How does wind power reach our homes?
In previous articles, we have explained the basic principles pertaining to wind power and the parts that make up a wind turbine. Today, we will investigate a little further and tell you how electricity is generated from this source, and how it reaches our homes. Here we go!
As you will remember reading in our previous article, wind power is produced when changes in temperature occur in air masses in the atmosphere. This causes wind to appear whose force moves the wind turbines that have the task of generating wind power.
“The generator is responsible for producing electricity form wind power. After passing through a transformer and a wind farm substation, it reaches the grid, and in this way gets to our homes.
But just how is electricity generated, and how does it get to our homes? Specifically, the wind speed should exceed 4 m/s as at this point, it is able to move the wind turbine’s blades and turn the rotor. Inside we find a mechanical system that consists of a main axis and a gear system called a multiplier. These convert the revolutions to a higher speed onto another output axle which then moves the generator that produces the electricity.
So how is mechanical power turned into wind power? The answer lies in the form of an electrical generator. There are two kinds of generators: ones that are directly connected to the grid (synchronous generators and doubly fed induction generators or DFIG), and those that are connected to high-powered electronic equipment, which in turn, are connected to the grid (full converters).
Electricity leaves the generator at a low voltage (690 V). To keep electricity losses to a minimum, it is sent through a transformer which changes it to a higher voltage, normally between 20-30 kV, and this enables it to reach the substation on a medium voltage network. This is normally done underground by means of power cables and it is known as the wind farm collecting system.
Once in the wind farm substation and with the help of a high voltage line, the electricity is evacuated to a connecting substation, and from there the electricity transport network takes over. This consists of high voltage lines that, as the name suggests, transport the power over long distances, as well as the distribution infrastructures, and so the electric power finally reaches our homes.
“Wind farms are located a long way from cities in places with large wind resources.
Generally, wind farms are located a long way from cities in areas with the best wind resources, thereby ensuring the energy is usually evacuated at a high voltage (≥220kV). It is then connected to its distribution network by means of a connecting substation or a nearby electrical substation.
The requirements affecting the compliance with the conditions of the grid are becoming increasingly more stringent. This is why the quality of grid power from wind turbines is also increasing. According to the grid code which specifies technical requirements for connection, operations with reactive input are required with varying voltage and frequency, in addition to being able to withstand voltage dips.
At the Campo Palomas wind farm that Abengoa has built in Uruguay, we find wind turbines with blades that are 50 meters in length, designed to produce 9,000 MWh each year. This is sufficient power to supply 2,100 homes. When we compare these structures with the first 30 kW turbines that were built 30 years ago, the innovative systems we currently find generate 360 times more power each year.