Posters

Abstract

The site conditions assessment is a fundamental input of the Remaining Useful Lifetime (RUL) estimation. As meteorological masts data are not always available on aging wind farms, and new masts cannot always be installed, it is tempting to use other sources of data to perform a RUL estimation when considering a potential Lifetime Extension. For the purpose of this investigation, EDF R has analysed several sources: mast measurements, SCADA data, iSpin and virtual data. Yet, the reliability of those data, and its impact on load calculation, still has to be determined. The goal of this study is therefore to analyse how the quality of the sources available can affect the site conditions assessment and, consequently, the determination of the RUL of the turbines. EDF R has chosen as case study a wind farm of 8 wind turbines located in France, and characterized by a simple terrain without obstacles and an altitude between 130 m a.s.l. and 150 m a.s.l. A measurement campaign has been conducted in 2007 for the development of the wind farm and a supervision mast has been in place since its construction. In addition, the nacelle anemometer data are available, iSpin sensors have been installed for 3 years, and a virtual mast has been bought. All the data have been treated, analysed and used to define specific site conditions assessments. These analyses have been compared and used to perform RUL estimations on the wind turbines. In total 23 tests have been conducted, focusing on 3 specific wind turbines, each characterized by a different source of data or a different approach in the post-treatment. For example, a nacelle transfer function based on the supervision mast data has been applied for some tests. An additional shear sensitivity has been performed to better understand its impact on the RUL estimations obtained from iSpin and SCADA data. By performing a load assessment for each test, the estimated lifetime of the wind turbines has been compared with a designated base case. The discrepancies resulting from these comparisons enable the evaluation of the impact of these different sources of data and post-treating on the reliability of the RUL estimation. Overall, even when properly calibrated, iSpin device as well as SCADA data does not always give results in line with the standard approach based on mast data, even on a simple terrain. The shear and the turbulence intensity, having a relevant impact on the assessed lifetime of the turbines, cannot always be properly computed with these data. This effect might even be stronger on a more complex terrain. SCADA data can be used to provide indicative results that could help choosing whether to further investigate lifetime extension possibilities.