You can’t manage what you don’t measure.
This is an old management phrase that is still accurate today. Unless you measure something, you don't know if it is getting better or worse. You can't manage for improvement if you don't measure to see what is getting better and what isn’t.
On a day and age, where economic benefits are a primary concern to all decision makers, sane engineering processes must rely of consistent, accurate and repeatable data.
The most used method to date to access and evaluate the condition of wind turbine blades is either by rope inspection or ground based photographic snapshots. These methods are best used to detect and/or correct existing damages, and on the rope access there are human safety considerations to take into account.
Surveys performed by drones brought the promise of better images but fell short of their promise. The common methods, where manually operating a drone at close vicinity of a wind turbine, require, not only a very experienced human pilot, but are far of being safe, consistent and repeatable, and end up providing a collection of snapshots that hardly reflect what O&M managers need to see, and often, are just “another” collection of snapshots.
The promise of having not just a lot of images, but real actionable engineering data was still a promise, when Pro-Drone began the work of transforming the survey of wind turbine blades from a curiosity, to a real engineering tool.
After two years developing a drone based solution, the Pro-Drone system is a reality today, with proven track record of surveying hundreds of wind turbine blades per month, per team, and delivering not only complete blade imagery, with resolutions better than 0,4mm per pixel, but also detailed automated reports. This gives the stakeholders, O&M personnel, manufacturers, insurance companies, repair teams, etc, a detailed condition report of each and every turbine blade on their portfolio and enables the monitoring of the lifetime of the blades.
First, Pro-Drone consulted with some of the largest wind turbine owners in the world and what they expect to see from a visual inspection, and what would be actionable data.
Pro-Drone tackled the problem as an engineering challenge and divided it in several steps.
The client would have to be able to:
• order a survey of any of his assets in a easy way;
• order and compare reports by one or more blade experts;
• evaluate the results quickly and easily;
• annotate any location of the blade with accurate precision;
• keep an historical track record of blade condition;
• integrate with existing maintenance systems.
The operations would have to be:
• Surveys should be carried within a short time frame and minimize the down time of the WTG;
• Human intervention on the drone should be kept to the minimum legally allowed;
• The system should be able to adapt itself to any shape and size of blade, without human intervention;
• Total blade area coverage;
• The survey results would have to be automatically uploaded and processed;
• The resolution of the images must enable detection of micro cracks.
The target was set to see the damages below 1 mm/pixel, on the entire surface of the wind turbine blade.
And from this objective, a solution was developed that would be able to survey an entire blade in a consistent repeatable way and maintaining the optical resolution below that target.
The obvious choice to interact with the users/clients was to choose a web-based platform, that enabled a easy, versatile way to deal with the retried data.
Although the amount of data was very large, Pro-Drone managed to implement a process that could process a large amount of data - one blade side could have more than 100 high resolution images.
The way that a drone would perform the survey was developed to be a robotic system that adapts itself to any shape, size, model of wind turbine blade, and release the humans of such a hard task. Extensive tests were performed to fine tune the system, and the current solution performs the required tasks according to the requirements.
Although the easy solution would be to “throw money” at the problems and either build from scratch or use custom, expensive solutions, Pro-Drone chose to go with readily available off-the shelf components and integrate them with a smart solution.
What this allows, is to release the robotic part of the system, from the drone, and that any appropriate commercial drone can be used to operate.
An added benefit of this approach is to allow existing drone operators to use the Pro-Drone system like any regular add-on gimbal to collect the data.
Soon after starting a discrete commercial approach, it was obvious that the solution was a clear differentiator factor from any other existing similar solutions.
With average resolutions of 0,4mm/pixel (clearly much better than the initial goal), full blade coverage, defect accurate location and sizing, easy and familiar interface, the customers could easily order detailed inspection reports of the condition of their wind turbine blades from reputable and existing inspectors.
The current solution allows the use of any kind of classification matrix of defects and recommendations, thus enabling customers to maintain their existing “defects” book, or even to compare reports from different inspectors or companies, and in the end export the results on common formats, or even integrate with existing maintenance management systems.
Also, the turnaround time, between ordering a survey and the availability of the results was well within the scope, and it is possible to have written reports in less than 24 hours after the survey, thus enabling timely decisions by the responsible persons.
The experience of the Pro-Drone system by its first customers is very positive, and prove that the system works reliably, and already has a track record of more than 1600 wind turbine blades inspected in a little more than 3 months.
The Pro-Drone system is also very affordable to purchase and operate even by smaller companies because of the choice that was done to use readily available components to build the system.
At this moment, the customer base of the system is very varied and either wind turbine blades manufacturers, park owners, park operators and traditional inspection companies are using the system on daily base to perform detailed analysis.
As an added benefit of the solution, it can be used to gather aggregate data from several wind turbine blades, and easily identify not only the regular defects, but also statistical data on entire groups of blades.
Pro-Drone, hasn’t stopped the development and is already studying and developing the next steps to further automate and develop the survey of wind turbine blades…but our initial goal to enable management of assets by measuring them has been achieved.
The sky is not the limit, it’s our office.