Vestas

About: Vestas is a company organization based out in Aarhus, Denmark. It is known for research contribution in the topics: Turbine & Wind power. The organization has 1075 authors who have published 1519 publications receiving 23285 citations. The organization is also known as: Vestas Wind Systems & Vestas Wind Systems A/S.

What is Business Process Management?: A two stage literature review of an emerging field

Abstract: Business Process Management (BPM) is an emerging new field in business. However there is no academically agreed upon conceptual framework. The aim of this paper is to establish a conceptual framework grounded in the recent literature. The purpose of this work is to ensure a better foundation for future research and to discussion of the implications of BPM on Enterprise Information Systems (EIS). The starting point of this study is a focused literature review of the BPM concept. This literature review leads to the formulation of a conceptual framework for BPM which is evaluated using a quantitative lexical analysis of a broader literature sample. Finally the implication of the BPM on EIS is discussed and potential future research opportunities are outlined.

Method for manufacturing a blade spar for a wind turbine

Abstract: A method for manufacturing a blade spar for a wind turbine blade includes positioning a first spar segment having a first adhering portion; positioning a second spar segment having a second adhering portion at the first spar segment such that the first adhering portion and the second adhering portion are at least partially overlapping, wherein an adhesive is at least partially provided between the overlapping adhering portions; providing at least one fiber layer impregnated with an uncured resin on the outer surfaces of the first and second spar segments at least in the joint region of the first and second spar segments; and simultaneously curing the adhesive and the resin, thereby fixating the first and the second spar segments to each other

A multiprotocol wind turbine system and method

Abstract: The invention relates to a wind turbine, comprising at least two communication protocol handlers (PH), said protocol handlers (PH) comprising means for generating and interpreting SCADA related data (SCADA: Supervisory Control And Data Acquisition) according to an associated communication protocol and wherein said at least two protocol handlers (PH) being associated to different communication protocols.

A consistent turbulence formulation for the dynamic wake meandering model in the atmospheric boundary layer

Abstract: This thesis describes the further development and validation of the dynamic meandering wake model for simulating the flow field and power production of wind farms operating in the atmospheric boundary layer (ABL). The overall objective of the conducted research is to improve the modelling capability of the dynamics wake meandering model to a level where it is sufficiently mature to be applied in industrial applications and for an augmentation of the IEC-standard for wind turbine wake modelling. Based on a comparison of capabilities of the dynamic wake meandering model to the requirement of the wind industry, four areas were identified as high prioritizations for further research: 1. the turbulence distribution in a single wake 2. multiple wake deficits and build-up of turbulence over a row of turbines 3. the effect of the atmospheric boundary layer on wake turbulence and wake deficit evolution 4. atmospheric stability effects on wake deficit evolution and meandering The conducted research is to a large extent based on detailed wake investigations and reference data generated through computational fluid dynamics simulations, where the wind turbine rotor has been represented by an actuator line model. As a consequence, part of the research also targets the performance of the actuator line model when generating wind turbine wakes in the atmospheric boundary layer. Highlights of the conducted research: 1. A description is given for using the dynamic wake meandering model as a standalone flow-solver for the velocity and turbulence distribution, and power production in a wind farm. The performance of the standalone implementation is validated against field data, higher-order computational fluid dynamics models, as well as the most common engineering wake models in the wind industry. 2. The EllipSys3D actuator line model, including the synthetic methods used to model atmospheric boundary layer shear and turbulence, is verified for modelling the evolution of wind turbine wake turbulence by comparison to field data and wind tunnel experiments. 3. A two-dimensional eddy viscosity model is implemented to govern the distribution of turbulent stresses in the wake deficit. The modified eddy viscosity model improves the least-square fit of the velocity field in the wake by ~13% when compared to higher-order models. 4. A method is proposed to couple the increased turbulence level experienced by a turbine operating in waked conditions, to the downstream wake evolution of the wake-affected turbine. The intraturbine turbulence coupling improved the fit of the turbulence distribution by ~40% and the wind speed distribution by ~30% over a row of eight turbines. 5. The effect of the atmospheric shear on the turbulent stresses in the wake is captured by including a local strain-rate contribution for the ambient shear gradient. This results in more realistic turbulent stress levels in regions of small wake deficit gradients; this is particularly important in the far-wake region where atmospheric shear gradients are an important contribution to the local strain-rate. 6. A method to include the effect of atmospheric stability on the wake deficit evolution and wake meandering is described. Including the atmospheric stability effects improved the model prediction of the mean velocity field by ~19% and of turbulence distribution by ~28% in unstable atmospheric conditions compared to actuator line results. The power production by a row of wind turbines aligned with the wind direction is reduced by ~10% in very stable conditions compared to very unstable conditions at the same turbulence intensity. This power drop is comparable to measurements from the North Hoyle and OWEZ wind farms.

Active current control in wind power plants during grid faults

Abstract: Modern wind power plants are required and designed to ride through faults in electrical networks, subject to fault clearing. Wind turbine fault current contribution is required from most countries with a high amount of wind power penetration. In order to comply with such grid code requirements, wind turbines usually have solutions that enable the turbines to control the generation of reactive power during faults. This paper addresses the importance of using an optimal injection of active current during faults in order to fulfil these grid codes. This is of relevant importance for severe faults, causing low voltages at the point of common coupling. As a consequence, a new wind turbine current controller for operation during faults is proposed. It is shown that to achieve the maximum transfer of reactive current at the point of common coupling, a strategy for optimal setting of the active current is needed. Copyright © 2010 John Wiley & Sons, Ltd.