I was driving down I65 this weekend and went through about a 10 mile
stretch of wind farm in Indiana. And I was wondering how they got all
that power back on the grid. Each one of those windmills has a
generator on top of it I assume. So each generator is generating an
alternating current, and no way in hell are all of those literally
thousands of generators going to be in phase... So I was wondering to
get the generated current back on the main grid efficiently dont they
have to have some kind of master controller to align the phase of all
those generators back to the timing of the main grid and lock it in?
If the phases were all random for those 1,000 windmills wouldn't there
be cancellation of the current flow when you try to pump it back to
the grid individually? Because by probability half the generators
would be out of phase with the other half and simply cancel each
others current flow. Or do they just time each generators phase angle
individually off a small control current from the grid, and let it
feed the grid right there?

Any electricians can shed some light on this?

On Sep 6, 8:59*pm, RickH wrote:
I was driving down I65 this weekend and went through about a 10 mile
stretch of wind farm in Indiana. *And I was wondering how they got all
that power back on the grid. *Each one of those windmills has a
generator on top of it I assume. *So each generator is generating an
alternating current, and no way in hell are all of those literally
thousands of generators going to be in phase... *So I was wondering to
get the generated current back on the main grid efficiently dont they
have to have some kind of master controller to align the phase of all
those generators back to the timing of the main grid and lock it in?
If the phases were all random for those 1,000 windmills wouldn't there
be cancellation of the current flow when you try to pump it back to
the grid individually? *Because by probability half the generators
would be out of phase with the other half and simply cancel each
others current flow. *Or do they just time each generators phase angle
individually off a small control current from the grid, and let it
feed the grid right there?

Any electricians can shed some light on this?

They may be synchronous alternators but are more likely to be
asynchronous. ie, induction motors run at supersynchronous speed as a
generator.

http://en.wikipedia.org/wiki/Asynchronous_generator

They are a cheap solution but rely on synchronous generators elsewhere
to maintain grid integrety

RickH wrote:
I was driving down I65 this weekend and went through about a 10 mile
stretch of wind farm in Indiana. And I was wondering how they got all
that power back on the grid. Each one of those windmills has a
generator on top of it I assume. So each generator is generating an
alternating current, and no way in hell are all of those literally
thousands of generators going to be in phase... So I was wondering to
get the generated current back on the main grid efficiently dont they
have to have some kind of master controller to align the phase of all
those generators back to the timing of the main grid and lock it in?
If the phases were all random for those 1,000 windmills wouldn't there
be cancellation of the current flow when you try to pump it back to
the grid individually? Because by probability half the generators
would be out of phase with the other half and simply cancel each
others current flow. Or do they just time each generators phase angle
individually off a small control current from the grid, and let it
feed the grid right there?

Any electricians can shed some light on this?


there's this from the company that runs that farm:
http://www.horizonwind.com/about/ftk...windmills.aspx

On Sep 6, 9:32*pm, leonard hofstadter wrote:
RickH wrote:
I was driving down I65 this weekend and went through about a 10 mile
stretch of wind farm in Indiana. *And I was wondering how they got all
that power back on the grid. *Each one of those windmills has a
generator on top of it I assume. *So each generator is generating an
alternating current, and no way in hell are all of those literally
thousands of generators going to be in phase... *So I was wondering to
get the generated current back on the main grid efficiently dont they
have to have some kind of master controller to align the phase of all
those generators back to the timing of the main grid and lock it in?
If the phases were all random for those 1,000 windmills wouldn't there
be cancellation of the current flow when you try to pump it back to
the grid individually? *Because by probability half the generators
would be out of phase with the other half and simply cancel each
others current flow. *Or do they just time each generators phase angle
individually off a small control current from the grid, and let it
feed the grid right there?

Any electricians can shed some light on this?

there's this from the company that runs that farm:http://www.horizonwind.com/about/ftk...indmills.aspx-

Oversimplified schoolboy stuff.

On 9/6/2011 2:59 PM, RickH wrote:
I was driving down I65 this weekend and went through about a 10 mile
stretch of wind farm in Indiana. And I was wondering how they got all
that power back on the grid. Each one of those windmills has a
generator on top of it I assume. So each generator is generating an
alternating current, and no way in hell are all of those literally
thousands of generators going to be in phase......

Why not? All the other thousands of generators all over the country are.

Yes, they are in phase when started; the small amount (relatively) of
generation of each generator is effectively locked in by the grid.

In order to "parallel" the 3 phases, each A-B-C phase of the power
source (whether it's 100 watts or 1,000 megawatts, it makes no
difference) has to be in "synchronization" with the A-B-C phases of the
system.

In large units, this used to be done manually by using what's called a
'synch' scope with a rotating arm (representing the phase angle of the 3
phases as one, in relationship to the phase angles of the system. When
they are at "unity", that is the arrow on the meter facing straight up,
the switchyard breaker is closed. Now, such can be done automagically w/
servomechanisms and online measurement.

When the generator goes on grid, the system "grabs", quite literaly, the
generator and the three phase angles move in harmony/synchronization.
The 'speed' of the turbine/generator, whether 1800 RPMs or 3600 RPMs is
then forced driven by the system and not the primary energy source
(wind/steam/whatever). No matter how much more steam (or water as in
hydro) you add, the speed will always stay the same. Which is how power
is increased because the additional input wind force, while not adding
speed, adds torque, which, by increasing the
DC field, increases megawatts.

(Not EE/electrician but NE w/ 30+ yrs working w/ power utilities)

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