Throughout the world, thermal imaging cameras are used for the inspection of electrical and mechanical equipment. The thermal data which they record prevents dangerous accidents and expensive downtimes. All of the relevant components of a wind turbine can be examined with the aid of a thermal imaging camera.

Electricity generated by wind energy plant is now the most widespread form of renewable energy. Every year, new wind energy plants are being installed throughout Europe and in many other countries in the world. All of these win turbines need to be monitored and maintained. Thermal imaging cameras can take an important role for the preventative maintenance of wind energy plant.
Many different electrical and mechanical components are installed in modern wind energy plants. As with any equipment, these components are subject to wear and tear and can fail. This can not only result in expensive downtimes, but also dangerous accidents.
The gear units and brakes in the system ensure that the rotor blades do not rotate too fast. If any of these components fails, the turbine may rotate at many times its normal speed. Forces may act on the rotor blades, which are many times greater than those for which they are designed. In such cases, the tips of the rotor blades may reach a speed of several hundred kilometres per hour. If a blade, or part of a blade suddenly detaches from the rotor and is thrown off, it has an enormous kinetic energy and a very large torque. This can result in potentially lethal accidents.
There are many examples in which large sections of broken blades have been found 10 or more kilometres from the turbine from which they originated. Such accidents can be prevented by regular inspections with thermal imaging cameras.

The entire system at a glance

In general, both electrical and mechanical components heat up before they fail. This temperature increase can be detected with the aid of thermal imaging cameras before failure occurs.
The hot spots appear sharp and clear on the thermal image. Whereas other technologies only provide information which shows that there may be a problem with the machine as a whole, thermal imaging technology helps the user to actually see the problem. It shows precisely which component is causing the problem.
Thermal imaging makes signs of wear on bearings, shafts, gear units and brakes visible. Therefore components can be repaired or replaced before faults occur. Thermal imaging cameras also provide valuable information about electrical components such as transformers, plug connectors, wind tracking units etc. Thermal imaging is therefore the only method with which all the electrical and mechanical components of the wind energy plant and its associated electrical system can be examined.

An ideal tool with a wide range of applications

Wind energy plant maintenance teams throughout the world rely on thermal imaging cameras. The design of the camera is decisive for its user-friendliness on site. Flir cameras are very compact and ergonomically designed, as well as being easy to use. Users appreciate these characteristics if they have to climb more than 10 m in order to reach the wind turbine.
A further important factor is the lens which is used. Optionally, 45° and 90° wide-angle lenses are available. With these, users can view large sections of the plant at a glance, even if they are relatively close to the object. This is a great advantage in view of the fact that at the top of the wind energy unit, the viewing distance cannot be increased by simply stepping back.
However, thermal imaging cameras can do far more than providing images for preventative maintenance. With the aid of cooled cameras, damage to the composite materials of rotor blades can be detected. So-called pulsed thermography is often used to detect delamination and hairline cracks in composite materials. The composite material is excited with the aid of a lamp. The thermal imaging camera is then used to monitor the distribution of heat within the material. Differences in the rate at which parts of the rotor blade heat up or cool down indicate damage.
As has already been mentioned, damaged rotor blades can cause dangerous or even lethal situations. These can be prevented with the use of thermal imaging cameras. These can show which rotor blades need to be replaced before failures or accidents occur.