transmission voltages

[lando]

When referring to transmission voltage, 69,115kv,230kv. Are you talking phase to phase or phase to ground? and if one is talking phase to phase , what are the voltages phase to ground. Any reference to any posted info would be appreciated.

[Edge]

Transmission and most but not all sub transmission voltages are Delta so they are phase to phase.... usually its safe to say that 69kv and up are delta...so phase to phase...

theres some 42 and 34.5 out there thats subtrans and y in nature so it has a reference to ground and so it has a phase to ground voltage 34.5 being 19.9 and such....

gets interesting from 69 up cuz most of the delta is corner grounded... and thats another issue...

I read your question bub... but not sure exactly what you are asking seems like its more...

for what it's worth...

Edge

[US & CA Tramp]

Transmission and most but not all sub transmission voltages are Delta so they are phase to phase.... usually its safe to say that 69kv and up are delta...so phase to phase...

theres some 42 and 34.5 out there thats subtrans and y in nature so it has a reference to ground and so it has a phase to ground voltage 34.5 being 19.9 and such....

gets interesting from 69 up cuz most of the delta is corner grounded... and thats another issue...

I read your question bub... but not sure exactly what you are asking seems like its more...

for what it's worth...
Edge
According to IEEE and OSHA, all voltages are measured phase to phase in distribution and transmission. Also not all but most sub transmission and transmission systems are wye in configuration. They may look like Delta but when you go back to the source you will find they are configured in a Wye, and rely on the earth for return. Transmission stations will have large ground mats buried, and sub transmission stations will sometimes have a grounding transformer for ground reference.

To get the phase to ground voltage, divide the phase to phase voltage by pie. Look it up to be sure but I think pie is 3.14.

The last point for information is in most locations, any line under 69KV phase to phase is considered a distribution circuit.

[wtdoor67]

Always thought the majority of them were Wye. Never saw anyone slap a ground on them like a regular delta. I've seen em go to ground on trouble. Big blaze and operated the breaker.

Pie or Pi? Whoa don't let Swimp get ahold of that. You are talking about the sq. root of 3 aren't you? 1.73 eh?

Yep, always measured and spoken of in phase to phase terminology. Course in distribution since it's used some in single phase mode folks sometimes speak of it in phase to ground voltages.

[wtdoor67]

Actually, transformers on high-voltage transmission systems can be wye-delta, wye-wye, or they can be wye-connected autotransformers. The answer is usually a matter of economics.

The transmission system almost always requires that the transformer winding be connected in wye - this is because the transformer must be a 'zero sequence source'. That means that the transformer is capable of supplying current to single-line-to-ground faults on the transmission system, and it also able to sustain near normal phase-to-neutral voltages on unfaulted phases of the transmission system.

Delta-wye transformers would typically be used to connect generators to the transmission system - the delta winding adjacent to the generator, and the wye on the transmission side. This meets the criteria stated above for the transmission system while isolating the generator grounding from the transmission system grounding.

Delta-wye transformers might also be used to interconnect different transmission voltages. However, the issue is that the criteria stated above must be satisfied on all transmission systems, and the delta winding would not meet that requirement.

Delta-wye transformers would be the preferred arrangement when feeding substations from a transmission system. In this application, the delta would be on the transmission side because, and the wye would be on the substation side. A key requirement is that the presumption is that the normal direction of power flow would be from the transmission system to the substation.

[Pootnaigle]

All the transmission voltages I have dealt with are generated wye....... However when they are connected to the sub station transformers they are connected delta. Ive never seen a sub station transformer with more than 3 bushings on the primary side, I aint gonna say there aint none but I never saw one.

[Edge]

yeah maybe I should have been more specific...

'door hit it on the head with a few of his posts

one is the phase to ground 1.73 mutiply that and you get your phase to phase voltage...

most of the ac transmisson voltages I have worked were in fact generated wye but steped up to delta and usually corner grounded...

most of the subtransmissoin voltages I've worked have been wye... the most common being 34.5

hopefully the op can tell it's different everywhere and depends on where your working the best thing you can do is look at the plat on the sub tub and that will tell you exactly whats going on

for what it's worth...

Edge

[lewy]

We always refer to our voltages phase to phase.
The highest voltage we work on is 44 & we call it a sub transmission it is a wye, but there is no neutral like said earlier, but when we hook it up the transformers actually say delta on the 44 kv side.

[Edge]

you cats may need to do some research.... I may be wrong but I thought all US transmission ...especially 765 and 500 was delta to delta... there is a required grounded connection from the generation to the transmission line but thats at the station grid and goes to the static... thats why we've had so many static var jobs in the past few years... another story I know...


I might be wrong but ... well...

prove it...

Bill

[Pootnaigle]

If the transmission lines were delta one phase could be grounded with no ill effects.......... That dont happen round here.

[Edge]

If the transmission lines were delta one phase could be grounded with no ill effects.......... That dont happen round here.

Transmissions a deterrent beast Poot... your talking about miles and miles of line ... you got induction and all that..... makes grounding a fugging night mare....

tell me more...

Bill

[neil macgregor]

different voltage over here
UK 240v 11kv 33kv 66kv 132kv 275kv 450kv

ireland 240v 10/20kv 38kv 110kv 220kv

[Highplains Drifter]

different voltage over here
UK 240v 11kv 33kv 66kv 132kv 275kv 450kv

ireland 240v 10/20kv 38kv 110kv 220kv

Thanks neil, I have been trying to get someone that was over seas for years to tell us the voltages they work with and they never tell us.

[HIVOLTS]

44kv and up is considered transmission, and yes that's phase to phase. Transmission lines don't have a neutral, they have a static for lightning protection and now they run fiber inside that. Substation transformers are generally hooked up Delta on the high side, Wye on the low.

[wtdoor67]

I thought we were trying to establish what the typical connections of most transmission were. Is the 138 KV, 161 KV etc in your area connected Wye or Delta? That is my curiosity. I realize a lot of them are connected Delta on the high side in a sub. etc. but that doesn't mean the line is a Delta. A Wye can be connected Delta into a bank etc. Some substation transformers may only have 3 bushings on the source hi side but internally they are connected delta with only 3 entrance bushings. Looking at the label diagram on the sub pot might tell you.

[neil macgregor]

Thanks neil, I have been trying to get someone that was over seas for years to tell us the voltages they work with and they never tell us.

the voltage in ireland is the same as the rest of europe
the UK voltage is a bit bigger feck knows why
the 10/20 kv refers to the upgraded 10 kv system
some of the trafo,s are 10kv some are 20kv
(not on the same line)they are hoping to upgrade the whole
system to 20kv

[BigClive]

the voltage in ireland is the same as the rest of europe
the UK voltage is a bit bigger feck knows why
the 10/20 kv refers to the upgraded 10 kv system
some of the trafo,s are 10kv some are 20kv
(not on the same line)they are hoping to upgrade the whole
system to 20kv

It's because we invented electricity and everything else is just an inferior copy. :p

Actually I just assumed that Ireland was 11kV etc like the UK. Is that the whole of Ireland or just southern?

So what's the Isle of Man then? 11kV?

[topgroove]

It's because we invented electricity and everything else is just an inferior copy. :p

Actually I just assumed that Ireland was 11kV etc like the UK. Is that the whole of Ireland or just southern?

So what's the Isle of Man then? 11kV? Many facinating inventions came from Scotland. The first electric drill, The first comercial hydro electric stations, The first to have a working tidal wave generation system ( enough to power over 400 homes) Though I don't think we can say Scotland invented electricity.

http://resources.schoolscience.co.uk/britishenergy/14-16/index.html

[Boomer gone soft]

Groovster,

They DID invent golf.....that gives them claim by proxy to all things cool forevermore!:D

[topgroove]

Groovster,

They DID invent golf.....that gives them claim by proxy to all things cool forevermore!:D Good point! They also make some damn fine booze:D

[bobelectric]

I doubt that voltage at that level would be "corner grounded" .

[neil macgregor]

It's because we invented electricity and everything else is just an inferior copy. :p

Actually I just assumed that Ireland was 11kV etc like the UK. Is that the whole of Ireland or just southern?

So what's the Isle of Man then? 11kV?

just the south clive the IOM is also 11kv by the way this might intrest you

http://www.independent.ie/business/irish/esb-completes-deal-to-buy-nie-2469582.html