Wind Turbine performance improvement and life extension, current limitations and solutions

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Since the onset of the Wind Energy industry, Wind Turbine (WT) performance has been managed in contractual terms. Fixed and subsidized energy prices induced a contractual approach, where measuring and controlling Original Equipment Manufacturer (OEM) commitments remained at the heart of the productive activity. The pillars of this system were built on Supervisory Control and Data Acquisition (SCADA) and long-distance wind measurement, with expensive equipment such as measurement masts, also called met masts.

With subsidies decreasing, attention is now shifting to increasing the performance of the Wind turbine, rather than simply attaining contractual performance. This implies a strong change in mindset as well as new tools and approaches. Instead of managing according to artificial values, Wind turbine owners and operators now need to understand real environmental values such as wind speed and direction, turbulence, and aerodynamic imbalance. 

Technology dedicated to contractual performance carried inherent limitations. Met masts placed 400m away from a turbine could not measure accurately either wind speed nor wind direction, especially in complex terrain. The same went with nacelle-based anemometers which could not possibly give an accurate wind direction due to the turbulence caused by the wind turbine blades. These margins of error were buffeted into the contractual commitments. 

Now, with energy prices falling, it is necessary to identify this potential margin of optimization. The key to this undertaking is understanding the individual wind turbine characteristics which drive the wind blades, in effect, the wind directly in front of the blades. Only with measurements directly in front can the fundamental characteristics driving performance be identified. Precise wind direction and its angle with the nacelle direction (YAW), Turbulence Intensity (TI), and Wind Speed are all necessary to understand how well an owner is doing with respect to absolute potential. 

 

H2 The most effective solution of wind turbines diagnosis and monitoring: the WindEagle

This is where the most advanced and cost-effective technology comes into play, notably with Epsiline’s WindEagle system. This combination of advanced sensors and algorithms provides accurate (error < 0,5°) information for advanced monitoring, diagnostics and improvement.

At the core of the WindEagle lies a patented LiDAR technology which measures wind characteristics 10m in front of the device, in other words, directly in front of the blades. Beyond its high wind measurement accuracy, Epsiline’s LiDAR brings this advanced technology to all by reducing cost by an order of magnitude. Where traditional LiDAR cost in the vicinity of 100 000€, Epsiline’s approach makes it affordable to all by reducing the cost by 10 for wind farms. 

Epsiline’s LiDAR technology forms the cornerstone of an advanced yet easily useable solution. Accurate measurements of wind speeds, turbulence intensity and direction are completed by further sensors including Pressure, Temperature & Humidity (PTU), vibration and GPS. All these sensors are contained in the compact WindEagle which is installed in less than 2 hours on top of the nacelle. Data is transmitted via the cellular networks directly to Epsiline’s secure servers where the information can then be processed either through Epsiline’s advanced algorithms or through an API key for more customized analysis. Algorithm results and parameters are then accessed through Epsiline’s Webportal, giving full diagnostics to understand, monitor and improve performance.

With accurate and reliable information now readily available, fundamental performance traits are automatically be analyzed, starting with Yaw, TI and Aerodynamic Imbalance.

H2 8° of Static Yaw error can have a 3% impact on productivity loss

With 60% of wind turbines presenting relevant Static Yaw and 30% marked Static Yaw, this is the first parameter requiring attention, as an 8° Static Yaw can represent a 3% productivity loss

Correcting the static yaw also contributes to the reduction of excessive stress loads that leads to longer asset life and reduction in major component replacements.

Measurement campaigns can be carried out relatively quickly with relevant information available within 10 days. Once correction is made by realigning the wind turbine, then verification can be made that productivity has increased.

In addition to Static Yaw, Epsiline’s WindEagle can contribute to reducing dynamic Yaw as demonstrated on a Siemens Gamesa WT.

Turbulence intensity is the next parameter to be addressed as considerable productivity loss can be caused by excessive or improper curtailment strategies. TI is caused not only by terrain, but also by neighbouring WT which create a Wake Effect. Epsiline’s WindEagle will provide clear and precise directional information on TI, allowing to understand accurately the impact of the other turbines, and eventually implementing a Wake Steering strategy.

Aerodynamic Imbalance due to either weight or blade angle also leads to losses in productivity. Once an Aerodynamic Imbalance is detected and corrected, true performance improvement is measured by combining the vibration with the WindEagle’s wind data. 

Beyond analysis and productivity improvement, when the WindEagle is left permanently on the nacelle, automatic monitoring can be implemented to improve maintenance and ensure optimal productivity. Alerts are programmed to have email notifications sent whenever preset or customised thresholds have been crossed. 

Epsiline’s WindEagle is positioned to support the Wind Industry in its transformation, by focusing on optimal performance through state-of-the-art sensors allowing for real-time and real-life data transmission, analysis and improvement.

To learn more click here.

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