Statistical Analysis of Component Failures: A 16 Year Survey on More Than 550 Wind Turbines

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Lorenzo Ferrari ◽  
Guido Soldi ◽  
Alessandro Bianchini ◽  
Enzo Dalpane
Keyword(s):  
Statistical Analysis ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Good Prediction ◽  
Component Failure ◽  
Machine Age ◽  
Detailed Survey ◽  
Maintenance Program ◽  
Component Failures

A good prediction of the failure ratio of wind turbine (WT) components is pivotal to define a correct maintenance program and reduce the downtime periods. Even a small failure can lead to long downtime periods and high repairing costs. The installation sites, which generally have limited accessibility, and the necessity of special facilities to reach the components inside the nacelle, also play a key role in the correct management of WTs. In this study, a detailed survey on the failures occurred to the WTs managed by the Italian operator “e2i energie speciali” (more than 550 machines) over 16 years was performed and the results were analyzed in detail. Each failure was classified by considering the damaged component and the related downtime period. The analysis allowed the determination of several useful results such as the trend of failure occurrence with machine age and the identification of components and macrocomponents which are more critical in terms of both number of occurrences and downtime periods. The combination of component failure occurrences and related downtime periods was also computed to estimate which component is most critical for WT operation.

Statistical Analysis of Component Failures: A 16-Year Survey on More Than 550 Wind Turbines

2018 ◽  
Author(s):  
Lorenzo Ferrari ◽  
Guido Soldi ◽  
Alessandro Bianchini ◽  
Enzo Dalpane
Keyword(s):  
Statistical Analysis ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Good Prediction ◽  
Component Failure ◽  
Machine Age ◽  
Detailed Survey ◽  
Maintenance Program ◽  
Component Failures

A good prediction of the failure ratio of wind turbine components is pivotal in order to define a correct maintenance program and reduce the downtime periods. Even a small failure can lead to long downtime periods and high repairing costs. The installation sites, which generally have limited accessibility, and the necessity of special facilities to reach the components inside the nacelle, also play a major role in the correct management of wind turbines. In this study, a detailed survey on the failures occurred to the wind turbines managed by the Italian operator “e2i energie speciali” (more than 550 machines) over 16 years was performed and the results were analyzed in detail. Each failure was classified by considering the damaged component and the related downtime period. The analysis allowed the determination of several useful results such as the trend of failure occurrence with machine age and the identification of components and macro-components which are more critical in terms of both number of occurrences and downtime periods. The combination of component failure occurrences and related downtime periods was also computed to estimate which component is most critical for wind turbine operation.

Overview of Wind Turbine Field Failure Databases: A Discussion of the Requirements for an Analysis

2018 ◽  
Author(s):  
Roozbeh Bakhshi ◽  
Peter Sandborn
Keyword(s):  
Statistical Analysis ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farms ◽  
Onshore Wind ◽  
Failure Times ◽  
Reliability Parameters ◽  
Failure Data ◽  
Offshore Installations ◽  
Field Failure

With renewable energy and wind energy in particular becoming mainstream means of energy production, the reliability aspect of wind turbines and their sub-assemblies has become a topic of interest for owners and manufacturers of wind turbines. Operation and Maintenance (O&M) costs account for more than 25% of total costs of onshore wind projects and these costs are even higher for offshore installations. Effective management of O&M costs depends on accurate failure prediction for turbine sub-assemblies. There are numerous models that predict failure times and O&M costs of wind farms. All these models have inputs in the form of reliability parameters. These parameters are usually generated by researchers using field failure data. There are several databases that report the failure data of operating wind turbines and researches use these failure data to generate the reliability parameters through various methods of statistical analysis. However, in order to perform the statistical analysis or use the results of the analysis, one must understand the underlying assumptions of the database along with information about the wind turbine population in the database such as their power rating, age, etc. In this work, we analyze the relevant assumptions and discuss what information is required from a database in order to improve the statistical analysis on wind turbines’ failure data.

How to Improve the Reliability of Wind Turbines

2011 ◽  
Vol 58-60 ◽  
pp. 771-775
Author(s):  
Hai Bo Zhang ◽  
Liang Liu
Keyword(s):  
Wind Turbine ◽  
Monitoring System ◽  
Condition Monitoring ◽  
Wind Turbines ◽  
Lubrication System ◽  
Component Failure ◽  
Time Condition ◽  
Automatic Lubrication ◽  
Potential Component ◽  
Condition Monitoring System

According to the failure of wind turbines in operation, the failure cause and phenomenon of wind turbines is analyzed, combined with the reliability of wind turbine subsystems, measures aiming at cooperation parts and purchased parts are proposed, the reliability of the whole wind turbines is improved in a certain extent. At the same time, condition monitoring system can carry through the early detecting and diagnosing to potential component failure maintain. Besides, automatic lubrication system can realize accurate and timeliness lubrication, also can reduce maintenance workload, preserve correct lubrication and smooth running of all parts.

Evaluation Criteria and Estimate of Output From a Small-Scale Wind Turbine

2011 ◽  
Author(s):  
Dorothy S. Small
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Profile ◽  
Historical Data ◽  
Three Dimensional ◽  
Evaluation Criteria ◽  
Specific Site ◽  
Small Scale ◽  
Site Conditions

This paper will evaluate a specific site located in southwestern Virginia, providing design criteria that are important considerations at this site. The evaluation will predict the output from a 6 blade HAWT model at the height and location of the site. As a small scale wind turbine, the process of determination of relevant considerations to establish the turbine selection and output are weighted to establish the evaluation criteria. A review of the specific site conditions are presented in detail. This information includes: three-dimensional topographic review, wind and weather profile of the site and surrounding environmental conditions of the site. With this information the decision path for the specific siting is discussed. Characteristics of the site that will be considered to calculate output are: historical data of wind profile of the region, height of tower, affect of other objects and affect of wind turbulence. A discussion of current modeling options will be compared. The design and components of the small scale wind turbine chosen for this application will be compared to other wind turbines of similar size and cost. Considerations of the turbine that are considered are: size of wind turbine, cost of wind turbine, predictable output of the wind turbine based on design of the various wind turbines, requirements for the tower for each turbine and predicted maintenance for each turbine. Initial performance of the selected turbine will be available by presentation of information.

Increasing the regulating ability of lift force in the power-limited mode of wind turbines based on plasma technology

2016 ◽  
Vol 41 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Sergey N Udalov ◽  
Andrey A Achitaev ◽  
Richard D Tarbill
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Lift Force ◽  
Theoretical Calculations ◽  
Dielectric Strength ◽  
Plasma Actuator ◽  
National Renewable Energy Laboratory ◽  
Plasma Technology ◽  
Elastic Deformations

This article presents theoretical calculations of using a plasma actuator in a wind turbine for increasing its regulating ability. Calculations were done taking into account the pressure difference caused by an ozone layer. A series of calculations were carried out based on the QuickField software with the use of calculations of elastic deformations for determination of the influence on the resultant lift force. Distribution of the dielectric strength was calculated that is required for estimation of the ionization area. Vector diagrams were presented which show the influence of the plasma actuator at different sides of a wind turbine blade on the resultant lift force. The equation describing the influence of the plasma actuator was derived. Investigations carried out in this article have shown that the maximum regulating effect is about 25%. It should be noted that the position of the plasma actuator on the blade also influences the value of the lift force. Therefore, regulating properties of wind turbines are improved. Theoretical calculations were validated experimentally at the National Renewable Energy Laboratory in Denver. Note that the main advantages of the plasma actuator as the part of a wind turbine are simplicity and the possibility of increasing regulating properties of a wind turbine.

Determination of Wake Propagation Downstream of the Wind Turbine Using Computational Fluid Dynamics

2012 ◽  
Author(s):  
Abolfazl Pourrajabian ◽  
Reza Ebrahimi ◽  
Masoud Mirzaei
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Turbulence Modeling ◽  
Governing Equations ◽  
Horizontal Axis Wind Turbine ◽  
Velocity Magnitude

A numerical scheme for determination of wake propagation in downstream of a wind turbine was developed by Computational Fluid Dynamics (CFD) and analytical correlation. A 3bladed horizontal axis wind turbine was selected and airflow around the wind turbine was analyzed. The flow was assumed steady state and a pressure based approach was adopted to solve the governing equations in an unstructured grid distribution using parallel processing. In conjunction with governing equations, the kω – SST model was used for turbulence modeling. The formation of the wake behind the wind turbine was estimated and an appropriate equation was derived for velocity magnitude at the downstream of the wind turbine. Moreover, the suitable distances between wind turbines in wind and crosswind directions were estimated. Results show a good agreement between the previous researches and the comparison indicates that the CFD could be considered as a proper tool for determination of wake properties, windward and crosswind distance between wind turbines in a wind farm.

scholarly journals On the Determination of the Aerodynamic Damping of Wind Turbines Using the Forced Oscillations Method in Wind Tunnel Experiments

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2452 ◽  
Author(s):  
Robert Fontecha ◽  
Frank Kemper ◽  
Markus Feldmann
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Forced Oscillations ◽  
Scale Model ◽  
Wind Tunnel Experiments ◽  
Aerodynamic Damping ◽  
Safe Side ◽  
Reynolds Number Effects

The development of wind turbine technology has led to higher and larger wind turbines with a higher sensitivity to dynamic effects. One of these effects is the aerodynamic damping, which introduces favorable damping forces in oscillating wind turbines. These forces play an important role in the turbine lifetime, but have not yet been studied systematically in detail. Consequently, this paper studies the plausibility of determining the aerodynamic damping of wind turbines systematically through wind tunnel experiments using the forced oscillation method. To this end, a 1:150 scale model of a prototype wind turbine has been fabricated considering Reynolds number effects on the blades through XFOIL calculations and wind tunnel measurements of airfoil 2D-section models. The resulting tower and wind turbine models have been tested for different operation states. The tower results are approximate and show low aerodynamic damping forces that can be neglected on the safe side. The measured aerodynamic damping forces of the operating turbine are compared to existing analytic approaches and to OpenFAST simulations. The measured values, although generally larger, show good agreement with the calculated ones. It is concluded that wind tunnel forced oscillations experiments could lead to a better characterization of the aerodynamic damping of wind turbines.

EXPERIMENTAL AND ANALYTICAL STUDIES OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 51-58
Author(s):  
B. P. Khozyainov
Keyword(s):  
Wind Turbine ◽  
Flow Velocity ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Air Flow ◽  
Geometrical Parameters ◽  
Wind Speeds ◽  
Analytical Studies ◽  
Air Flow Velocity

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

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.

Calculating the aerodynamics of vertical axis wind turbines

2012 ◽  
Vol 34 (3) ◽  
pp. 169-184 ◽  
Author(s):  
Hoang Thi Bich Ngoc
Keyword(s):  
Wind Turbine ◽  
Incidence Angle ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Velocity Triangle ◽  
Relationship Of ◽  
The Relationship

Vertical axis wind turbine technology has been applied last years, very long after horizontal axis wind turbine technology. Aerodynamic problems of vertical axis wind machines are discussible. An important problem is the determination of the incidence law in the interaction between wind and rotor blades. The focus of the work is to establish equations of the incidence depending on the blade azimuth, and to solve them. From these results, aerodynamic torques and power can be calculated. The incidence angle is a parameter of velocity triangle, and both the factors depend not only on the blade azimuth but also on the ratio of rotational speed and horizontal speed. The built computational program allows theoretically selecting the relationship of geometric parameters of wind turbine in accordance with requirements on power, wind speed and installation conditions.

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