Advanced nacelle anemometry and SCADA-data, analysis techniques and limitations Frank Ormel Chief Specialist in Product Integration Vestas
Outline Introduction State of the art Advanced methods Nacelle Power Curve standard Conclusion Contributors: Irene Lauret Ducosson, Martin de Mare, Rolf Erik Keck, Carsten Krogh Nielsen 2
The purpose: performance monitoring and park optimisation 3
The problem: correlation to free stream wind 4
The problem: correlation to free stream wind 5
Apparent AEP & real AEP Original power curve The apparent effect of a nacelle anemometer measurement error The real effect of the same nacelle anemometer measurement error It seems like the power performance has ben reduced by 10% whereas in reality it has been reduced by 0.5% 6
The problem: seasonal variation 7
State of the art: detection of icing AvgPower AvgPower Scatterplot of AvgPower vs Wind speed (Normalized) 1800 1600 1400 Day 2010-12-24 2010-12-25 2010-12-26 2010-12-27 2010-12-28 1200 1000 800 600 400 200 0 2 4 6 8 10 Wind speed (Normalized) 12 14 16 Scatterplot of AvgPower vs Wind speed (Normalized) 1800 1600 1400 1200 1000 800 600 400 Day 2010-12-18 2010-12-19 2010-12-20 2010-12-21 2010-12-22 2010-12-23 2010-12-24 2010-12-25 2010-12-26 2010-12-27 2010-12-28 2010-12-29 2010-12-30 2010-12-31 200 0 8 2 4 6 8 10 Wind speed (Normalized) 12 14 16
State of the art: incorrect pitching 9
State of the art: overview In general, we can confidently detect the following field performance issues: Icing Yaw error Pitch problems De-rating problem Curtailment Incorrect control parameters influencing performance Incorrect nacelle transfer function Directional influence 10
Standardisation: IEC 61400-12-2 standard The project team has submitted the FDIS to the IEC June 2012. When approved by the national committees the standard can be expected around summer 2013 The standard is not easier than -12-1; a lot of focus has been put in to reduce variance. Still, total uncertainty of the test is higher than -12-1 standard (power curve test with met-mast) Useability will largely depend on OEMs to be compliant with this standard through their software in which case costs are significantly lower than for a -12-1 test Main challenge is to separate terrain influence on wind speed from rotor infuence 11
Advanced techniques: NTF calculated by CFD Anemometer Sensor WindSpeed (m/s) 18.00 16.00 14.00 12.00 10.00 8.00 6.00 4.00 2.00 WS Correlation graph of Free WS vs Anemometer Sensor WS (CFD & Field) Anemometer_Right-CFD Anemometer_Left-CFD Anemometer_Right-Field Anemometer_Left-Field 0.00 0 2 4 6 8 10 12 14 16 Freestream WindSpeed (m/s) Some encouraging results but high variability from site to site and operator to operator. Not ready for field testing or standardisation Wind speeds Actuator disc Actuator line Field data 4 0.998 0.982 1.010 6 1.024-1.105 8 1.018 1.025 1.036 10 1.021 1.037 1.025 12 12 1.024 1.032 1.052 14 1.015 - - 16 1.009 1.008 -
Advanced techniques: Spinner anemometry Site calibration done Turbine running with spinner anemometer for half a year Availability 51% (100% of the data) per 10-min data set, 97% available (99% of the data per 10-min data set) Correlation to free stream wind has R 2 of 0.89, which is less than standard anemometer (R 2 = 0.97) Correlation to free stream turbulence is equally bad between standard anemometer and spinner anemometer More data requirement for spinner anemometery to establish itself as a valuable option 13
Limitations and Conclusions In order to get value out of nacelle anemometry data we have to overcome these limitations: Data quality currently lowers the capability of the analysis we are looking with foggy glasses and results are not clear Main challenge of understanding the physics through the available data data must be used to verify hypotheses, not only to postulate problems Data must be used together with other sources (other turbines, met-masts, other signals, logbooks While addressing these challenges, we can identify and solve a number of problems with park operation and add value by optimising park performance 14
Thank you for your attention