Blog HEMAV

HEMAV, drone inspection and maintenance of wind turbines

WHAT IS HEMAV? – DRONE TECHNOLOGY APPLIED TO THE WIND ENERGY SECTOR

HEMAV is a service company specialising in performing inspections for the power sector, covering generation, transmission and distribution activities. The company benefits from a multidisciplinary team of engineers qualified to process data and images, as well as their capture through the use of drone technology.

HEMAV is currently undertaking wind turbine blade inspections, achieving an improved quality of information compared to using the same optical tools at ground level, as the drone provides a better perspective for image capture. Although this advantage is obvious for the inspection of mid-range 1.3 MV turbines; for new wind turbine models of 3 and 5 MV with nacelle heights reaching 120 metres to even 147 meters, this technology becomes essential, as taking quality images from ground level is increasingly complicated.

Lastly, compared to inspections made by means of vertical work, drone inspections offer a key safety element as inspectors do not have to be exposed to the risks inherent to working at such heights.

 DRONE TECHNOLOGY APPLIED TO LIFETIME EXTEN

Today’s visual inspections do not provide enough information on the internal layers of the housings or the blade structure. This information, however, is vital in order to characterise the status of the blades within the context of lifetime extension. Thanks to passive thermal imaging and internal monitoring technologies. a characterisation of the actual status of the blade deterioration can be carried out to support the decision-making process.

Passive thermal imaging is an inspection technique that provides a blade analysis similar to that achieved by thermographic inspections performed in the workshop following manufacture or repair. The difference lies in the fact that instead of using an air-jet type method of thermal excitation, it uses the heat of the sun itself. This technique integrated into a drone platform is able to carry out the assessment with no need to take down the blade or transport it to a facility.

As a result, the status of the internal layers of the housings can be assessed and defects identified that are not revealed during the visual inspection, such as delamination between the structural ribs and the housings and, in general, any defect appearing in areas that have a material m¡continuity with the housing and at a depth of no more than 5 cm from the surface. Blade monitoring provides information on the status of its  internal structure. HEMAV uses specific indoor flight drones that are currently used to inspect confined spaces in a range of environments including power generation boilers and hydraulic conduits. This tool is able to capture elements inside the blade and perform a visual inspection that would otherwise be impossible or extremely difficult. The inspection takes place without dismantling the blade, as the monitoring drone accesses the blade directly from the hub and passes through the interior via gaps in the ribs.

Although this machine is fairly small (40 cm in diameter), there is a size limitation to accessing some parts of the blade and, depending on the wind turbine, only one or two thirds of the length of the blade are inspected, as the most accessible area is the most critical, being adjacent to the blade joint. However, HEMAV continues to innovate to develop new technologies. Its current focus is on miniaturising this type of tool, given that internal monitoring is able to identify internal structural defects, such as cracks and flexing inside the housings

Thanks to the combination of passive thermal imaging and internal monitoring undertaken by HEMAV, a very accurate result is obtained regarding the status of the blades to support decisions on their lifetime extension.

Leave a Comment

Your email won't be published.

Main Headquarters

Madrid

Edificio Ibercenter

Plaza Carlos Trías Bertrán 4 28020 Madrid

(+34) 914 184 546

info@hemav.com

Barcelona

ESA (European Space Agency) Edificio RDIT

Esteve Terradas 1 08860 Castelldefels

(+34) 932 202 063

info@hemav.com