how do megawatt Solar farms prevent voltage loss in long wire runs?

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

rollandelliott wrote: »

how do megawatt Solar farms prevent voltage loss in long wire runs?
Looks like some wire runs are a few football fields long!
Just curious!

With AC runs, sometimes with big wire and parallel runs, sometimes with step up/step down transformers, depending on the economics of the situation and the length of the run. Keeping the inverters and combiners as near as possible to the arrays helps with the DC voltage drop, as well as running big wire from the combiners to the inverters.

Typically the specs for voltage drop are more restrictive on the AC side, since voltage drop on the AC line results in voltage rise at the inverter terminals and can kick the inverter off line.

There is always some loss due to voltage drop. There is no way around it.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

I think in many cases the true answer is...

They don't.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

They are called Big Thick Aluminum Buss Bars.

FH

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

feedhorn wrote: »

They are called Big Thick Aluminum Buss Bars.

FH

even those large buses have resistance and if some will look i had already said, "technically, it doesn't prevent voltage losses" in wire runs. any resistance will have a predisposed v drop with a specified current going through it.

for example, if you run 12v with 10a through a 20ft long piece of #10 cu wire it will drop .255v at 90 degrees c for a percentage of 2.123%. with everything the same except for the voltage which we will put to 24v for our demonstration we see the same .255v being dropped, but because it is 24v being referenced to, the percentage is now 1.061%. do note that doubling the voltage with the same current will double the wattage flowing through the wires. no v drop is prevented by a large solar farm or even by higher voltage if the current and wire size is held to the same values. if it is a question of a set wattage with raised voltages then that will reduce the current flowing and reduce not only the %, but it will reduce the actual v drop itself. all wires, connectors, etc. have resistance and as such will always have a v drop no matter how large or small. when one ventures into the land of 0 ohms resistance you have entered a mythical area that does not exist except in theory and even then that would create a circumstance of infinite current with 0 volts which for many of us know that means there is no power because v x i = p.:roll:

what large generation points do is raise the voltage while keeping the same current in a wire which in effect allows more power to be transferred through that same wire over the same distance. power utilities do take advantage of this so they do not need to change out the wires already present to carry more power over them and those wires would be expensive to change out in order to up the capacity the same amount as upping the voltage has allowed.

so ends this electrical lesson. case closed.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

ggunn wrote: »

What do N2 filled transmission lines do? I assume that this is to exclude O2, but why? How does it reduce line loss?

the only thing i can think that might do is preserve the wire so that no oxidation takes place to degrade the wire. oxidation would lead to higher resistance.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

mike90045 wrote: »

Filled with liquid nitrogen ?

There are a few areas where some superconducting power lines are installed.

nobody said liquid nitrogen as they would trap the gas into the gap areas that show up in the wire. i've often wondered the difficulty in doing this and how they preserve it inside of there once it's there.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

niel wrote: »

the only thing i can think that might do is preserve the wire so that no oxidation takes place to degrade the wire. oxidation would lead to higher resistance.

But copper does not oxidize readily in air and I believe that when it does it forms a thin impervious layer that prevents further oxidation. I don't think that's it.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

niel wrote: »

i'm guessing as i use standard wires. btw, copper does eventually get eaten through by oxidation and any oxidation that is there has a high resistance to it electrically.

So far, Google has yielded nothing. I am pretty sure I have seen N2 cannisters in substations, though. Copper gets eaten by corrosion from exposure to some things, but air isn't one of them. Other than turning brown on the surface, there are plenty of copper coins that have been around a very long time with no ill effects.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

niel wrote: »

i never said anything about air.

OK, but what other function could nitrogen serve besides displacing air? You did mention oxidation; what source of oxygen other than air are copper conductors likely to be exposed to?

I'm not trying to be combative, I'm just trying to reason it out.

Re: how do megawatt Solar farms prevent voltage loss in long wire runs?

Cariboocoot wrote: »

I've got to refrain from starting these Easter egg hunts; they always seem to lead to arguments.

Bill had the answer at post #14.

Now, what about the alien time warp technology?

yes, stop that as somebody is bound to complain you are picking on watch making in another far off country and then somebody will assume we are talking about their great uncle hands solo (yep, i went there) who fixed watches.:p:p:roll: