As people and businesses become more environmentally aware and want to reduce their carbon footprint, the switch to renewable energy grows apace. To meet this demand the number and scale of wind farms are increasing, and so too is the requirement to ensure they are operating effectively.
Operating over 35 metres (114 feet) from the ground and with three blades each measuring over 20 metres (65 feet), a wind turbine is not the easiest piece of equipment to inspect.
Wind turbines are situated on hillsides in a fairly harsh environment, continually exposed to the elements. The scale of the technology involved, also means that it is important to ensuring that all the components are operating the way they should and are structurally sound.
Using different technologies and techniques, including video probes and non-destructive testing, Inspectahire can survey every part of a wind turbine; from the concrete base on which it stands, to the tip of its blades and all the mechanics in between. Each survey undertaken is carried out in a way which minimises the risk to the inspector and the time involved in the turbine being out of operation.
The Tower
The tower is exposed the weather, including gale force winds. Constructed out of welded steel, each section is bolted together on the inside.
An inspection of the outside of the tower examines the integrity of the welds and also details any possible damage. A remote access crawler attaches to it with the use of magnets, which allows it to travel vertically and horizontally on the structure to carry out an inspection and feed information back to the inspector on the ground. This eliminates the need for costly scaffolding or rope access.
Internally, visual inspections are carried out to identify any damage to the bolts or flanges. Damage to these can impact on the safety of the turbine.
The Nacelle
The nacelle is one of the most important parts and houses much of the mechanics of the turbine, including the gearbox, generator, brake, controller and yaw mechanism. If each of these items did not operate correctly then the turbine could fail to generate electricity.
Inspections are carried out with video probes to ensure that there is no damage, and no debris has built up around the moving parts. If the yaw mechanism is damaged then the turbine may not be able to turn its blades against the wind, which could result in greater damage.
As a turbine rotates, heat is generated in the nacelle. If debris is present, this could ignite, in a worst case scenario. Video probes allow the inspector to see parts of the mechanism which cannot be visually inspected. Debris can be removed using special retrieval tools.
The Blades
The blades are some of the hardest working parts of a wind turbine. They are exposed to the weather, rotate at 10 – 22 rotations per minute and are designed to endure more than 120,000 operating hours. Being made of fibreglass and weighing around 12 tonnes each, there is a need to ensure they are structurally safe.
Thermographic cameras can be used to identify areas of the blade which may be delaminating, as it detects variances in the heat of the blade structure. Inspection of the blades can also be carried out using a telescopic mast and a zoom camera which can examine the blade in detail.
