News Article | November 19, 2015
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Foreman R.J.,Karlsruhe Institute of Technology |
Emeis S.,Karlsruhe Institute of Technology |
Canadillas B.,DEWI GmbH
Boundary-Layer Meteorology | Year: 2014
A turbulence parametrization for wind speed in the stable boundary layer consisting of a single empirical parameter is proposed without the use of the eddy viscosity concept or turbulent kinetic energy equation. Instead, a drag-coefficient-type formulation as a function of the bulk Richardson number has been found to be able to reproduce observed stable boundary-layer wind speeds as effectively as a model based on the eddy viscosity approach. The advantage of this simpler approach is that the model can, in theory, be modified more easily for certain applications, such as the effects of large-scale wind parks on mesoscale meteorology. © 2014, Springer Science+Business Media Dordrecht.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: ENERGY-2007-2.3-03 | Award Amount: 2.68M | Year: 2008
One of the major causes of failures of mechanical systems (e.g. drive trains, pitch systems, and yaw systems) in wind turbines is insufficient knowledge of the loads acting on these components. The objective of this pre-normative project is to set up a methodology that enables better specification of design loads for the mechanical components. The design loads will be specified at the interconnection points where the component can be isolated from the entire wind turbine structure (for gearboxes for instance the interconnection points are the shafts and the attachments to the nacelle frame). The focus will be on developing guidelines for measuring load spectra at the interconnection points during prototype measurements and to compare them with the initial design loads. Ultimately, the new procedures for the mechanical components will be brought at the same high level as the state-of-the-art procedures for designing and testing rotor blades and towers which are critical to safety. A well balanced consortium, consisting of a turbine manufacturer, component manufacturer, certification institute, and R&D institutes will describe the current practice for designing and developing mechanical components. Based on this starting point, the project team will draft improved procedures for determining loads at the interconnection points. The draft procedures will be applied to three case studies with each a different focus, viz. determining loads at the drive train, pitch system, and yaw system; the latter one taking into account complex terrain. The procedures will be assessed by the project team and depending on the outcome the procedures will be updated accordingly and disseminated. All partners will incorporate the new procedures in their daily practices for designing turbines and components, certifying them, and carrying out prototype measurements. Project results will be submitted to relevant standardisation committees.
Munoz-Esparza D.,Von Karman Institute for Fluid Dynamics |
Canadillas B.,DEWI GmbH |
Neumann T.,DEWI GmbH |
Van Beeck J.,Von Karman Institute for Fluid Dynamics
Journal of Renewable and Sustainable Energy | Year: 2012
This paper is focused on the evaluation of five planetary boundary layer (PBL) schemes in the Weather Research and Forecasting model for offshore wind energy purposes. One first order scheme: Yonsey University and four one-and-a-half order schemes: Mellor-Yamada-Janić, Quasi-Normal Scale Elimination, Mellor-Yamada-Nakanishi-Niino, and Bougeault-Lacarrère, are considered. Turbulent flux measurements from the FINO1 platform in the North Sea are used to estimate the Obukhov length, allowing the sorting of the data into different stability classes. In addition, wind LiDAR measurements are used to analyze wind profiles up to 251.5m, encompassing the heights where today's wind turbines operate. The ability of the different PBL schemes to forecast turbulent fluxes of heat and momentum and surface stability is evaluated. Obukhov length results show that in general, PBL schemes forecast more moderated stable stratifications and a reinforcement of the instability for neutral and convective conditions, compared to FINO1 observations. The vertical structure of the wind speed profile is thoroughly analyzed for stable, near-neutral, unstable, and very unstable conditions by using total shear stresses, eddy diffusivities, and wind speed shears. The Mellor-Yamada-Nakanishi-Niino scheme presents the best agreement with measurements considering the different atmospheric stabilities analyzed. Stable conditions are the most complicated scenario for the PBL schemes to reproduce due to their overdiffusive formulations, which effect is to lower the vertical wind shear. Under such conditions, Quasi-Normal Scale Elimination and Yonsey University outperform the rest of the PBL schemes, the latest using a revised diffusion formulation. © 2012 American Institute of Physics.
Klosse R.,DEWI GmbH
European Wind Energy Conference and Exhibition 2010, EWEC 2010 | Year: 2010
The main changing's in the technical guideline TR3, which are resulting out of the German renewable energy feed in law extension (SDLWindV), are measurements of the reactive power capability, the ramp rate limitation after grid false and the set point control for active and reactive power in accuracy and reconnection time. The most complex and costly part is the documentation about the behavior during grid false. It is not only required to ride through a voltage dip (LVRT) also the turbine has to deliver a high value of reactive power immediately after the voltage is dropped down. In the new German feed in law for renewables from 2009 the system stability is considered substantial. The main focus is that especially the wind turbine generators are work more and more like big power station. The requirements of the German Transmission Code from 2007 for high volt connections and for the medium voltage connection (BDEW Richtlinie) from 2008 are legitimate by the law and are precised in some topics by in the extension of the EEG the SDLWindV form summer 2009. For that wind turbine how fulfill all requirements the fee will increase. Turbines connected after June of 2010 have to fulfill everything anyway. But how to ensure the availability of the new requirements? For that the handling of power quality measurement has change. The technical guideline TR3 of the power quality measurement of the Fordergesellschaft Windenergie (FGW, fund association wind energy) gets the now the new 20th revision. This TR3 is related mainly to the IEC 61400-21 ed. 2 but has some significant extensions. Additional two new technical guidelines the TR4 for modeling and the TR8 for certification are introduced and are now in the revision 4 and revision 1. Out of the fact that this guidelines still under development new changing's are expected up to the end of 2009 or at the beginning of 2010. Out of the changing's of the IEC 61400-21 from edition 1 to edition 2 the MEASNET procedure was adduced as well. MEASNET is a cluster of international measurement institutions in Europe and USA for to harmonizes measurements procedures. DEWI will presents the most important changing's of these guidelines in the actual version at time of presenting. As well this presentation will gives an overview about there experience to perform such measurement. The main changing's in the technical guideline TR3, which are resulting out of the German renewable energy feed in law extension (SDLWindV), are measurements of the reactive power capability, the ramp rate limitation after grid false and the set point control for active and reactive power in accuracy and reconnection time. The most complex and costly part is the documentation about the behavior during grid false. It is not only required to ride through a voltage dip (LVRT) also the turbine has to deliver a high value of reactive power immediately after the voltage is dropped down.
DEWI GmbH | Date: 2013-01-28
Central processing units; Communications controllers; Communications processing computer software; Computer apparatus; Computer controllers; Computer firmware; Computer operating programs; Computer operating programs, recorded; Computer operating system software; Computer operating systems; Computer programmes; Computer software for use in computer access control; Computer software for use in remote meter monitoring; Computer software for use in remote meter reading; Computers for managing control devices for wind power installations; Electric power controllers; Electrical controllers; Electronic controllers; Ethernet controllers; Factory automation software; Industrial process control software; Invertor controllers; Operating software; Operating system programs; Operating systems; Power controllers; Process computers; Process control apparatus; Process control apparatus; Process control configuration; Process control digital controllers; Process control instruments; Process control instruments; Process control units; Process control units; Process controllers; Process controllers; Process controlling software; Process indicators; Process monitors; Programmable control apparatus; Programmable controllers; Programmable controls; Programmable digital read-out units; Programmable electronic apparatus; Programs (Computer operating -) recorded; Remote controllers; Terminal controllers; VPN operating software.
DEWI GmbH | Date: 2013-01-28
Towers (metal structures), namely towers and masts of metal for wind energy installations; Nacelles for wind energy installations. Alternators; Anti-vibration mountings for machines; Axles for machines; Blade holders (parts of machines); Blades (machine parts); Blades for wind energy installations; Rotors; Brakes for industrial machines; Brakes for machines; Brushes being parts of generators; Brushes being parts of motors, generators and dynamos; Casing rings (parts of machines); Casings for industrial machines; Controls (Hydraulic -) for machines, motors and engines; Crankcases for machines, motors and engines; Drive units, other than for land vehicles; Drives for machines; Electric drives for motors (other than for land vehicles); Electric generator power sets; Electric generators; Electrical drives for machines; Engine speed governors; Gear assemblies, other than for land vehicles; Gear boxes for hydraulic transmissions (other than for land vehicles); Gear boxes other than for land vehicles; Gear cases, other than for land vehicles; Gear motors other than for land vehicles; Gear units for machines; Gear units for power transmissions, other than for land vehicles; Geared electric motors, other than for land vehicles; Gearing for machines; Generators; Generators for wind turbines; Housings (parts of machines); Housings for machines; Hydrostatic drives; Machine holders being stands (being adapted for the machine); Nacelles; Planetary gear transmissions, other than for land vehicles; Power installations (generators); Power shift transmissions (other than for land vehicles); Power supply apparatus (generators); Power supply devices (generators); Power transmissions and gearing for machines (not for land vehicles); Radiators (cooling) for motors and engines; Regulators (parts of machines); Regulators being machine parts; Regulators for machines; Regulators for motors; Shaft mounted gear units (other than for land vehicles); Shafts for machines; Speed governers (mechanical) for machines, engines and motors; Speed governors for machines, engines and motors; Stands for machines; Transmission control mechanisms; Transmission members, other than for land vehicles; Variable speed drives for machines; Variable speed transmissions (other than for land vehicles); Wind-powered electricity generators; all the aforesaid goods for wind energy installations. Electrical controllers; Electrical power control apparatus; Electronic regulators; Electronic transformers; Power analyzers; Power capacitors; Power conditioners; Power controlling apparatus(electric); Power dividers (electric); Power meters; Power packs (transformers); Power switches; Revolution counters; Speed reducers (electrical); Speed reducers (electronic); Speed regulators (electrical); Speed regulators (electronic); Step-up transformers; Tap changers for electric transformers; Transformers; Transformers (electricity).
DEWI GmbH | Date: 2013-10-08
DEWI GmbH | Date: 2014-03-27
Watches, watch cases, buckles and clasps for watch straps, movements for timepieces, watch straps, watch dials, winding rings, alarm clocks, clocks,wall clocks, watch boxes, pocket watches; jewelry, namely bracelets, rings, necklaces, earrings, pendants, brooches, cufflinks; all the aforesaid goods with the exception of a so-called napolon coin or an imitation thereof.
DEWI GmbH | Date: 2010-07-01
Baseball caps and hats; Jackets; T-shirts. Providing a website featuring technology that enables users to upload and share videos, upload and share photos and images, search jobs within the arts and entertainment fields, search for talent and future employees in the arts and entertainment fields, online chat with other website users, create a personal profile page, vote and rate videos and musical bands, post blogs and resumes, upload and share music tracks and songs, send messages to other users and members of the site.