Deutsche Windtechnik Using Drones for Large-Scale Periodic Blade Inspections at Butendiek Offshore Wind Farm

June 22, 2023, by Adrijana Buljan

Deutsche Windtechnik performed the periodic inspection of the rotor blades at the German Butendiek offshore wind farm using automated drones at the beginning of this month. According to the company, it is among the first to carry out a large-scale offshore wind inspection campaign using automated drone technology.

The work included the inspection of the rotor blades of Siemens Gamesa SWT 3.6-120 wind turbines, 80 of which make up the 288 MW offshore wind farm.

The drone used for inspection was DJI M300 RTK, which had previously been upgraded with a customised camera and sensor technology.

“Using our drone at the Butendiek offshore wind farm, we were able to verify that a drone can save a significant amount of time compared to the conventional rope access technique. This has significantly reduced the downtimes of the turbines during inspections”, said Jens Landwehr, Managing Director of the Offshore Unit at Deutsche Windtechnik.

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This approach was made possible by advancements in drone technology, as well as new specifications from the German Federal Maritime and Hydrographic Agency (BSH), which allow remote optical inspection procedures in addition to rope access operations, Deutsche Windtechnik says.

The entire inspection procedure is based on the new BSH specification called “Requirements for Rotor Blade Inspections Using Remote Optical Inspection Procedures & Clarification of the Inspection Obligation for the Interior of the Rotor Blade and the Lightning Protection System”.

According to the ndew specification, 50 per cent of an offshore wind farm’s turbines can be inspected using a drone each year. After a detailed review of the documented drone footage by the inspection experts, 8 per cent of these turbines are additionally inspected using rope access technology.

“Using drone technology to inspect rotor blades enables us to get a more complete picture of the entire exterior of the rotor blade compared to conventional rope access technology. In addition, the ability to determine the exact location of possible damage as well as the support provided by the software help to precisely document the development of the damage, and this can be very helpful for the assessment”, said Tobias Bläs, Team Lead Rotor Blades at Deutsche Windtechnik.

“The economic advantages due to the shorter time required for the procedure and the resulting shorter downtimes make this method a suitable alternative to rope access technology in many cases”.

The 288 MW Butendiek offshore wind farm, operational since 2015, located some 32 kilometres west of the island of Sylt.

At the beginning of this year, Deutsche Windtechnik also won a tender for the installation of an Aircraft Detection Light System (ADLS) on the offshore wind farm, after equipping the Nordergründe offshore wind farm with the same system last year.