Installation

4. WIND TURBINE INSTALLATION

wind measurement

license and permissions

The next step on our path is a little more tedious. A technical project will be carried out, where the most suitable wind turbines for the studied terrain will be determined, as well as the desired location. At the same time, we will start the license applications, as well as the procedures for the acquisition or lease of the land where we want to settle, in case they are not owned by the developer.

One of the most important procedures when obtaining a license is the environmental impact study, which will detail to what extent our operations will affect the animal and plant ecosystem in the area. In addition, complementary installations to our wind farm, such as high-voltage electricity distribution lines, or the necessary electrical substations, will start in parallel projects.

All the formalities necessary to obtain the final license can take several years, so applications for licenses and environmental impact are usually launched almost at the same time as local measurements.

civil works

Once the license is obtained and the availability of the land is assured, the preparatory work begins. Roads will be prepared in the chosen terrain, to allow the arrival of components and the cranes that will install them. Due to the height increase of wind turbines, already reaching 200 meter, the vials for the cranes must in some cases exceed 15 meters in width.

Likewise, it is very important to review and modify the access roads to the park and even build alternative routes to the existing ones, even if temporarily, for example, to be able to avoid crossing population centers.

The civil works of a wind farm include the following infrastructures:

• Access roads to the site.

• Internal roads of the site.

• Wind turbine foundations.

• Platforms for gathering materials and positioning of cranes at the foot of each wind turbine.

• High voltage underground power lines and communications between electrical substation and wind turbines.

• High voltage overhead lines for evacuation of the energy produced.

turbine installation

Once we have the land ready for installation, and we have opened the necessary roads for the arrival of materials, it is when we can start to collect the different components, which will have been purchased months before (the delivery times of components, being so specific and expensive, might be very wide). Not only road widths, but also maximum grades and turning radii in corners are key factors.

Normally, as soon as we have the zone ready, and the foundation has passed the controls (it takes 28 days for the concrete to acquire 100% of its hardness, and laboratory tests are carried out several times to ensure that it has the required resistance), we are ready to receive components.

The first component that is usually assembled is the crane. Due to the height we need, the largest self-propelled cranes have dimensions that don't allow them to travel by road, only on the internal roads of the site, and to move from one wind farm to another, or even between the different areas in the same site if it is very extensive, they must be assembled and disassembled for transport.

Due to its size, the tower is supplied in 4 or 5 sections that will be assembled on the platform built next to the foundation. Then, the nacelle will be mounted, and then the rotor. Because, especially in onshore installations, the higher we go, the more stable and powerful the winds are, the technology looks for taller and more powerful turbines.

In some cases, the rotor is mounted on the ground and fully lifted, while in others the hub is first hoisted and then the blades are mounted one by one, horizontally (at 3 o'clock) or vertically ( at 6 o'clock).

grid evacuation for the produced energy

As we have mentioned, a high voltage electrical line, normally underground, will connect the different wind turbines to each other. It is made underground taking advantage of the construction of the roads (normally one of the ditches is used) and to minimize the visual impact.

Once all the mills in our park have been connected, an evacuation line is necessary. Wind turbines will normally supply electricity between 10,000 and 40,000 Volts. Depending on the distance to the existing electrical network, it is possible that a transformer substation is installed within the same wind farm, to further increase the voltage, up to 132,000V, if the distance is very long.

At these levels, the high-voltage lines are to be built overhead, with metal lattice towers.

maintenance and supervision

Wind turbines are designed for a life time of about 20 years. We can find many cases of wind turbines that are much older and still working, but their lifetime is considered to be that. During the life of the wind farm, the turbines will be remotely supervised (a control center informs and allows the remote operation of the wind turbines), and the wind turbine will only be attended by maintenance technicians.

The maintenance of a wind turbine is classified into:

• Preventive: components that have an ending lifetime, change of oils, lubrication, etc. Low or no production times are planned to send the technicians to the site.

• Predictive: by means of sensors, we can anticipate failures that are not critical, that is, the wind turbine can continue to operate, but in the next stop due to Preventive Maintenance, we must carry out the repair to avoid a failure of the turbine when it is in full production.

• Corrective: Performed when a critical component unexpectedly fails and the turbine cannot continue to operate. It can be from an alarm that is considered critical for the security system (failure to read a temperature, for example) to the change of a large component, such as a gearbox.

Due to the high cost of wind turbines and the interest that they are producing as long as possible, the availability factor (that is, the time the turbine will run smoothly when the wind blows) is critical. The best manufacturers have availability factors of more than 98%.

go to conclusion

home