How are wind farms connected to the grid
How are wind farms connected to the grid
(OP)
I am curious how windfarms are connected to the grid, and what type of equipment is used to transmit power between the wind turbine and the connection to the grid (transformers, switches, etc....) Does anyone know of a good reference to learn what type of distribution equipment is involved with connecting the wind farm to the grid.
I'm also curious about how solar fields are connected as well.






RE: How are wind farms connected to the grid
2. Voltage is stepped up at the wind turbine to a collector system, usually 34.5 kV or so.
3. A number of collector systems are gathered and that power is then transformed at a transmission station (115, 230, or 500 kV in the western US).
4. Done
So, to summarize, wires and transformers, just like any other generator. Really nothing too special in getting renewables up on the grid.
RE: How are wind farms connected to the grid
Thanks for the information.
What are the collector systems you mention made up of? Are these single units, or are these several units involved in thsese collector systems?
At the transmission stations, how is the wind farm frequency synced with the grid? Does it convert it to DC first?
RE: How are wind farms connected to the grid
Small grid connected systems tend to be most cost effective with DC because they can generate at a very wide range of wind speeds, but they need an inverter to create AC. That inverter synchs up with the grid. DC becomes impractical above a certain size (5kW, 10kW maybe?) because they either have too much maintenance (brushes and commutators) or they become too expensive (permanent magnet).
AC Induction generators are basically just AC induction motors which are run up over speed by the turbine so that they become generators. Induction generators range from 5kW to megawatt sizes. The connection to the grid itself is what regulates the output frequency, but then mechanical speed control of the turbine is necessary so as to not create too much negative torque. So you forgo the brush / commutator electrical maintenance and add in mechanical maintenance for the speed control systems. Depending on size, these will feed a local transformer to step up to the grid voltage where they are connecting, or really large ones may actually generate at the grid voltage.
AC Synchronous generators are used when there is a possibility of having to run "off grid", because they can be externally excited (whereas the Induction machines need the grid for winding excitation). They can also be run at much slower speeds, reducing the amount of speed control necessary. Other than that, they are connected to the grid in the same way as Induction generators. They are not as popular because they are more expensive, but if you want "island mode" generation (off-grid) then they are really the only choice other than DC.
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RE: How are wind farms connected to the grid
Permanent magnet synchronous generators are starting to become more common. Most of these do not operate at synchronous speed, but rather supply their output via a AC/DC/AC converter. See thread626-272241: direct drive wind turbines?
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.