Inspection of a Wind Blade Using a Videoscope

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Background

Wind power generation has spread mainly in Europe since the latter part of the 20th century as an alternative energy source to fossil fuels with little environmental burden. In the 21st century, it has spread across the world largely due to the rapid growth of the Chinese economy. Wind power generation has advantages such as using inexhaustible natural energy, releasing little carbon dioxide during power generation, and a lower construction cost and a shorter construction period than other power generating facilities. Furthermore, unlike photovoltaic power generation, it also has the advantage of being available for generation night and day. Therefore, it is expected that its adoption will be promoted.
On the other hand, challenges include: avoiding unstable supply due to dependence on wind force, difficulty in securing a large generation capacity, and reducing the utilization rate (decreased operating time) due to failure or accident.

Challenges and Solutions

As shown in the figure below, a wind power generation system consists of blades, a tower (supporting column), and a nacelle (gearbox and generator). For turbine blades with length exceeding 40 m, quality inspection using a videoscope is conducted when they are manufactured. For inspection of the bonded part of the blade trailing edge, the inspector can advance in a space to the middle of the blade. However, as the inspector approaches the end of the blade, the space becomes narrower so that the inspector can no longer advance. With IPLEX, a small and lightweight industrial videoscope, the inspector can bring the videoscope to the middle of the blade, and then feed it to the end of the blade, enabling the inspector to perform visual inspection.
Visual inspection using the industrial videoscope plays an active role also in the maintenance of the blade. The videoscope is used for inspecting the drainage hole at the blade end, checking the bonded part inside the blade, and checking the hub section at the blade root. If the drainage hole is blocked, the water inside the blade may be rapidly evaporated in case of lightning, and the evaporated water may destroy the blade from inside. In addition, in winter, the water inside the blade may be frozen and swollen to destroy the blade. To inspect the inside of the blade trailing edge, make a hole in the trailing edge using a 5 mm drill, observe and check the bonded part, and perform repair as necessary.

The inspector hanging on a rope inspects the trailing edge and the drainage hole.

Key Benefits with Olympus

Olympus’s industrial videoscopes used for blade inspection are available in various types responding to varied inspection applications, with diameters φ4.0 to 8.5 mm and lengths 2 to 30 m. Olympus’s industrial videoscopes are used in the field of inspection of wind power generating facilities around the world thanks to the following excellent functions.

• Battery-powered: the inspector can use it even in a narrow nacelle without worrying about power cable.
• Compact and lightweight design: with excellent mobility, it can be easily carried to a high place.
• Dust-proof and drip-proof performance: also supports an inspection environment in which the region to be inspected is deposited with dust, droplets, etc.
• Various optical adapters: various optical adapters can be selected according to the inspection application.
• The articulation that enables the user to efficiently observe the target region: the lens direction can be appropriately and quickly adjusted using the hand-operating section.
• A highly durable scope insertion part: With a tungsten outer layer the videoscope achieves high robustness to withstand frequent insertion for inspection.

InHelp, inspection-supporting software that ensures recording of inspection * other than IPLEX YS

When inspecting a blade using a videoscope, a large number of images are taken. Unless information on the inspection region is reliably recorded at the time of image recording, it will be impossible not only to complete an inspection record, but also to compare it with past inspection results. Our inspection-supporting software InHelp is useful in such circumstances. If an inspection is conducted using InHelp’s function, the inspection images will be classified and recorded in folders, and judgment information and a typical comment can be added to each inspection image. If a report is to be prepared after the inspection is completed, InHelp Viewer will help finish a report handling 50 or more images in short time.

Inspection equipment for other than visual inspection

In addition to industrial videoscopes, Olympus manufactures and sells ultrasonic flaw detectors and X-ray analyzers, which are used in large numbers for inspection of wind power generating facilities. Our ultrasonic flaw detectors visually achieve the inspection for internal breakage of the blade.
In addition, if our battery-powered compact X-ray analyzer (X5000) is used, the inspector can accurately assess the type, size and quantity of a metal contained in an obtained oil sample on site without sending the sample to the lab. Therefore, the soundness of the gear box can be diagnosed faster than before. For example, if an increase of a certain metal is observed with X5000, the inspector can promptly check the region where the metal is used with a videoscope and assess the condition in a timely manner.

Thus, Olympus’s industrial videoscopes and inspection equipment are adopted in the field of quality inspection of wind power generating facilities throughout the world. For details of the products, contact Olympus nearest to you.