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Wind energy Computerized Maintenance Management System (CMMS) : data collection recommendations for reliability analysis.

Description: This report addresses the general data requirements for reliability analysis of fielded wind turbines and other wind plant equipment. The report provides a list of the data needed to support reliability and availability analysis, and gives specific recommendations for a Computerized Maintenance Management System (CMMS) to support automated analysis. This data collection recommendations report was written by Sandia National Laboratories to address the general data requirements for reliability analysis of fielded wind turbines. This report is intended to help the reader develop a basic understanding of what data are needed from a Computerized Maintenance Management System (CMMS) and other data systems, for reliability analysis. The report provides: (1) a list of the data needed to support reliability and availability analysis; and (2) specific recommendations for a CMMS to support automated analysis. Though written for reliability analysis of wind turbines, much of the information is applicable to a wider variety of equipment and a wider variety of analysis and reporting needs.
Date: September 1, 2009
Creator: Peters, Valerie A.; Ogilvie, Alistair & Veers, Paul S.
Partner: UNT Libraries Government Documents Department

Field Verification Program for Small Wind Turbines, Quartelry Report: 2nd Quarter, Issue No.1, October 2000

Description: The Field Verification Program for Small Wind Turbines quarterly report provides industry members with a description of the program, its mission, and purpose. It also provides a vehicle for participants to report performance data, activities, and issues during quarterly test periods.
Date: November 2, 2000
Creator: Tu, P. & Forsyth, T.
Partner: UNT Libraries Government Documents Department

Wind Turbine Generator System Duration Test Report for the ARE 442 Wind Turbine

Description: This test is being conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, four turbines are being tested at the NWTC as a part of this project. Duration testing is one of up to 5 tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification. The test equipment includes a grid connected ARE 442 wind turbine mounted on a 30.5 meter (100 ft) lattice tower manufactured by Abundant Renewable Energy. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.
Date: May 1, 2010
Creator: van Dam, J.; Baker, D. & Jager, D.
Partner: UNT Libraries Government Documents Department

Wind turbine reliability : a database and analysis approach.

Description: The US wind Industry has experienced remarkable growth since the turn of the century. At the same time, the physical size and electrical generation capabilities of wind turbines has also experienced remarkable growth. As the market continues to expand, and as wind generation continues to gain a significant share of the generation portfolio, the reliability of wind turbine technology becomes increasingly important. This report addresses how operations and maintenance costs are related to unreliability - that is the failures experienced by systems and components. Reliability tools are demonstrated, data needed to understand and catalog failure events is described, and practical wind turbine reliability models are illustrated, including preliminary results. This report also presents a continuing process of how to proceed with controlling industry requirements, needs, and expectations related to Reliability, Availability, Maintainability, and Safety. A simply stated goal of this process is to better understand and to improve the operable reliability of wind turbine installations.
Date: February 1, 2008
Creator: Linsday, James; Briand, Daniel; Hill, Roger Ray; Stinebaugh, Jennifer A. & Benjamin, Allan S.
Partner: UNT Libraries Government Documents Department

Investigation of a FAST-OrcaFlex Coupling Module for Integrating Turbine and Mooring Dynamics of Offshore Floating Wind Turbines: Preprint

Description: To enable offshore floating wind turbine design, the following are required: accurate modeling of the wind turbine structural dynamics, aerodynamics, platform hydrodynamics, a mooring system, and control algorithms. Mooring and anchor design can appreciably affect the dynamic response of offshore wind platforms that are subject to environmental loads. From an engineering perspective, system behavior and line loads must be studied well to ensure the overall design is fit for the intended purpose. FAST (Fatigue, Aerodynamics, Structures and Turbulence) is a comprehensive simulation tool used for modeling land-based and offshore wind turbines. In the case of a floating turbine, continuous cable theory is used to emulate mooring line dynamics. Higher modeling fidelity can be gained through the use of finite element mooring theory. This can be achieved through the FASTlink coupling module, which couples FAST with OrcaFlex, a commercial simulation tool used for modeling mooring line dynamics. In this application, FAST is responsible for capturing the aerodynamic loads and flexure of the wind turbine and its tower, and OrcaFlex models the mooring line and hydrodynamic effects below the water surface. This paper investigates the accuracy and stability of the FAST/OrcaFlex coupling operation.
Date: October 1, 2011
Creator: Masciola, M.; Robertson, A.; Jonkman, J. & Driscoll, F.
Partner: UNT Libraries Government Documents Department

Estimation of fatigue and extreme load distributions from limited data with application to wind energy systems.

Description: An estimate of the distribution of fatigue ranges or extreme loads for wind turbines may be obtained by separating the problem into two uncoupled parts, (1) a turbine specific portion, independent of the site and (2) a site-specific description of environmental variables. We consider contextually appropriate probability models to describe the turbine specific response for extreme loads or fatigue. The site-specific portion is described by a joint probability distribution of a vector of environmental variables, which characterize the wind process at the hub-height of the wind turbine. Several approaches are considered for combining the two portions to obtain an estimate of the extreme load, e.g., 50-year loads or fatigue damage. We assess the efficacy of these models to obtain accurate estimates, including various levels of epistemic uncertainty, of the turbine response.
Date: January 1, 2004
Creator: Fitzwater, LeRoy M.
Partner: UNT Libraries Government Documents Department

CX-100 and TX-100 blade field tests.

Description: In support of the DOE Low Wind Speed Turbine (LWST) program two of the three Micon 65/13M wind turbines at the USDA Agricultural Research Service (ARS) center in Bushland, Texas will be used to test two sets of experimental blades, the CX-100 and TX-100. The blade aerodynamic and structural characterization, meteorological inflow and wind turbine structural response will be monitored with an array of 75 instruments: 33 to characterize the blades, 15 to characterize the inflow, and 27 to characterize the time-varying state of the turbine. For both tests, data will be sampled at a rate of 30 Hz using the ATLAS II (Accurate GPS Time-Linked Data Acquisition System) data acquisition system. The system features a time-synchronized continuous data stream and telemetered data from the turbine rotor. This paper documents the instruments and infrastructure that have been developed to monitor these blades, turbines and inflow.
Date: December 1, 2005
Creator: Holman, Adam (USDA-Agriculture Research Service, Bushland, TX); Jones, Perry L. & Zayas, Jose R.
Partner: UNT Libraries Government Documents Department

User's Guide to MBC3: Multi-Blade Coordinate Transformation Code for 3-Bladed Wind Turbine

Description: This guide explains how to use MBC3, a MATLAB-based script NREL developed to perform multi-blade coordinate transformation of system matrices for three-bladed wind turbines. In its current form, MBC3 can be applied to system matrices generated by FAST.2.
Date: September 1, 2010
Creator: Bir, G. S.
Partner: UNT Libraries Government Documents Department

Dynamic Characterization Testing of Wind Turbines

Description: The U.S. Department of Energy (DOE), in conjunction with the U.S. wind industry, is supporting the development and commercialization of utility-grade wind turbines. Under the Certification Program, the DOE, through the National Renewable Energy Laboratory (NREL) will assist the U.S. industry in obtaining American Association for Laboratory Accreditation (A2LA)-type certification for their class of wind turbine. As part of the Certification Program, NREL is conducting a suite of certification tests that are specified by the International Electro-technical Commission standards. One emerging certification requirement is to characterize the dynamic behavior of the wind turbine's operation. Therefore, the purpose of the dynamic characterization tests is to document the wind turbine's fundamental dynamic characteristics under critical operational modes and fault conditions in light of turbine design specifications. Some of the dynamic characteristics that we determine from testing include the conformation of fundamental structural vibration frequencies and the system's dynamic response to typical rated and extreme modes of operation. This paper discusses NREL's approach in designing and implementing a dynamic characterization test for commercial wind turbines. One important objective of the dynamic characterization test is to provide a Certification Agent with test data to show that the wind turbine's mechanical equipment is operating within design vibration limits. For NREL's industry participant, the test results are an indication of the wind system's overall quality of mechanical operation that can be used to compare with established industry standards for a wind system's response under typical and extreme operating conditions.
Date: May 31, 2001
Creator: Osgood, R.
Partner: UNT Libraries Government Documents Department

Identification of Wind Turbine Response to Turbulent Inflow Structures: Preprint

Description: The National Renewable Energy Laboratory conducted an experiment to obtain detailed wind measurements and corresponding wind turbine measurements in order to establish a causal relationship between coherent turbulent structures and wind turbine blade fatigue loads. Data were collected for one entire wind season from October 2000 to May 2001. During this period, the wind turbine operated under atmospheric conditions that support the formation of coherent turbulent structures 31% of the time. Using the equivalent fatigue load parameter as a measure of wind turbine blade fatigue and using statistical measures of the turbulent fluctuations of the wind, general correlation between the turbulence and the wind turbine response is shown. Direct correlation cannot be resolved with 10-minute statistics for several reasons. Multiple turbulent structures can exist within a 10-minute record, and the equivalent fatigue load parameter is essentially a 10-minute statistic that cannot estimate turbine response to individual turbulent structures. Large-magnitude turbulent fluctuations in the form of instantaneous Reynolds stresses do not necessarily correspond directly to large-magnitude blade root moment amplitudes. Thus, additional work must be done to quantify the negative turbine response and to correlate this response to turbulent inflow parameters over time scales less than 10 minutes.
Date: June 1, 2003
Creator: Hand, M. M.; Kelley, N. D. & Balas, M. J.
Partner: UNT Libraries Government Documents Department

Blade System Design Study. Part II, final project report (GEC).

Description: As part of the U.S. Department of Energy's Low Wind Speed Turbine program, Global Energy Concepts LLC (GEC)1 has studied alternative composite materials for wind turbine blades in the multi-megawatt size range. This work in one of the Blade System Design Studies (BSDS) funded through Sandia National Laboratories. The BSDS program was conducted in two phases. In the Part I BSDS, GEC assessed candidate innovations in composite materials, manufacturing processes, and structural configurations. GEC also made recommendations for testing composite coupons, details, assemblies, and blade substructures to be carried out in the Part II study (BSDS-II). The BSDS-II contract period began in May 2003, and testing was initiated in June 2004. The current report summarizes the results from the BSDS-II test program. Composite materials evaluated include carbon fiber in both pre-impregnated and vacuum-assisted resin transfer molding (VARTM) forms. Initial thin-coupon static testing included a wide range of parameters, including variation in manufacturer, fiber tow size, fabric architecture, and resin type. A smaller set of these materials and process types was also evaluated in thin-coupon fatigue testing, and in ply-drop and ply-transition panels. The majority of materials used epoxy resin, with vinyl ester (VE) resin also used for selected cases. Late in the project, testing of unidirectional fiberglass was added to provide an updated baseline against which to evaluate the carbon material performance. Numerous unidirectional carbon fabrics were considered for evaluation with VARTM infusion. All but one fabric style considered suffered either from poor infusibility or waviness of fibers combined with poor compaction. The exception was a triaxial carbon-fiberglass fabric produced by SAERTEX. This fabric became the primary choice for infused articles throughout the test program. The generally positive results obtained in this program for the SAERTEX material have led to its being used in innovative prototype blades of 9-m and ...
Date: May 1, 2009
Creator: Griffin, Dayton A. (DNV Global Energy Concepts Inc., Seattle, WA)
Partner: UNT Libraries Government Documents Department

Field Testing: Independent, Accredited Testing and Validation for the Wind Industry (Fact Sheet)

Description: This fact sheet describes the field testing capabilities at the National Wind Technology Center (NWTC). NREL's specialized facilities and personnel at the NWTC provide the U.S. wind industry with scientific and engineering support that has proven critical to the development of wind energy for U.S. energy needs. The NWTC's specialized field-testing capabilities have evolved over 30 years of continuous support by the U.S. Department of Energy Wind and Hydropower Technologies Program and long standing industry partnerships. The NWTC provides wind industry manufacturers, developers, and operators with turbine and component testing all in one convenient location. Although industry utilizes sophisticated modeling tools to design and optimize turbine configurations, there are always limitations in modeling capabilities, and testing is a necessity to ensure performance and reliability. Designs require validation and testing is the only way to determine if there are flaws. Prototype testing is especially important in capturing manufacturing flaws that might require fleet-wide retrofits. The NWTC works with its industry partners to verify the performance and reliability of wind turbines that range in size from 400 Watts to 3 megawatts. Engineers conduct tests on components and full-scale turbines in laboratory environments and in the field. Test data produced from these tests can be used to validate turbine design codes and simulations that further advance turbine designs.
Date: November 1, 2011
Partner: UNT Libraries Government Documents Department

Wind turbine reliability : understanding and minimizing wind turbine operation and maintenance costs.

Description: Wind turbine system reliability is a critical factor in the success of a wind energy project. Poor reliability directly affects both the project's revenue stream through increased operation and maintenance (O&M) costs and reduced availability to generate power due to turbine downtime. Indirectly, the acceptance of wind-generated power by the financial and developer communities as a viable enterprise is influenced by the risk associated with the capital equipment reliability; increased risk, or at least the perception of increased risk, is generally accompanied by increased financing fees or interest rates. Cost of energy (COE) is a key project evaluation metric, both in commercial applications and in the U.S. federal wind energy program. To reflect this commercial reality, the wind energy research community has adopted COE as a decision-making and technology evaluation metric. The COE metric accounts for the effects of reliability through levelized replacement cost and unscheduled maintenance cost parameters. However, unlike the other cost contributors, such as initial capital investment and scheduled maintenance and operating expenses, costs associated with component failures are necessarily speculative. They are based on assumptions about the reliability of components that in many cases have not been operated for a complete life cycle. Due to the logistical and practical difficulty of replacing major components in a wind turbine, unanticipated failures (especially serial failures) can have a large impact on the economics of a project. The uncertainty associated with long-term component reliability has direct bearing on the confidence level associated with COE projections. In addition, wind turbine technology is evolving. New materials and designs are being incorporated in contemporary wind turbines with the ultimate goal of reducing weight, controlling loads, and improving energy capture. While the goal of these innovations is reduction in the COE, there is a potential impact on reliability whenever new technologies are introduced. ...
Date: November 1, 2004
Partner: UNT Libraries Government Documents Department

Earthquake Response Modeling for a Parked and Operating Megawatt-Scale Wind Turbine

Description: Demand parameters for turbines, such as tower moment demand, are primarily driven by wind excitation and dynamics associated with operation. For that purpose, computational simulation platforms have been developed, such as FAST, maintained by the National Renewable Energy Laboratory (NREL). For seismically active regions, building codes also require the consideration of earthquake loading. Historically, it has been common to use simple building code approaches to estimate the structural demand from earthquake shaking, as an independent loading scenario. Currently, International Electrotechnical Commission (IEC) design requirements include the consideration of earthquake shaking while the turbine is operating. Numerical and analytical tools used to consider earthquake loads for buildings and other static civil structures are not well suited for modeling simultaneous wind and earthquake excitation in conjunction with operational dynamics. Through the addition of seismic loading capabilities to FAST, it is possible to simulate earthquake shaking in the time domain, which allows consideration of non-linear effects such as structural nonlinearities, aerodynamic hysteresis, control system influence, and transients. This paper presents a FAST model of a modern 900-kW wind turbine, which is calibrated based on field vibration measurements. With this calibrated model, both coupled and uncoupled simulations are conducted looking at the structural demand for the turbine tower. Response is compared under the conditions of normal operation and potential emergency shutdown due the earthquake induced vibrations. The results highlight the availability of a numerical tool for conducting such studies, and provide insights into the combined wind-earthquake loading mechanism.
Date: October 1, 2010
Creator: Prowell, I.; Elgamal, A.; Romanowitz, H.; Duggan, J. E. & Jonkman, J.
Partner: UNT Libraries Government Documents Department

Progress in Implementing and Testing State-Space Controls for the Controls Advanced Research Turbine: Preprint

Description: Designing wind turbines with maximum energy production and longevity for minimal cost is a major goal of the federal wind program and the wind industry. Control can improve the performance of wind turbines by enhancing energy capture and reducing dynamic loads. At the National Renewable Energy Laboratory (NREL) we are designing state-space control algorithms for turbine speed regulation and load reduction and testing them on the Controls Advanced Research Turbine (CART). The CART is a test-bed especially designed to test advanced control algorithms on a two-bladed teetering hub upwind turbine. In this paper we briefly describe the design of control systems to regulate turbine speed in region 3 for the CART. These controls use rotor collective pitch to regulate speed and also enhance damping in the 1st drive-train torsion, 1st rotor symmetric flap mode, and the 1st tower fore-aft mode. We designed these controls using linear optimal control techniques using state estimation based on limited turbine measurements such as generator speed and tower fore-aft bending moment. In this paper, we describe the issues and steps involved with implementing and testing these controls on the CART, and we show simulated tests to quantify controller performance. We then present preliminary results after implementing and testing these controls on the CART. We compare results from these controls to field test results from a baseline Proportional Integral control system. Finally we report conclusions to this work and outline future studies.
Date: December 1, 2004
Creator: Wright, A. D.; Fingersh, L. J. & Stol, K. A.
Partner: UNT Libraries Government Documents Department

Mechanical Design, Analysis, and Testing of a Two-Bladed Wind Turbine Hub

Description: Researchers at the National Wind Technology Center (NWTC) in Golden, Colorado, began performing the Unsteady Aerodynamics Experiment in 1993 to better understand the unsteady aerodynamics and structural responses of horizontal-axis wind turbines. The experiment consists of an extensively instrumented, downwind, three-bladed, 20-kilowatt wind turbine. In May 1995, I received a request from the NWTC to design a two-bladed hub for the experiment. For my thesis, I present the results of the mechanical design, analysis, and testing of the hub. The hub I designed is unique because it runs in rigid, teetering, or independent blade-flapping modes. In addition, the design is unusual because it uses two servomotors to pitch the blades independently. These features are used to investigate new load reduction, noise reduction, blade pitch optimization, and yaw control techniques for two-bladed turbines. I used a methodology by G. Phal and W. Bietz to design the hub. The hub meets all the performance specifications except that it achieves only 90% of the specified teeter range. In my thesis, I focus on the analysis and testing of the hub body. I performed solid-mechanics calculations, ran a finite-element analysis simulation, and experimentally investigated the structural integrity of the hub body.
Date: June 1, 2002
Creator: Cotrell, J.
Partner: UNT Libraries Government Documents Department