High-tech remedies

Camera-equipped drones provide high-end display photos. (Photo: Batcam)
Camera-equipped drones provide high-end display photos. (Photo: Batcam)

When it comes to operation and costs, however, more trust is put into ground-supported camera systems, which are less susceptible to wind and supply photos of an equally brilliant quality. GEV Wind ­Power of England and their technology partner Cornis SAS of France, for example, have begun selling the ­Panoblade Inspection System for camera-based rotor blade inspection. First, the system takes pictures of each section of the blades of a turbine that has been brought to a halt before using algorithms to stitch them together into a full blade. Next, experts examine the results and record their findings in a planning tool for actual maintenance tasks. “We recognised the cost-effective and simple advantages of utilising the remote blade inspection ­system. With only one operator required to inspect up to five onshore turbines per day or three offshore turbines, this system will offer exceptional savings in both time and money,” says Alastair Gadney, Projects ­Director at GEV.

Specialists are essential

Because visual checks of the blades are only one side of the coin, specialists must be called in to do the actual work. Only they can determine how much ­damage there really is and whether a crack sounds hollow or has already cut far into the blade – or if the mark on the photo was simply dirt. For these interventions, GEV feeds the visual results into an enterprise resource planning tool. Such software helps plan ­demand-based, transparent repair. “The fundamental advantage is that it provides near real-time ­reporting on each maintenance job, thereby boosting efficiency and minimising errors generated during the manual processing of reports and invoices,” ­Gadney explains. Similar systems are available from ­Braendler Engineering (Aether Blade Inspection ­Service) and ­AtSite of Denmark.

A number of other tools can also be useful for deter­mining the condition of a blade, including thermo­graphic systems or ultrasound devices for detecting problems such as poor lamination and inclusions. Force Technology of Denmark is a specialist in this ­area. “We sell our systems to manufacturers who use ultrasound to inspect blade quality during production,” says Jens Erik Olsen of Force.

Force Technology’s devices automatically move over the blades, making delamination and inclusions visible with ultrasound. Variants include handheld scanners that allow service technicians to, for ­example, recognize the depth of cracks directly on the blade. “The scanner probes down to a depth of about 60 to 70 millimetres to document the damage. We train specialist inspectors to use these devices,” says Olsen.

Erosion eats away at blades

A special focus of inspections is on blades’ leading and trailing edges and tips. It is well worth checking these spots because erosion from rain poses a real threat to blade and paint manufacturers. For now, blade coatings have a large share of polyurethane. Depending on the blend, such products can have properties ranging from hard to soft or very elastic. Due to their extreme weather resistance, these chemical blends are basically the only choice. The problem is that they do not last anywhere near 20 years. “Their service lives are far less than ten years. In fact, erosion protection that lasted for six or seven years at the blade tips would already be considered exceptional. There are systems onshore that work quite well but also suffer damage because their erosion protection wears off,” says Stefan Brassel, blade expert at Deutsche Windtechnik Rotor und Turm GmbH­.


Similar Entries

The global wind turbine rotor blade market is expected to surpass US$ 7 Bn in revenues by 2017-end. The market is anticipated to grow at a CAGR of 21.2% during the period 2017-2025 and reach nearly US$ 33 Bn in revenues. According to Persistence Market Research (PMR), global wind energy installations have increased from 282.2 GW in 2012 to 486.7 GW in 2016. This is positively impacting the growth of the global wind turbine rotor blade market.

Schaeffler now offers its FAG flanged rotor bearing as a matched system comprising a bearing unit, lubricant, and sensors (pict.: Schaeffler)

How can typical rolling bearing damage in wind turbines, particularly in their rotor bearing supports, be identified early and even prevented altogether? Schaeffler has a solution to this complex challenge: A combination of sensors that are capable of monitoring the critical influencing variables for these types of damage.

DNV GL published its fourth annual PV Module Reliability Scorecard report. This year’s report finds that the reliability and durability of modules submitted to DNV GL for testing for the 2018 PV Module Reliability Scorecard generally improved in several of the test categories. However, in one of the test categories, damp heat, performance decreased. With 22% of manufacturers experiencing at least one failure in overall testing, buyers being conscious of the specific Bill of Materials (BOM) that identify specific models as Top Performers is crucial.

Schaeffler and ZF use jointly developed expert models to analyze and predict the condition of wind turbine gearboxes based on the actual loads that occur during operation

ZF Friedrichshafen and Schaeffler are collaborating to develop new solutions for predicting the operating life of wind turbine gearbox components based on the actual loads that occur during operation. Since September, the first wind turbine gearboxes equipped with sensors and condition monitoring systems have been supplying operating data to a cloud-to-cloud solution to enable this to happen.