Importance of Voltages

Why those particular voltages??

I honestly don't know... Obviously the last two refer to single phase voltage and three phase.

Also the higher voltages are to allow more efficient power distribution, i.e. having lower I^2 x R losses, but suffering from other losses, corona discharge, insulation costs etc...

I think the way the National grid was designed in the UK was for the highest voltage to be for the longest / most power routes, and lower voltages for shorter routes requiring less expensive insulation and higher safety concerns?

I will be interested in anyone else's ideas...

John.

Because without voltage, current does not flow. And if current doesn't flow, work is not performed. If work is not performed, pay is not received. If pay is not received, spouse is not happy and refuses to allow you to have sex with them.

So the bottom line is, voltages are for sex.

There's always someone who can reduce the problem to one of sex isn't there?

Sex is the answer to everything, life, the universe.... and now the voltage supply system....

John.

"Sex is the answer to everything, life, the universe.... and now the voltage supply system...."

Sorry I have to disagree, I thought everybody knew that the answer to life the universe and everything was

FORTY_TWO!

There was an earlier thread on various voltage and frequency standards around the world, (Voltages Generated from Power Plants) which you can search to and read. There is a also a discussion on voltages coming in "multiples of eleven" which you can search to, and find.

thanks sir,but even i that thread i didnot find the appopriate answer there thats y i posted the thread once again so that new members may answer it

Exactly the topic had long before been discussed

I guess these are just standard, and all are the multyple of 110,

To the best of my knowladge last one should be 220 V, and there is one more standard of 110 V.

Why 60 Hertz or 50 CPS? Human senses begin to detect cycles at 50Hz and below. Headaches kick in at 50 cps for some. Seeing darkness between the light is distracting. DC is not economically transmitted long distances so the utilities selected the ac voltage most dangerous to interruption of heartbeats - 110 VAC at 50-60 Hz. At the time, most perceived a higher voltage or higher frequency would be more hazardous. Recent evidence verifies voltages higher than 110VAC are actually less likely to result in instant death. At 240VAC, for example, The heart clamps rather than fillibrates, protects itself, and allows rescue time. Utilities had no method nor could anyone suspect or anticipate said results at the time.

Once 110VAC became the standard and demand for more power was necessary to power electric cooking ranges and clothes dryers - well, with one neutral between two 110VAC out of phase, one had a natural 220VAC that was considered safe as 110VAC. Not true but the decision was not reversable.

Once the 110VAC, 220 VAC out of phase with a neutral became standard the desire was to transmitt more power further distances. Higher voltages were required with each voltage a multiple around a neutral. The demand for higher power transmission continues to increase with the latest idea being the hope to utilize super conductors for electrical transmission over long distances. Once perfected, central generators are perceived to be more economical than to haul coal over long distances to local power plants.

Please don't wake the sleeping giants, but, pizzzzt, Local point of use power generation is now more economical than grid transmission. Kenya, California, North Eureka and North Carolina know nothing cost less than local point-of-use solar, wind, hydro, local annual renewable corn ethanol, soy bean methanol, whole kernel shelled Tennessee cornstove corn heat. True there are some technological "tricks of the trade" that must be utilized in conjunction for economy. For example, a corn stove using 100 watts electrical is a no brainer for solar or wind generation of home and small business heat.

Congratulations!

You managed to get just about everything wrong.

Wouldst thou care to elaborate!

Please back up your claims regarding ventricular fibrillation in relation to 110VAC/240VAC (preferably with some links to verifiable website(s)) as this is news to me and my industry. Also, headaches at 50Hz? Were you talking about fluorscent light flicker due to supply line frequency, as this also occurs at 60Hz? Seeing darkness between the light is distracting? this is not how light flicker works!

Your comments regarding local point-of-use power as opposed to grid power are (like your previous posts) still misleading to say the least (and with regard to solar, completely and utterly wrong).

I myself am able to detect frequencies up to around 16000Hz.

it's all about SQR 3 ! SQR(3) is the factor in a three phase system between star and delta. (voltage between two phases is 1.73 (SQR 3) times higher than voltage between phase and neutral.)

the 110 actually is 127.

multiplied by SQR 3 : 220

multiplied by SQR 3 : 380

multiplied by SQR 3 : 660

In agreement with Manufacturers of electric devices, electricity producers are raising the tension little by little. If the voltage raises with 10%, this means that the same cables can transport 10% more energy. In most places the "good old" 220V is somewhere between 230 and 240 now... In a few years, the standard (in Europe) is gonna be 240.

"In agreement with Manufacturers of electric devices, electricity producers are raising the tension little by little. If the voltage raises with 10%, this means that the same cables can transport 10% more energy."

Line losses are calculated using the following formula

P = I² x R

Where R is the resistance in the line and I is the current

Now by increasing the voltage by 10% we reduce the current by 10% therefore

P = 90%² = 81%

So we reduce the line losses to 81% of what they would have been.

Thus a 10% increase in the voltage on a transmission line will reduce the loss due to resistance by 19% not 10% and this is precisely why they try and have as high a voltage as is practical on high tension transmission lines.

thanks for your mathematical addition, masu ...

Some of the responses are partly correct but the fundamental reason is rotating machinery, transformation ratios and the way the industry developed. There are several handbooks that review that history and a particularly good one is "Turning Points in American Electrical History", edited by James E. Brittain, published by IEEE Press. That's American history but it applies as well to International development. It's worth reading.

Earlier, someone suggested that AC is better than DC for transmission of power over long distances. Wrong! DC is far more efficient for transmission of power over long distances from generation to load centers. In North America, the reason so many long AC transmission lines exist was the difficulty of conversion from DC to AC at the time the lines were built. That is no longer the case.

Early differences in philosophy between Thomas Edison and George Westinghouse are interesting. Edison was convinced that DC was safer (and his first commercial installations were DC) while Westinghouse believed in AC. They battled it out for several years and Westinghouse eventually won.

EE Handbooks also include some of that history, along with discussions on standard generation, transmission and distribution voltages and how they were developed.

I agree with Bluestone......it has to do with rotating machinery. If you look at turbine or diesel gen' sets, hydro-electric generators, wind generators, fossil fuel generating stations, etc., there is a predetermined ratio of windings that equate to the output voltage of the device. Many years ago, some very brilliant minds came together, perhaps maybe over a beer or two, and established a certain set of standard transmission voltages that would work with the entire US grid, regardless of the motive energy used. Now, did someone just simply suggest "13.8 kv is great", I dunno. I may have to read the book that Bluestone suggests.

As for the DC transmissions over long distances, yes it is much more efficient over the "long haul". California Edison is actually utilizing a DC transmission line from a substation here in So Cal to another substation in Canada. Next time I talk with my buddy that works for Edison, I will get some "fun facts" about the DC line and post them here.

I agree Bluestone, dc is far more efficient than ac...

The UK - France power link under the channel is dc high voltage, purely because the capacitance of the 200 mile cable makes it extremely lossy for ac transmission as well as the fact that there is no requirement to match frequencies or phase etc...

It also makes for an interesting switching problem, imagine a very high voltage cable carrying many amperes at many 100's of kilovolts with a cable capacitance of over 100's microFarads, just imagine switching that lot off and on!!

Its not just the capacitance but the inductance as well, as it acts like a transmission line, apparently the switch gear is very impressive!

John.

The problem with using DC instead of AC is that any gain in the transmission side is lost due to the inefficiencies of altering the voltage. For example if a generator was working at 1,200 volts you need to step this up for transmission and then at the other end drop it back to a useable voltage. I can't be sure but I would expect that doing this with DC would counter any gains over doing the same with AC.

I do not know how voltage conversion is achieved with the link between England and France but it would bee interesting to now how they do it and what sort of losses occur. I think the main problem was that the undersea cables have unique problems that above ground cables don't.

Comparatively the distances that power is transmitted over in the USA and Australia is much greater than one would see in Europe and definitely further than it is across the English Channel.

Masu, I seem to remember that in Russia they have several extremely long transmission lines and they found that using dc at 2 million volts was far more efficient...

There wasn't too much information in the article about it as it was in the cold war days, but there definitely was a valid argument for using dc...

The England - France link was operating in the early 70's so I'm guessing they probably used gensets to change from dc to ac, sort of dc motor drives ac generator?

John.

The higher the voltage the greater the amount of power that can be transmitted over a longer distance utilizing a smaller conductor resulting in less voltage drop.

Where my Staples "That was easy button!"

Yes, but the original question was

"Why voltages are generated,transmitted ,distributed of only particularly 440kv,132kv,33kv,11kv,6.6kv,440v,230v....?"

i.e.- why these specific voltages and not, say, 90V or 3145V AC?

How about 380V, 550V, 110V, 115V, 120V, 220V, 240V, 277V, 4800V - Seems as if (to me) the question can't be answered as the values you give are not the only voltages used!

Jmart23

The question is still valid because although the voltage standards (detailing the base phase voltage and the increasing voltage increments right up to EHT voltage) vary to some extent, there are only a few main voltage standards that everyone works to (about 3 or 4 main ones and 2 or 3 minor ones for everyone in the world). Standardisation is still standardisation, even when there are a few different standards.

In this Modern World every one needed high power with good stamina.

In electricity also we need high power, Because day by day our usage in Electrical or electronics iteams are very high.

Now a days Power trans mission is High Voltage AC and Distribution is Low voltage (220/110 V).

But we take the stamina or stability of a power system means high voltage always make system stable, today we are now living in a world of UHVAC and UHVDC systems (UHV = Ultra high Voltage). Now a days we can able to increase the Voltage upto what we need also we can change HVDC to HVAC or Vise versa.

But in olden days generation is restricted upto 11KV AC only (because of insulation problem) ther is no HVDC, so they used 3 phase power transformers to transfer the power (to make system as economical and stability).

As per mathamatical calculation, Number of turns ration we fixed in the transformer give that much output voltage.

Formula: N1/N2 = V1/V2 = I2/I1

No one think to fix 2.5 truns or 3.8 turns etc 9because it may leads to confusion), thats why we get 22KV, 33KV etc., in multiple of 11KV.

Today the trend is entirely changed, we have automatic on-linecontroller to correct our voltage even in grid level.

But in order to make as a standart still in Distribution transformer we are using 11kv/230V or 110V. but in all other places (even in generation and in grid level) it will vary not in multiple of 11 now.

Thank you.

K.P.Mahalingam,

Electrical and electronics engineer,

INDIA

Some how the standard make all easier, isn't it? for transmit those voltage actually is come from transformer, as such, the standard transformer are apply rather than customize transformer make it expensive. For different area have a different voltage distribute, some area have a long travel distance from main station, so from power formula, large V will produce the small I, as such, it will reduce the area of conductor as such, transmitter line need not to having the big and huge conductor, all this is Cos actually.