Transmission Lines above 1000 kV

Only if you're not a terrorist.

Can anyone give me information about any operational transmission lines with voltage level above 1000 kV. I have gone through some of the literatures where they talk about 1000 kV lines but currently operational at 500 kV in Russia & Japan, and some test lines in USA. But I was wandering if any commercial lines are still operational with such high voltage.

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735 and 765 KV lines have been operational since the '60's in Candad and the US 1200KV research lines exist but none operational that I know of as, either 765KV has proven adequate or DC links (say at +/-400KV) are often more feasible.

In the UK we don't have anything higher than 400kV; we also use 132kV and 275kV. Of course, our transmission distances are fairly short so I doubt that we'll se anything higher in future.

Russia have testing 1500 kV DC. Russia use 1150 kV AC.

Itaipu in Paraguay is linked to Brazil with a +500 kV / -500 kV DC link

A 18 kV to 525 kV transformer for 825 MVA and other photos here

Thats true that in russia there are test lines for 1500 kV and some operational lines for 1150 kV. But somewhere I read that the 1150 kV operational lines in russia are now being operated at 500 kV (since last 5-10 years). Initially these lines were operated at full system voltage but now they are reduced. does any one know the reason???

Also I have read of a similar test line in Japan which was initially operated at 1100 kV but afterwards was operated at 500 kV

Moreover there are several test lines in the USA, UK, Italy etc.

harsh

On 6 May 2007 02:59:37 -0700 contrex wrote: | On 6 May, 01:59, Ken wrote: |> On 4 May 2007 07:44:51 -0700, harsh wrote: |>

|> > Can anyone give me information about any operational transmission |> > lines with voltage level above 1000 kV. I have gone through some of |> > the literatures where they talk about 1000 kV lines but currently |> > operational at 500 kV in Russia & Japan, and some test lines in USA. |> > But I was wandering if any commercial lines are still operational |> > with such high voltage. |>

|> Russia have testing 1500 kV DC. |> Russia use 1150 kV AC. |>

|>

| | Itaipu in Paraguay is linked to Brazil with a +500 kV / -500 kV DC | link | | A 18 kV to 525 kV transformer for 825 MVA and other photos here | | Is that 525kV L-G or L-L?

It's a single-phase transformer.

| On 6 May, 13:44, snipped-for-privacy@ipal.net wrote: | |> Is that 525kV L-G or L-L? | | It's a single-phase transformer.

So. Unless the entire transmission line is single phase, that would have to be wired together with other transformers to make a three phase system. Most likely it would be Y (and hence L-G), but it could be D (and so L-L). If the former, then the L-L (delta) voltage would be 909kV.

OK I see what you mean. The transmission line is a DC bipole.

In the classic HVDC system as developed by ASEA in the 1950s, at the AC end a set of transformers, often three physically separate single- phase transformers, isolate the station from the AC supply, to provide a local earth, and to ensure the correct eventual DC voltage. The output of these transformers is then connected to a bridge rectifier formed by a number of valves. The basic configuration uses six valves, connecting each of the three phases to each of the DC rails. However, with a phase change only every sixty degrees, considerable harmonics remain on the DC rails.

An enhancement of this configuration uses 12 valves (often known as a twelve-pulse system). The AC is split into two separate three phase supplies before transformation. One of the sets of supplies is then configured to have a star (wye) secondary, the other a delta secondary, establishing a thirty degree phase difference between each of the sets of three phases. With twelve valves connecting each of the two sets of three phases to the two DC rails, there is a phase change every 30 degrees, and harmonics are considerably reduced.

On 7 May 2007 02:29:51 -0700 contrex wrote: | On 7 May, 02:45, snipped-for-privacy@ipal.net wrote: |> On 6 May 2007 14:59:12 -0700 contrex wrote: |>

|> | On 6 May, 13:44, snipped-for-privacy@ipal.net wrote: |> | |> |> Is that 525kV L-G or L-L? |> | |> | It's a single-phase transformer. |>

|> So. Unless the entire transmission line is single phase, that would have |> to be wired together with other transformers to make a three phase system. |> Most likely it would be Y (and hence L-G), but it could be D (and so L-L). |> If the former, then the L-L (delta) voltage would be 909kV. | | OK I see what you mean. The transmission line is a DC bipole.

Ah. Somewhere I missed that this was DC. My bad.

I'd like to know what is the highest voltage AC transmission in operation (not just a research project).

As far as I know, 765KV and this has been in operation since the '60's

The 268 mile long Ekibastuz - Kokshetau HVAC powerline in Kazakhstan which runs at 1150 kV entered service in 1988. It now forms part of the 1150 KiloVolt ultra high voltage long distance overhead electric power transportation line Itatsk - Barnaul - Ekibastuz - Kokchetav - Kustanay - Chelyabinsk which links Asia with Europe. Stretching for over 5000 kms it links Siberia through Kazakhstan with Ural.

There are 1150 KV links planned in China and there will be an International Symposium on International Standards for Ultra High Voltage in Beijing 18-21 July 2007

I am just curious.... What kind of techniques are used to minimize corona at those voltage levels? Is it four (or more) conductors (with spacers? That would seem to be a lot of cable for one of those 5000 km (3000 mile) runs in the old Soviet Union. Also, those transformers must have some big-a bushings on them...

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Yes, bundled conductors would be used -4 or more likely 6-8 per phase. Also this cost for a 5000km AC line would pale in comparison to the necessary reactive compensation to break the line up into about 7-10 or more sections, requiring reactive sources between sections (that is adequate generating capability at section junctions . AC transmission lines are typically well under 1/4 wavelength (wavelength at 60Hxz is 5000Km), such as the section you mention (430Km). Is this line, designed for 1100KV in service at that voltage? It appears that it may still be operated at 500KV which is below the 765KV in use for many years.

Yes, the bushings are large.

The following reference may be of interest

the 8 conductor bundles in the design.

I read that the Kazakhstan section was still run at 1150 although the Siberian sections of the Russian line have been run at 500 kv for some years