Hz into the 1990's for distribution and rectification to DC to power the trains.
http://www.nycsubway.org/tech/power/rotary.html
It turns out that incandescent light bulbs do have a frequency dependency... The lower frequencies caused excessive flicker in the lower wattage lamps. Hence, 25 Hz was deemed unacceptable for residential consumer use and the higher 60 Hz value was picked for North America.
Beachcomber
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standard?
Question #1: Why? Why not change the rest of the world to 117 V AC, 60 Hz? I don't reside in the US, so I'm not biased toward their choice of voltage and frequency, but their choice was as good as any other - there were some pros to using 60 Hz (lower iron weight) and cons to using 110 V (more copper).
Question #2: Why stop at the electrical grid? Is the phone system the same all over the world? Start with the physical interface: in the US/Canada it is RJ-11 (6-pin modular), while in Europe there are/were at least 11 different types of plugs! Take another crack at the phone system: ringing tones - try to dial the UK or Australia and you get a different cadence.
Question #3: Back to the electrical grid - are all the electrical plugs around the world, with the exception of the US/Canada, the same? Hardly. To take it to the extreme: in the Philippines and some parts of Japan, they use the US style (NEMA 5-15, rated 110 V, 15A) to feed 220 V circuits!
Question #4: Another example - driving on the right side of the road vs. the left side of the road - which is better?
Question #5: TV broadcast standards - PAL, SECAM, NTSC - which is better?
You see, we can go forever with example of REGIONAL settings, and never come to a conclusion which is better or worst. The only forces to settles these things are the market when a new technology emerges (what the consumers wish and want, and the VHS vs. Beta is a fantastic example) or some kind of voluntary standardization (like what the IEC or ITU are striving to achieve). After that will come the question of the economic impact. With regards to the 110/60 vs. 220/50, chances are exactly ZERO that any economic block will change either way.
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