scholarly journals Probabilistic and Risk-Informed Life Extension Assessment of Wind Turbine Structural Components

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 821
Author(s):  
Jannie Sønderkær Nielsen ◽  
Lindsay Miller-Branovacki ◽  
Rupp Carriveau
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Wind Farm ◽  
Assessment Method ◽  
Economic Feasibility ◽  
Life Extension ◽  
Structural Components ◽  
Safety Factors ◽  
Original Design ◽  
Partial Safety Factors

Reassessment of the fatigue life for wind turbine structural components is typically performed using deterministic methods with the same partial safety factors as used for the original design. However, in relation to life extension, the conditions are generally different from the assumptions used for calibration of partial safety factors; and using a deterministic assessment method with these partial safety factors might not lead to optimal decisions. In this paper, the deterministic assessment method is compared to probabilistic and risk-based approaches, and the economic feasibility is assessed for a case wind farm. Using the models also used for calibration of partial safety factors in IEC61400-1 ed. 4, it is found that the probabilistic assessment generally leads to longer additional fatigue life than the deterministic assessment method. The longer duration of the extended life can make life extension feasible in more situations. The risk-based model is applied to include the risk of failure directly in the economic feasibility assessment and it is found that the reliability can be much lower than the target for new turbines, without compromising the economic feasibility.

Reliability Analysis and Risk-Based Methods for Planning of Operation and Maintenance of Offshore Wind Turbines

2017 ◽  
Author(s):  
John Dalsgaard Sørensen
Keyword(s):  
Wind Turbine ◽  
Reliability Analysis ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Offshore Wind ◽  
Special Focus ◽  
Life Cycle Approach ◽  
Structural Components ◽  
Safety Factors ◽  
Partial Safety Factors

Reliability analysis and probabilistic models for wind turbines are considered with special focus on structural components and application for reliability-based calibration of partial safety factors. The main design load cases to be considered in design of wind turbine components are presented including the effects of the control system and possible faults due to failure of electrical / mechanical components. Considerations are presented on the target reliability level for wind turbine structural components. Application is shown for reliability-based calibrations of partial safety factors for extreme and fatigue limit states are presented. Operation & Maintenance planning often follows corrective and preventive strategies based on information from condition monitoring and structural health monitoring systems. A reliability- and risk-based approach is presented where a life-cycle approach is used. An example with wind turbine blades is considered using the NORCOWE reference wind farm.

scholarly journals Three-Stage Wind Turbine Assessment Method: Condition Monitoring, Failure Prediction, And Health Assessment

2021 ◽  
Author(s):  
Yongsheng Qi ◽  
Tongmei Jing ◽  
Chao Ren ◽  
Xuejin Gao
Keyword(s):  
Wind Turbine ◽  
Condition Monitoring ◽  
Wind Farm ◽  
Health Management ◽  
Health Assessment ◽  
Failure Prediction ◽  
Fuzzy Comprehensive Evaluation ◽  
Assessment Method ◽  
Generalized Regression Neural Network ◽  
Monitoring Method

Abstract To improve the wind turbine shutdown early warning ability, we present a generalized model for wind turbine (WT) prognosis and health management (PHM) based on the data collected from the SCADA system. First, a new condition monitoring method based on kernel entropy component analysis (KECA) was developed for nonlinear data. Then, an aggregate statistic T was designed to express the state change of the monitoring parameters. As the features were submerged because of the diversity and nonlinearity of SCADA data, an enhanced generalized regression neural network (GRNN) method—KECA-GRNN—for failure prediction was developed by adding KECA for feature extraction to improve the predictive performance. Finally, the results of the KECA-GRNN model were visualized by a bubble chart, which made the health assessment results of the WT more intuitive. Similarly, the fusion residual was defined to analyze the health trend of the WT, and the health status of the WT was represented by two visualization methods—bubble chart and fuzzy comprehensive evaluation. Furthermore, they were evaluated using SCADA data that were collected from a wind farm. Observations from the results of the model indicated the ability of the approach to trend and assess turbine degradation before known downtime occurrences.

Fatigue Life Extension of Offshore Structures by Ultrasonic Peening

2011 ◽  
Author(s):  
Luis Lopez Martinez
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Fatigue Resistance ◽  
Structural Integrity ◽  
High Stress ◽  
Offshore Structures ◽  
Life Extension ◽  
Original Design ◽  
Ultrasonic Peening ◽  
Offshore Installations

The service life of offshore installations is limited by its structural integrity. Furthermore the structural integrity is mainly governed by the fatigue resistance of critical welded details. In a FPSO installation these details are among others pallet stools weld joints to deck structure and bulkheads/web frames weld connections to longitudinal in ballast tanks. ultrasonic peening can improve the fatigue resistance of welded joints. Fatigue test results shows an increase of four times for high stress ranges and up to ten times for high cycle fatigue. For specimens which have already consumed half of their fatigue life the treatment resets the clock to zero, as a minimum value. Consequently ultrasonic peening treatment was applied to several offshore installations on fatigue sensitive weld connections with the objective to extend the service life of the these. Finite Element Analysis carried out by classification societies for these offshore structures demonstrated critical fatigue lives for several weld connections. These weld connections were then treated by ultrasonic peening with the objective to extend their fatigue lives and by doing that reach the targeted service life for the installation. The successful application of the ultrasonic peening treatment was a pioneering work which involved several partners. A pilot project on a FPSO started in 2005 and the treated critical weld connections are still intact and show not sign of crack initiation despite the fact the calculations then showed shorter fatigue lives than the life span already consumed. As a result the same ultrasonic peening procedure has been proposed to be applied for other fatigue sensitive locations on the installation. Offshore installations around the world are reaching their original design life. Most of the operators chose to extend the service life of their assets rather than scrape them and build new. The reasons for that are: improved oil recovering techniques, time required to get a new build installation on site, environment concerns, wiser management of energy and resources among others. Therefore the Life Extension of Offshore Installations is a subject of current interest for the upstream industry.

scholarly journals Technical feasibility analysis and fluid dynamic simulation of a wind farm in the Northern region of Rio de Janeiro

2021 ◽  
Author(s):  
Osmarino Campelo Júnior ◽  
Silvio Eduardo Teixeira Pinto da Silva ◽  
André Machado Ribeiro de Souza
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Rio De Janeiro ◽  
Wind Farm ◽  
Northern Region ◽  
Economic Feasibility ◽  
Feasibility Analysis ◽  
Dynamics Simulation ◽  
Technical Feasibility ◽  
Wind Potential

The use of fossil fuels as an energy source is linked to a series of problems, ranging from the possibility of depletion of these resources to pollution and environmental damage caused by their extraction. In this context, wind energy emerges as a clean, renewable and viable option for electrical energy, which Brazil has a large amount of resources to be explored. In 2020, wind energy surpassed natural gas, becoming the second largest source of electricity in Brazil, previewing to reaching a share of 13.7% of total generation from new enterprises that will come into operation . With this, feasibility studies and computer simulation have become increasingly important to reduce costs associated with prospecting new sites with wind potential. The present work aims to elaborate a technical feasibility analysis and computational simulation of a wind farm in the northern region of Rio de Janeiro. Initially, prospective studies will be carried out to select a suitable location for a possible wind installation. Then, the potential of the chosen location will be evaluated, based on wind data available in the literature, so that the technical feasibility of wind generation can be analyzed. To perform the fluid dynamics simulation, the ANSYS Software will be used, where initially several geometric profiles of helix and helical turbines will be studied to then define the type of mesh that best discretizes the wind turbine. From this work, it is expected to find a location with good wind potential in the northern region of Rio de Janeiro, where there is technical and economic feasibility for the installation of a plant; and verify the behavior of the wind turbine and its arrangement at the selected location

A Comparison of Fracture Assessment Methods in Several Structural Integrity Assessment Procedures

2009 ◽  
Author(s):  
Tiecheng Yang ◽  
Xuedong Chen ◽  
Zhichao Fan
Keyword(s):  
Structural Integrity ◽  
Limit Load ◽  
Assessment Method ◽  
Assessment Methods ◽  
Safety Factors ◽  
Specific Calculation ◽  
Integrity Assessment ◽  
Fracture Assessment ◽  
Partial Safety Factors ◽  
Assessment Procedures

For the fracture assessment method internationally used in different structural integrity assessment procedures, such as R6, BS 7910, FITNET API 579 and GB/T 19624, this paper gives the results of analytical comparisons in combination with specific calculation examples by comparing different assessment options or levels, the partial safety factors (PSFs), limit load solutions, stress intensity factor solutions, residual stress distribution and treatment methods, secondary stresses and ρ factor solutions etc., which provide a basis for improvement of fracture assessment methods.

scholarly journals Wind Turbine Systematic Yaw Error: Operation Data Analysis Techniques for Detecting It and Assessing Its Performance Impact

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2351 ◽  
Author(s):  
Davide Astolfi ◽  
Francesco Castellani ◽  
Matteo Becchetti ◽  
Andrea Lombardi ◽  
Ludovico Terzi
Keyword(s):  
Data Analysis ◽  
Wind Turbine ◽  
Error Detection ◽  
Wind Farm ◽  
Assessment Method ◽  
Test Case ◽  
Performance Impact ◽  
Use Of Data ◽  
Yaw Angle ◽  
Multivariate Kernel Regression

The widespread availability of wind turbine operation data has considerably boosted the research and the applications for wind turbine monitoring. It is well established that a systematic misalignment of the wind turbine nacelle with respect to the wind direction has a remarkable impact in terms of down-performance, because the extracted power is in first approximation proportional to the cosine cube of the yaw angle. Nevertheless, due to the fact that in the wind farm practice the wind field facing the rotor is estimated through anemometers placed behind the rotor, it is challenging to robustly detect systematic yaw errors without the use of additional upwind sensory systems. Nevertheless, this objective is valuable because it involves the use of data that are available to wind farm practitioners at zero cost. On these grounds, the present work is a two-steps test case discussion. At first, a new method for systematic yaw error detection through operation data analysis is presented and is applied for individuating a misaligned multi-MW wind turbine. After the yaw error correction on the test case wind turbine, operation data of the whole wind farm are employed for an innovative assessment method of the performance improvement at the target wind turbine. The other wind turbines in the farm are employed as references and their operation data are used as input for a multivariate Kernel regression whose target is the power of the wind turbine of interest. Training the model with pre-correction data and validating on post-correction data, it is estimated that a systematic yaw error of 4 ∘ affects the performance up to the order of the 1.5% of the Annual Energy Production.

scholarly journals Site-specific assessment of wind turbine residual life and health status

2021 ◽  
Vol 261 ◽  
pp. 03057
Author(s):  
Ri Yang Guo ◽  
Wei Li ◽  
Hui Xia ◽  
Jiang Zhe Feng ◽  
Huai Hui Ren
Keyword(s):  
Health Status ◽  
Wind Turbine ◽  
Wind Farm ◽  
Residual Life ◽  
Load Condition ◽  
Economic Benefits ◽  
International Standards ◽  
Life Extension ◽  
Site Specific ◽  
Specific Assessment

At present, some 600kW and 750kW wind turbines put into operation earlier in China have exceeded their 20-year design life. For these turbines, the safety, reliability and economy of these turbines are usually evaluated in a reasonable way, so as to formulate life extension or decommissioning strategies to maximize economic benefits. Referring to the current international standards and guidelines, this paper takes a wind farm in South China as an example to evaluate the remaining life and state of the turbines. The external environment data of the met mast is extrapolated to the turbine site, and the load simulation is carried out based on the wind turbine model. The fatigue load set of the turbines under the design load condition and the site-specific load condition is obtained. The possible fatigue damage in the historical operation period is calculated. Combined with the linear damage accumulation theory of Miner, the fatigue of each turbine in the site is obtained by load analogy. The final P90 life is obtained by analyzing the uncertainty factors introduced in the assessment of residual life and health status.

Overview of Subsynchronous Oscillation in Grid-connected Wind Farm

2020 ◽  
Vol 13 (7) ◽  
pp. 969-979
Author(s):  
Xu Pei-Zhen ◽  
Lu Yong-Geng ◽  
Cao Xi-Min
Keyword(s):  
Power Systems ◽  
Wind Turbine ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Induction Generator ◽  
Future Research ◽  
Stable Operation ◽  
Subsynchronous Oscillation ◽  
Different Types

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.

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