Analysis of Wind Turbine Aging through Operation Curves

Abstract

The worsening with age of technical systems performance is a matter of fact which is particularly timely to analyze for horizontal-axis wind turbines because they constitute a mature technology. On these grounds, the present study deals with the assessment of wind turbine performance decline with age. The selected test case is a Vestas V52 wind turbine, installed in 2005 at the Dundalk Institute of Technology campus in Ireland. Operation data from 2008 to 2019 have been used for this study. The general idea is analyzing the appropriate operation curves for each working region of the wind turbine: in Region 2 (wind speed between 5 and 9 m/s), the generator speed–power curve is studied, because the wind turbine operates at fixed pitch. In Region 2 12bevelledtrue (wind speed between 9 and 13 m/s), the generator speed is rated and the pitch control is relevant: therefore, the pitch angle–power curve is analyzed. Using a support vector regression for the operation curves of interest, it is observed that in Region 2, a progressive degradation occurs as regards the power extracted for given generator speed, and after ten years (from 2008 to 2018), the average production has diminished of the order of 8%. In Region 2 12bevelledtrue, the performance decline with age is less regular and, after ten years of operation, the performance has diminished averagely of the 1.3%. The gearbox of the test case wind turbine was substituted with a brand new one at the end of 2018, and it results that the performance in Region 2 12bevelledtrue has considerably improved after the gearbox replacement (+3% in 2019 with respect to 2018, +1.7% with respect to 2008), while in Region 2, an improvement is observed (+1.9% in 2019 with respect to 2018) which does not compensate the ten-year period decline (−6.5% in 2019 with respect to 2008). Therefore, the lesson is that for the test case wind turbine, the generator aging impacts remarkably on the power production in Region 2, while in Region 2 12bevelledtrue, the impact of the gearbox aging dominates over the generator aging; for this reason, wind turbine refurbishment or component replacement should be carefully considered on the grounds of the wind intensity distribution onsite.

Estimation of the Performance Aging of the Vestas V52 Wind Turbine through Comparative Test Case Analysis

“…The critical points of the approaches based on cumulative data can be overcome through an in-depth analysis of wind turbines' operation data and operation curves [24,25], which allows disentangling the aging effects from reliability degradation or ambient effects. In a nutshell, aging can be distinguished with respect to reliability by considering the behavior of operation curves when the wind turbines are running.…”

“…In a nutshell, aging can be distinguished with respect to reliability by considering the behavior of operation curves when the wind turbines are running. Aging can be distinguished with respect to ambient effects by analyzing operation curves such as the generator speed-power, rotor speed-power, and blade pitch-power curves [25]. The drawback of this approach is that it is costly from the point of view of data analysis: for example, the studies in [24][25][26], which constitute the premise of this work, dealt with a unique wind turbine.…”

“…In particular, the results in [24,25] constitute the motivation of the present work: in those studies, a Vestas V52 wind turbine was studied, which is sited at the Dundalk Institute of Technology in Ireland. The wind turbine has been operating since 2005, and operation data from 2008 to 2019 were analyzed.…”

“…The earliest data set available was employed for training a support vector regression for the curves of interest, and the aging was quantified through the analysis of how the residuals between measurements and model estimates evolve as years pass by. The main result of [25] was that the performance decline with the age of the test case wind turbine can be ascribed mainly to the decline of generator performance: in Region 2, it is observed that progressively, the wind turbine extracts less power for a given generator rotational speed. Comparing the average performance after ten years of operation (2008 vs. 2018), a worsening in the order of 8% is observed.…”

Modeling of Ultra-Short Term Offshore Wind Power Prediction Based on Condition-Assessment of Wind Turbines

“…The declined health conditions of wind turbines will significantly reduce their capability of wind power generations [25]. R. Byrne et al and D. Astolfi et al assessed the wind turbine performance decline with age by analyzed the appropriate operation curves of wind turbine, the result shows that the efficiency reduced about 5% to 6.5% in the 10-year period decline [26,27]. In health condition assessment of wind turbines, several jobs have been done for evaluating the condition variations of the WTs.…”