Analysis and Observations of Wind Turbine Yaw Dynamics

1989 ◽  
Vol 111 (4) ◽  
pp. 367-371 ◽  
Author(s):  
A. C. Hansen ◽  
X. Cui

Two models of the yaw behavior of horizontal axis wind turbines are presented and discussed. Emphasis in this paper is on the description of the models and underlying assumptions with details of the equations and solution methods referenced in technical reports. The more complex model (YawDyn) considers the coupling of blade flap motions and yaw motions which result from temporal and spatial variations in the approaching wind speed. The new methods are unique in that they simultaneously model the effects of skewed wake aerodynamics and blade stall. Both of these effects must be considered if yaw behavior is to be adequately understood. The models are validated by comparison with other prediction techniques, wind tunnel tests and full-scale atmospheric tests. In all cases the models are shown to give excellent qualitative agreement and reasonable quantitative agreement. It is concluded that the new models represent a significant improvement in the methods available to the wind turbine designer for understanding yaw loads and motions.

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5623
Author(s):  
Davide Astolfi ◽  
Raymond Byrne ◽  
Francesco Castellani

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 12 (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 12, 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 12 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 12, 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.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4503
Author(s):  
Arash E. Samani ◽  
Jeroen D. M. De Kooning ◽  
Nezmin Kayedpour ◽  
Narender Singh ◽  
Lieven Vandevelde

This article investigates the impact of the pitch-to-stall and pitch-to-feather control concepts on horizontal axis wind turbines (HAWTs) with different blade designs. Pitch-to-feather control is widely used to limit the power output of wind turbines in high wind speed conditions. However, stall control has not been taken forward in the industry because of the low predictability of stalled rotor aerodynamics. Despite this drawback, this article investigates the possible advantages of this control concept when compared to pitch-to-feather control with an emphasis on the control performance and its impact on the pitch mechanism and structural loads. In this study, three HAWTs with different blade designs, i.e., untwisted, stall-regulated, and pitch-regulated blades, are investigated. The control system is validated in both uniform and turbulent wind speed. The results show that pitch-to-stall control enhances the constant power control for wind turbines with untwisted and stall-regulated blade designs. Stall control alleviates the fore-aft tower loading and the blades flapwise moment of the wind turbine with stall-regulated blades in uniform winds. However, in turbulent winds, the flapwise moment increases to a certain extent as compared to pitch-to-feather control. Moreover, pitch-to-stall control considerably reduces the summed blade pitch movement, despite that it increases the risk of surface damage in the rolling bearings due to oscillating movements with a small amplitude.


2014 ◽  
Vol 695 ◽  
pp. 801-805 ◽  
Author(s):  
Azizul Mohamad ◽  
Nasrul Amri Mohd Amin ◽  
Hong Tee Toh ◽  
Mohd Shukry Abdul Majid ◽  
Ruslizam Daud

Wind turbine is a device used to convert kinetic energy into electrical energy. Generally, wind turbine could be classified as horizontal axis and vertical axis wind turbine, depending on its axis of rotation. Two major factors affecting wind turbine performance are wind speed and aerodynamic design. While wind speed is depending on the location and weather, aerodynamic design of the wind turbine could be improved and optimized to enhance the wind turbine efficiency. This paper summarized few such design with particular attention on output power analysis as well as analysis tools development, for both type of wind turbine.


Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.


Author(s):  
Salete Alves ◽  
Luiz Guilherme Vieira Meira de Souza ◽  
Edália Azevedo de Faria ◽  
Maria Thereza dos Santos Silva ◽  
Ranaildo Silva

Proceedings ◽  
2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Youssra El Qasemy ◽  
Abdelfatah Achahbar ◽  
Abdellatif Khamlichi

The stochastic behavior of wind speed is a particular characteristic of wind energy production, which affects the degradation mechanism of the turbine, resulting in stochastic charging on the wind turbine. A model stochastic is used in this study to evaluate the efficiency of wind turbine power of whatever degree given fluctuating wind turbulence data. This model is based on the Langevin equations, which characterize, by two coefficients, drift and diffusion functions. These coefficients describe the behavior of the transformation process from the input wind speed to the output data that need to be determined. For this present work, the computation of drift and diffusion functions has been carried out by using the stochastic model to assess the output variables in terms of the torque and power curves as a function of time, and it is compared by the classical method. The results show that the model stochastic can define the efficiency of wind turbine generation more precisely.


Author(s):  
Sadek Ameziane ◽  
Abdesselem Chikhi ◽  
Mohammed Salah Aggouner

Background: The presented article is a contribution to the realization of a wind emulator based on a continuous-current machine. The development of this topic focuses on the modeling of a vertical axis wind turbine, a DC motor with independent excitation and its control via a chopper. Methods: To carry out this work, we have studied and designed the electronic and mechanical sensors as well as a command implemented on the dSPACE DS1103 system. Results: The main purpose of this work is related, on one hand, to the control of the motor turbine by imposing the wind profile and on the other hand generate the command of the implanted MPPT. The experimental results obtained showed the great performances which characterize this improved wind energy system. Conclusion: Finally, a wind turbine with variable speed is a system having a complex model; however, a detailed model of the interaction between the wind and the aero-turbine is useful to understand certain phenomena such as rotational sampling or the spatial filter.


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