Wind Farm

[handy10]

On the way from Indianapolis to Chicago, there is a huge wind turbine farm. I suppose there must be a thousand turbines. The strange thing is that there is not much in the way of transmission lines. Since one turbine can produce 1.5 MW or more, how is all of that power moved?

 

[Van G.]

I seen that also while traveling out in west texas, hundreds of those things but no visible major transmission lines nearby. All these things are out in crop fields. Surely they can't be doing service lateral to a central location but they must be.

 

[rt66electric]

speed change

speed change

on a another note:
I noticed that while driving by on a day a calm day, then driving the other direction a stormy/windy day. The rotation speeds stayed about the same??

 

[ggunn]

on a another note:
I noticed that while driving by on a day a calm day, then driving the other direction a stormy/windy day. The rotation speeds stayed about the same??

Many wind turbines have the ability to change the angle of attack of the blades so that they turn the same speed in different velocity wind.

 

[GeorgeB]

on a another note:
I noticed that while driving by on a day a calm day, then driving the other direction a stormy/windy day. The rotation speeds stayed about the same??

A steam turbine also turns the same speed whether at 0.001% or 100% (although operation isn't usually practical below perhaps 25%). Hydroelectric turbines ... same thing. These are synchronous machines and generate 60Hz by operating at some speed 3600/n rpm.

I understand that some smaller wind turbines do operate at varying speeds. They will likely rectify and use an inverter to get AC. I don't know relative advantages.

 

[ggunn]

A steam turbine also turns the same speed whether at 0.001% or 100% (although operation isn't usually practical below perhaps 25%). Hydroelectric turbines ... same thing. These are synchronous machines and generate 60Hz by operating at some speed 3600/n rpm.

I understand that some smaller wind turbines do operate at varying speeds. They will likely rectify and use an inverter to get AC. I don't know relative advantages.

Some wind turbines have constant velocity output transmissions, too.

 

[kingpb]

On the way from Indianapolis to Chicago, there is a huge wind turbine farm. I suppose there must be a thousand turbines. The strange thing is that there is not much in the way of transmission lines. Since one turbine can produce 1.5 MW or more, how is all of that power moved?

1.5MW at 4.16kV is only around 200A, so the higher the voltage the smaller the cable.

But if they are truly that size, and 1000 in number, somewhere there is a reasonably sized substation and switchyard.

 

[jim dungar]

At the base of most turbines, is a 'step up' transformer.
The last ones several I dealt with stepped the voltage up to 34.5kV which was then sent 'underground' several miles to a switchyard for step up to the utility voltage of 138kV.

 

[rcwilson]

Newer units have the 34.5 kV transformer on top the tower. The MV cable runs down the tower and then underground, daisy chaining power from turbine to turbine out to the intertie substation.

Many turbine generators are double fed machines with a wound rotor wired out tthrough brushes to a modifed variable speed drive. 60 Hz goes on the stator and the rotor turns at varying speeds like a wound rotor motor. Instead of resistors burning up energy the controller converts it to 60 Hz like a VFD in reverse. This allows matching wind speed and power output.

 

[mpross]

Wind Farms

Wind Farms

...a lot depends on the manufacturer of the wind turbine when talking about the actual generator/converter topology. It seems that GE has a patent on many of the controls associated with the doubly-fed machines. some of the doubly-fed machines can operate with slip being +/- 30%. Some machines are limited to 1% slip.

design of the substation can be tricky as you have to comply with an interconnection agreement which usually has strict requirements on voltage and power factor at the point of interconnection, which can be miles away from the site. shunt capacitors are used many times, and even reactors are used to limit fault currents at the 34.5 kV substation bus. sometimes harmonics can be an issue and this may require a tuned filter.

I have found the most challenging thing about wind parks is the timeline of the project! these projects can really move when the owner/investor has the right market signals/timing!

ciao,
matt

 

[Van G.]

Newer units have the 34.5 kV transformer on top the tower. The MV cable runs down the tower and then underground, daisy chaining power from turbine to turbine out to the intertie substation.

fascinating and does explain why no Distribution lines.

I work near a major highway coming up out of Houston and these http://www.suzlon.com/ go by here. They park across the street overnight and I was able to look them over. The turbine is really huge up close.

 

[mpross]

transformer

transformer

the majority of the turbines have the transformer at the base still... you dont see the dist. system since it is underground. there are a few turbines manufacturer's that have a 34.5 / 0.69 kV dry-type transformer up tower. i have worked with Vestas, Mitsubishi, Suzlon, GE, REpower, Gamesa, and have seen Clipper. So far the only machines that i have seen to have them up in the tower are the Mitsubishi machines.

here is a good link to show what is up tower...
http://www.mhi.co.jp/en/products/detail/products.html