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#217620 - 09/18/16 09:25 AM 230 or 345 kV transmission lines?
Vlado Offline
Member

Registered: 02/28/11
Posts: 28
Loc: Croatia
Hi,
Please, take a look:
https://www.youtube.com/watch?v=NKnE61aaS9U
Are these 230 kV or 345 kV lines? Without much thinking, evaluating phase clearances and counting number of porcelain bells insulators in strings I would say it is 345 kV. However, there are two things that puzzle me. One power line has just one conductor per phase (no bundle), and 330 kV levels and above are bundle conductors on regular basis.However,I don't live in the states. Anybody from Pensylvannia?

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#217627 - 09/19/16 09:09 PM Re: 230 or 345 kV transmission lines? [Re: Vlado]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
Wild guess is 250kv.
BTW there are some good videos in the side bar next to that one. I watched for about an hour.
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Greg Fretwell

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#217628 - 09/20/16 06:09 AM Re: 230 or 345 kV transmission lines? [Re: gfretwell]
Vlado Offline
Member

Registered: 02/28/11
Posts: 28
Loc: Croatia
I think can't be 250 since that's not standardized in USA. Here you can see standardized EHV voltages in the states:


Hard to tell just by the insulators (changes form location to location). Difference between 230 and 345 isn't so big


Edited by Vlado (09/20/16 06:11 AM)

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#217633 - 09/20/16 10:18 AM Re: 230 or 345 kV transmission lines? [Re: Vlado]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
Dunno, that is just what the FPL guy told me about the line behind my house. Maybe they round it off or something.

This is supposed to be 250kv and two 48 kvs



Next time I see the guys working at the sub station I will ask again
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#217634 - 09/20/16 11:24 AM Re: 230 or 345 kV transmission lines? [Re: gfretwell]
Vlado Offline
Member

Registered: 02/28/11
Posts: 28
Loc: Croatia
Yes, probably he rounded it. For systems with nominal voltage 230 kV ac, maximum allowed continuous operating voltage is 245 kV. 250 is close to that

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#217635 - 09/20/16 12:32 PM Re: 230 or 345 kV transmission lines? [Re: Vlado]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6804
Loc: Brick, NJ USA
Recently had two (2) 500Kv circuits installed on monopole towers into our switchyard from a plant 2 towns northeast.

I thought about taking a pic this AM, but with the current high state of alert here, I don't need Homeland Security on my case.

The monopoles replaced old lattice towers.
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#217636 - 09/20/16 01:31 PM Re: 230 or 345 kV transmission lines? [Re: Vlado]
Vlado Offline
Member

Registered: 02/28/11
Posts: 28
Loc: Croatia
"Compactifaction" of power lines is a modern trend almost everywhere today. Note however that wooden poles in the yt video are very old fashioned style. Something like that you will not find in EU, especially not above 200 kV level!

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#217641 - 09/23/16 11:35 AM Re: 230 or 345 kV transmission lines? [Re: Vlado]
Vlado Offline
Member

Registered: 02/28/11
Posts: 28
Loc: Croatia
Ok, if this isn't some monkey business but proper engineering design, this has to be 230 kV. Althought I've never seen a 220 kV pylon with as many as 18 standard disc units in a suspension string in EU (I think 16 being the most), that number can vary on several things (altitude, predicted contamination/polution level etc). OTOH, I heard there are still operating 345 kV lines with single conductor per phase somewhere in the states. And these are rare. In such cases used ACSR conductors are massive (dia> 1.7"). More importantly, corona suppression rings are put on ends of insulators with no exception.

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#217643 - 09/24/16 09:33 AM Re: 230 or 345 kV transmission lines? [Re: Vlado]
Vlado Offline
Member

Registered: 02/28/11
Posts: 28
Loc: Croatia
345 kV with a single massive conductor per phase:
https://www.youtube.com/watch?v=d5i_kSJAjq0
Footage and design is half a century old smile

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#217682 - 10/12/16 01:23 PM Re: 230 or 345 kV transmission lines? [Re: Vlado]
annemarie1 Offline
Member

Registered: 03/16/15
Posts: 49
Loc: england
Would they really put something as high as 220Kv on wooden poles surely to get safety clearance you need a metal pylon

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