WorldWideScience

Sample records for large wind farms

  1. Research on large-scale wind farm modeling

    Science.gov (United States)

    Ma, Longfei; Zhang, Baoqun; Gong, Cheng; Jiao, Ran; Shi, Rui; Chi, Zhongjun; Ding, Yifeng

    2017-01-01

    Due to intermittent and adulatory properties of wind energy, when large-scale wind farm connected to the grid, it will have much impact on the power system, which is different from traditional power plants. Therefore it is necessary to establish an effective wind farm model to simulate and analyze the influence wind farms have on the grid as well as the transient characteristics of the wind turbines when the grid is at fault. However we must first establish an effective WTGs model. As the doubly-fed VSCF wind turbine has become the mainstream wind turbine model currently, this article first investigates the research progress of doubly-fed VSCF wind turbine, and then describes the detailed building process of the model. After that investigating the common wind farm modeling methods and pointing out the problems encountered. As WAMS is widely used in the power system, which makes online parameter identification of the wind farm model based on off-output characteristics of wind farm be possible, with a focus on interpretation of the new idea of identification-based modeling of large wind farms, which can be realized by two concrete methods.

  2. Power fluctuations from large wind farms - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Pinson, P.; Cutululis, N.A.; Madsen, Henrik; Jensen, Leo Enrico; Hjerrild, J.; Heyman Donovan, M.; Vigueras-ROdriguez, A.

    2009-08-15

    Experience from power system operation with the first large offshore wind farm in Denmark: Horns Rev shows that the power from the wind farm is fluctuating significantly at certain times, and that this fluctuation is seen directly on the power exchange between Denmark and Germany. This report describes different models for simulation and prediction of wind power fluctuations from large wind farms, and data acquired at the two large offshore wind farms in Denmark are applied to validate the models. Finally, the simulation model is further developed to enable simulations of power fluctuations from several wind farms simultaneously in a larger geographical area, corresponding to a power system control area. (au)

  3. Prospects for generating electricity by large onshore and offshore wind farms

    Science.gov (United States)

    Volker, Patrick J. H.; Hahmann, Andrea N.; Badger, Jake; Jørgensen, Hans E.

    2017-03-01

    The decarbonisation of energy sources requires additional investments in renewable technologies, including the installation of onshore and offshore wind farms. For wind energy to remain competitive, wind farms must continue to provide low-cost power even when covering larger areas. Inside very large wind farms, winds can decrease considerably from their free-stream values to a point where an equilibrium wind speed is reached. The magnitude of this equilibrium wind speed is primarily dependent on the balance between turbine drag force and the downward momentum influx from above the wind farm. We have simulated for neutral atmospheric conditions, the wind speed field inside different wind farms that range from small (25 km2) to very large (105 km2) in three regions with distinct wind speed and roughness conditions. Our results show that the power density of very large wind farms depends on the local free-stream wind speed, the surface characteristics, and the turbine density. In onshore regions with moderate winds the power density of very large wind farms reaches 1 W m-2, whereas in offshore regions with very strong winds it exceeds 3 W m-2. Despite a relatively low power density, onshore regions with moderate winds offer potential locations for very large wind farms. In offshore regions, clusters of smaller wind farms are generally preferable; under very strong winds also very large offshore wind farms become efficient.

  4. Siemens Wind Power 3.6 MW wind turbines for large offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Akhmatov, Vladislav; Nygaard Nielsen, Joergen; Thisted, Jan; Groendahl, Erik; Egedal, Per; Noertoft Frydensbjerg, Michael; Jensen, Kim Hoej [Siemens Wind Power A/S, Brande (Denmark)

    2008-07-01

    Siemens Wind power A/S is the key player on the offshore wind power market. The Siemens Wind Power 3.6 MW variable-speed wind turbine is among the word's largest, most advanced and competitive wind turbines with a solid portfolio of large offshore wind farms. Transmission system operators and developers require dynamic wind turbine models for evaluation of fault-ride-through capability and investigations of power system stability. The even larger size of the on- and offshore wind farms has entailed that the grid impact of the voltage and frequency control capability of the wind farm can be appropriated modelled and evaluated. Siemens Wind Power has developed a dynamic model of the 3.6 MW variable-speed wind turbine with the fault-ride-through sequences and models of the voltage and frequency controllers to be applied for large offshore wind farms. The dynamic models have been implemented in the commercially available simulation tools such as DIgSILENT PowerFactory and Siemens PTI PSS/E and successfully validated from measurements. (orig.)

  5. Operation and control of large wind turbines and wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Thomsen, Kenneth (and others)

    2005-09-01

    This report is the final report of a Danish research project 'Operation and control of large wind turbines and wind farms'. The objective of the project has been to analyse and assess operational strategies and possibilities for control of different types of wind turbines and different wind farm concepts. The potentials of optimising the lifetime/energy production ratio by means of using revised operational strategies for the individual wind turbines are investigated. Different strategies have been simulated, where the power production is decreased to an optimum when taking loads and actual price of produced electricity into account. Dynamic models and control strategies for the wind farms have also been developed, with the aim to optimise the operation of the wind farms considering participation in power system control of power (frequency) and reactive power (voltage), maximise power production, keep good power quality and limit mechanical loads and life time consumption. The project developed models for 3 different concepts for wind farms. Two of the concepts use active stall controlled wind turbines, one with AC connection and one with modern HVDC/VSC connection of the wind farm. The third concept is based on pitch controlled wind turbines using doubly fed induction generators. The models were applied to simulate the behaviour of the wind farm control when they were connected to a strong grid, and some initial simulations were performed to study the behaviour of the wind farms when it was isolated from the main grid on a local grid. Also the possibility to use the available information from the wind turbine controllers to predict the wind speed has been investigated. The main idea has been to predict the wind speed at a wind turbine using up-wind measurements of the wind speed in another wind turbine. (au)

  6. Effects of Turbine Spacings in Very Large Wind Farms

    DEFF Research Database (Denmark)

    farm. LES simulations of large wind farms are performed with full aero-elastic Actuator Lines. The simulations investigate the inherent dynamics inside wind farms in the absence of atmospheric turbulence compared to cases with atmospheric turbulence. Resulting low frequency structures are inherent...... in wind farms for certain turbine spacings and affect both power production and loads...

  7. Operation and Equivalent Loads of Wind Turbines in Large Wind Farms

    Science.gov (United States)

    Andersen, Soren Juhl; Sorensen, Jens Norkaer; Mikkelsen, Robert Flemming

    2017-11-01

    Wind farms continue to grow in size and as the technology matures, the design of wind farms move towards including dynamic effects besides merely annual power production estimates. The unsteady operation of wind turbines in large wind farms has been modelled with EllipSys3D(Michelsen, 1992, and Sørensen, 1995) for a number of different scenarios using a fully coupled large eddy simulations(LES) and aero-elastic framework. The turbines are represented in the flow fields using the actuator line method(Sørensen and Shen, 2002), where the aerodynamic forces and deflections are derived from an aero-elastic code, Flex5(Øye, 1996). The simulations constitute a database of full turbine operation in terms of both production and loads for various wind speeds, turbulence intensities, and turbine spacings. The operating conditions are examined in terms of averaged power production and thrust force, as well as 10min equivalent flapwise bending, yaw, and tilt moment loads. The analyses focus on how the performance and loads change throughout a given farm as well as comparing how various input parameters affect the operation and loads of the wind turbines during different scenarios. COMWIND(Grant 2104-09- 067216/DSF), Nordic Consortium on Optimization and Control of Wind Farms, Eurotech Greentech Wind project, Winds2Loads, and CCA LES. Ressources Granted on SNIC and JESS. The Vestas NM80 turbine has been used.

  8. Wind farm density and harvested power in very large wind farms: A low-order model

    Science.gov (United States)

    Cortina, G.; Sharma, V.; Calaf, M.

    2017-07-01

    In this work we create new understanding of wind turbine wakes recovery process as a function of wind farm density using large-eddy simulations of an atmospheric boundary layer diurnal cycle. Simulations are forced with a constant geostrophic wind and a time varying surface temperature extracted from a selected period of the Cooperative Atmospheric Surface Exchange Study field experiment. Wind turbines are represented using the actuator disk model with rotation and yaw alignment. A control volume analysis around each turbine has been used to evaluate wind turbine wake recovery and corresponding harvested power. Results confirm the existence of two dominant recovery mechanisms, advection and flux of mean kinetic energy, which are modulated by the background thermal stratification. For the low-density arrangements advection dominates, while for the highly loaded wind farms the mean kinetic energy recovers through fluxes of mean kinetic energy. For those cases in between, a smooth balance of both mechanisms exists. From the results, a low-order model for the wind farms' harvested power as a function of thermal stratification and wind farm density has been developed, which has the potential to be used as an order-of-magnitude assessment tool.

  9. Prospects for generating electricity by large onshore and offshore wind farms

    DEFF Research Database (Denmark)

    Volker, Patrick; Hahmann, Andrea N.; Badger, Jake

    2017-01-01

    large wind farms, winds can decrease considerably from their free-stream values to a point where an equilibrium wind speed is reached. The magnitude of this equilibrium wind speed is primarily dependent on the balance between turbine drag force and the downward momentum influx from above the wind farm......The decarbonisation of energy sources requires additional investments in renewable technologies, including the installation of onshore and offshore wind farms. For wind energy to remain competitive, wind farms must continue to provide low-cost power even when covering larger areas. Inside very...... on the local free-stream wind speed, the surface characteristics, and the turbine density. In onshore regions with moderate winds the power density of very large wind farms reaches 1 W m−2, whereas in offshore regions with very strong winds it exceeds 3 W m−2. Despite a relatively low power density, onshore...

  10. Harmonic Instability Source Identification in Large Wind Farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2017-01-01

    A large-scale power electronics based power system like a wind farm introduces the passive and active impedances. The interactions between the active and passive impedances can lead to harmonic-frequency oscillations above the fundamental frequency, which can be called harmonic instability....... This paper presents an approach to identify which wind turbine and which bus has more contribution to the harmonic instability problems. In the approach, a wind farm is modeled as a Multi-Input Multi-Output (MIMO) dynamic system. The poles of the MIMO transfer matrix are used to predict the system...... instability and the eigenvalues sensitivity analysis in respect to the elements of the MIMO matrix locates the most influencing buses of the wind farm. Time-domain simulations in PSCAD software environment for a 400-MW wind farm validate that the presented approach is an effective tool to determine the main...

  11. Investigation on the integral output power model of a large-scale wind farm

    Institute of Scientific and Technical Information of China (English)

    BAO Nengsheng; MA Xiuqian; NI Weidou

    2007-01-01

    The integral output power model of a large-scale wind farm is needed when estimating the wind farm's output over a period of time in the future.The actual wind speed power model and calculation method of a wind farm made up of many wind turbine units are discussed.After analyzing the incoming wind flow characteristics and their energy distributions,and after considering the multi-effects among the wind turbine units and certain assumptions,the incoming wind flow model of multi-units is built.The calculation algorithms and steps of the integral output power model of a large-scale wind farm are provided.Finally,an actual power output of the wind farm is calculated and analyzed by using the practical measurement wind speed data.The characteristics of a large-scale wind farm are also discussed.

  12. Cost optimization of wind turbines for large-scale offshore wind farms

    International Nuclear Information System (INIS)

    Fuglsang, P.; Thomsen, K.

    1998-02-01

    This report contains a preliminary investigation of site specific design of off-shore wind turbines for a large off-shore wind farm project at Roedsand that is currently being proposed by ELKRAFT/SEAS. The results were found using a design tool for wind turbines that involve numerical optimization and aeroelastic calculations of response. The wind climate was modeled in detail and a cost function was used to estimate costs from manufacture and installation. Cost of energy is higher for off-shore installations. A comparison of an off-shore wind farm site with a typical stand alone on-shore site showed an increase of the annual production of 28% due to the difference in wind climate. Extreme loads and blade fatigue loads were nearly identical, however,fatigue loads on other main components increased significantly. Optimizations were carried out to find the optimum overall off-shore wind turbine design. A wind turbine for the off-shore wind farm should be different compared with a stand-alone on-shore wind turbine. The overall design changed were increased swept area and rated power combined with reduced rotor speed and tower height. Cost was reduced by 12% for the final 5D/14D off-shore wind turbine from 0.306 DKr/kWh to 0.270 DKr/kWh. These figures include capital costs from manufacture and installation but not on-going costs from maintenance. These results make off-shore wind farms more competitive and comparable to the reference on-shore stand-alone wind turbine. A corresponding reduction of cost of energy could not be found for the stand alone on-shore wind turbine. Furthermore the fatigue loads on wind turbines in on-shore wind farms will increase and cost of energy will increase in favor of off-shore wind farms. (au) EFP-95; EU-JOULE-3; 21 tabs., 7 ills., 8 refs

  13. Energy Dynamics of an Infinitely Large Offshore Wind Farm

    DEFF Research Database (Denmark)

    Frandsen, Sten Tronæs; Barthelmie, R.J.; Pryor, S.C.

    , particularly in the near-term, can be expected in the higher resource, moderate water depths of the North Sea rather than the Mediterranean. There should therefore be significant interest in understanding the energy dynamics of the infinitely large wind farm – how wakes behave and whether the extraction...... of energy by wind turbines over a large area has a significant and lasting impact on the atmospheric boundary layer. Here we focus on developing understanding of the infinite wind farm through a combination of theoretical considerations, data analysis and modeling. Initial evaluation of power losses due...... is of about the same magnitude as for the infinitely large wind farm. We will examine whether this can be proved theoretically or is indicated by data currently available. We will also evaluate whether energy extraction at the likely scale of development in European Seas can be expected to modulate...

  14. Statistics of LES simulations of large wind farms

    DEFF Research Database (Denmark)

    Andersen, Søren Juhl; Sørensen, Jens Nørkær; Mikkelsen, Robert Flemming

    2016-01-01

    . The statistical moments appear to collapse and hence the turbulence inside large wind farms can potentially be scaled accordingly. The thrust coefficient is estimated by two different reference velocities and the generic CT expression by Frandsen. A reference velocity derived from the power production is shown...... to give very good agreement and furthermore enables the very good estimation of the thrust force using only the steady CT-curve, even for very short time samples. Finally, the effective turbulence inside large wind farms and the equivalent loads are examined....

  15. Flow and wakes in large wind farms. Final report for UpWind WP8

    Energy Technology Data Exchange (ETDEWEB)

    Barthelmie, R.J.; Frandsen, S.T.; Rathmann, O. (Risoe DTU (Denmark)); Hansen, K. (Technical Univ. of Denmark (DTU), Kgs. Lyngby (Denmark)); Politis, E.; Prospathopoulos, J. (CRES (Greece)); Schepers, J.G. (ECN, Petten (Netherlands)); Rados, K. (NTUA, Athens (Greece)); Cabezon, D. (CENER, Sarriguren (Spain)); Schlez, W.; Neubert, A.; Heath, M. (Garrad Hassan and Partners (Germany) (United Kingdom))

    2011-02-15

    This report summarises the research undertaken through the European Commission funded project UpWind Wp8:Flow. The objective of the work was to develop understanding of flow in large wind farms and to evaluate models of power losses due to wind turbine wakes focusing on complex terrain and offshore. A crosscutting activity was to improve and compare the performance of computational fluid dynamics models with wind farm models. The report contains 6 deliverable reports and guideline to wind farm wake analysis as appendices. (Author)

  16. Optimal control of energy extraction in LES of large wind farms

    Science.gov (United States)

    Meyers, Johan; Goit, Jay; Munters, Wim

    2014-11-01

    We investigate the use of optimal control combined with Large-Eddy Simulations (LES) of wind-farm boundary layer interaction for the increase of total energy extraction in very large ``infinite'' wind farms and in finite farms. We consider the individual wind turbines as flow actuators, whose energy extraction can be dynamically regulated in time so as to optimally influence the turbulent flow field, maximizing the wind farm power. For the simulation of wind-farm boundary layers we use large-eddy simulations in combination with an actuator-disk representation of wind turbines. Simulations are performed in our in-house pseudo-spectral code SP-Wind. For the optimal control study, we consider the dynamic control of turbine-thrust coefficients in the actuator-disk model. They represent the effect of turbine blades that can actively pitch in time, changing the lift- and drag coefficients of the turbine blades. In a first infinite wind-farm case, we find that farm power is increases by approximately 16% over one hour of operation. This comes at the cost of a deceleration of the outer layer of the boundary layer. A detailed analysis of energy balances is presented, and a comparison is made between infinite and finite farm cases, for which boundary layer entrainment plays an import role. The authors acknowledge support from the European Research Council (FP7-Ideas, Grant No. 306471). Simulations were performed on the computing infrastructure of the VSC Flemish Supercomputer Center, funded by the Hercules Foundation and the Flemish Govern.

  17. Contribution of large scale coherence to wind turbine power: A large eddy simulation study in periodic wind farms

    Science.gov (United States)

    Chatterjee, Tanmoy; Peet, Yulia T.

    2018-03-01

    Length scales of eddies involved in the power generation of infinite wind farms are studied by analyzing the spectra of the turbulent flux of mean kinetic energy (MKE) from large eddy simulations (LES). Large-scale structures with an order of magnitude bigger than the turbine rotor diameter (D ) are shown to have substantial contribution to wind power. Varying dynamics in the intermediate scales (D -10 D ) are also observed from a parametric study involving interturbine distances and hub height of the turbines. Further insight about the eddies responsible for the power generation have been provided from the scaling analysis of two-dimensional premultiplied spectra of MKE flux. The LES code is developed in a high Reynolds number near-wall modeling framework, using an open-source spectral element code Nek5000, and the wind turbines have been modelled using a state-of-the-art actuator line model. The LES of infinite wind farms have been validated against the statistical results from the previous literature. The study is expected to improve our understanding of the complex multiscale dynamics in the domain of large wind farms and identify the length scales that contribute to the power. This information can be useful for design of wind farm layout and turbine placement that take advantage of the large-scale structures contributing to wind turbine power.

  18. Bi-Level Decentralized Active Power Control for Large-Scale Wind Farm Cluster

    DEFF Research Database (Denmark)

    Huang, Shengli; Wu, Qiuwei; Guo, Yifei

    2018-01-01

    This paper presents a bi-level decentralized active power control (DAPC) for a large-scale wind farm cluster, consisting of several wind farms for better active power dispatch. In the upper level, a distributed active power control scheme based on the distributed consensus is designed to achieve...... fair active power sharing among multiple wind farms, which generates the power reference for each wind farm. A distributed estimator is used to estimate the total available power of all wind farms. In the lower level, a centralized control scheme based on the Model Predictive Control (MPC) is proposed...... to regulate active power outputs of all wind turbines (WTs) within a wind farm, which reduces the fatigue loads of WTs while tracking the power reference obtained from the upper level control. A wind farm cluster with 8 wind farms and totally 160 WTs, was used to test the control performance of the proposed...

  19. Studies of Sub-Synchronous Oscillations in Large-Scale Wind Farm Integrated System

    Science.gov (United States)

    Yue, Liu; Hang, Mend

    2018-01-01

    With the rapid development and construction of large-scale wind farms and grid-connected operation, the series compensation wind power AC transmission is gradually becoming the main way of power usage and improvement of wind power availability and grid stability, but the integration of wind farm will change the SSO (Sub-Synchronous oscillation) damping characteristics of synchronous generator system. Regarding the above SSO problem caused by integration of large-scale wind farms, this paper focusing on doubly fed induction generator (DFIG) based wind farms, aim to summarize the SSO mechanism in large-scale wind power integrated system with series compensation, which can be classified as three types: sub-synchronous control interaction (SSCI), sub-synchronous torsional interaction (SSTI), sub-synchronous resonance (SSR). Then, SSO modelling and analysis methods are categorized and compared by its applicable areas. Furthermore, this paper summarizes the suppression measures of actual SSO projects based on different control objectives. Finally, the research prospect on this field is explored.

  20. Evaluation of wind farm efficiency and wind turbine wakes at the Nysted offshore wind farm

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Jensen, L.E.

    2010-01-01

    Here, we quantify relationships between wind farm efficiency and wind speed, direction, turbulence and atmospheric stability using power output from the large offshore wind farm at Nysted in Denmark. Wake losses are, as expected, most strongly related to wind speed variations through the turbine...... thrust coefficient; with direction, atmospheric stability and turbulence as important second order effects. While the wind farm efficiency is highly dependent on the distribution of wind speeds and wind direction, it is shown that the impact of turbine spacing on wake losses and turbine efficiency can...... be quantified, albeit with relatively large uncertainty due to stochastic effects in the data. There is evidence of the ‘deep array effect’ in that wake losses in the centre of the wind farm are under-estimated by the wind farm model WAsP, although overall efficiency of the wind farm is well predicted due...

  1. Automatic Voltage Control System with Market Price Employing Large Wind Farms

    DEFF Research Database (Denmark)

    Qin, Nan; Bak, Claus Leth; Abildgaard, Hans

    2018-01-01

    of the voltage control service provided by the power plant owners. The benefit of employing the large offshore wind farms in this AVC system is investigated. The simulation based on the measurement data from the Danish electricity control center demonstrates the superiority of the proposed approach in terms...... of the cost minimization. The gained profit by employing the wind farms can be an argument to purchase the voltage control service provided by these wind farms....

  2. Optimal Selection of AC Cables for Large Scale Offshore Wind Farms

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Zhe

    2014-01-01

    The investment of large scale offshore wind farms is high in which the electrical system has a significant contribution to the total cost. As one of the key components, the cost of the connection cables affects the initial investment a lot. The development of cable manufacturing provides a vast...... and systematical way for the optimal selection of cables in large scale offshore wind farms....

  3. Modelling and measurements of wakes in large wind farms

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Rathmann, Ole; Frandsen, Sten Tronæs

    2007-01-01

    The paper presents research conducted in the Flow workpackage of the EU funded UPWIND project which focuses on improving models of flow within and downwind of large wind farms in complex terrain and offshore. The main activity is modelling the behaviour of wind turbine wakes in order to improve...

  4. Modelization of a large wind farm, considering the modification of the atmospheric boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, A; Gomez-Elvira, R [Univ. Politecnica de Madrid, Mecanica de Fluidos, E.T.S.I. Industriales, Madrid (Spain); Frandsen, S; Larsen, S E [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    A method is presented to adapt existing models of wind farms to very large ones that may affect the whole planetary boundary layer. An internal boundary layer is considered that starts developing at the leading edge of the farm until it reaches, sufficiently far downstream, the top of the planetary boundary layer, and a new equilibrium region is reached. The wind farm is simulated by an artificial roughness that is function of the turbine spacing, drag and height. From this model the flow conditions are calculated at a certain reference height and then are used as boundary conditions for a numerical code used to model a wind farm. Three-dimensional effects are considered by applying appropriate conditions at the sides of the farm. Calculations are carried out to estimate the energy production in large wind farms, and it is found that additional losses due to modification of the planetary boundary layer may be of importance for wind farms of size larger than about 100 km. (au)

  5. Impacts of large-scale offshore wind farm integration on power systems through VSC-HVDC

    DEFF Research Database (Denmark)

    Liu, Hongzhi; Chen, Zhe

    2013-01-01

    The potential of offshore wind energy has been commonly recognized and explored globally. Many countries have implemented and planned offshore wind farms to meet their increasing electricity demands and public environmental appeals, especially in Europe. With relatively less space limitation......, an offshore wind farm could have a capacity rating to hundreds of MWs or even GWs that is large enough to compete with conventional power plants. Thus the impacts of a large offshore wind farm on power system operation and security should be thoroughly studied and understood. This paper investigates...... the impacts of integrating a large-scale offshore wind farm into the transmission system of a power grid through VSC-HVDC connection. The concerns are focused on steady-state voltage stability, dynamic voltage stability and transient angle stability. Simulation results based on an exemplary power system...

  6. Modelling and measurements of wakes in large wind farms

    International Nuclear Information System (INIS)

    Barthelmie, R J; Rathmann, O; Frandsen, S T; Hansen, K S; Politis, E; Prospathopoulos, J; Rados, K; Cabezon, D; Schlez, W; Phillips, J; Neubert, A; Schepers, J G; Pijl, S P van der

    2007-01-01

    The paper presents research conducted in the Flow workpackage of the EU funded UPWIND project which focuses on improving models of flow within and downwind of large wind farms in complex terrain and offshore. The main activity is modelling the behaviour of wind turbine wakes in order to improve power output predictions

  7. Can Weather Radars Help Monitoring and Forecasting Wind Power Fluctuations at Large Offshore Wind Farms?

    DEFF Research Database (Denmark)

    Trombe, Pierre-Julien; Pinson, Pierre; Madsen, Henrik

    2011-01-01

    The substantial impact of wind power fluctuations at large offshore wind farms calls for the development of dedicated monitoring and prediction approaches. Based on recent findings, a Local Area Weather Radar (LAWR) was installed at Horns Rev with the aim of improving predictability, controlability...... and potentially maintenance planning. Additional images are available from a Doppler radar covering the same area. The parallel analysis of rain events detection and of regime sequences in wind (and power) fluctuations demonstrates the interest of employing weather radars for a better operation and management...... of offshore wind farms....

  8. Flow and wakes in large wind farms: Final report for UpWind WP8

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Frandsen, Sten Tronæs; Rathmann, Ole

    This report summarises the research undertaken through the European Commission funded project UpWind Wp8:Flow. The objective of the work was to develop understanding of flow in large wind farms and to evaluate models of power losses due to wind turbine wakes focusing on complex terrain and offshore...

  9. Offshore Wind Farms

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Hasager, Charlotte Bay; Courtney, Michael

    2015-01-01

    : the rotor, the nacelle, the tower, and the foundation. Further the determinations of the essential environmental conditions are treated: the wind field, the wave field, the sea current, and the soil conditions. The various options for grid connections, advantages, and disadvantages are discussed. Of special...... concern are the problems associated with locating the turbines close together in a wind farm and the problems of placing several large wind farms in a confined area. The environmental impacts of offshore wind farms are also treated, but not the supply chain, that is, the harbors, the installation vessels...

  10. Summary Report: The Shadow effect of large wind farms: measurements, data analysis and modelling

    DEFF Research Database (Denmark)

    Frandsen, Sten Tronæs; Barthelmie, Rebecca Jane; Rathmann, Ole

    It was the goal of the project – by means of data from the demonstration wind farms Horns Rev and Nysted, analyses of these data and modelling – to facilitate prediction of the power losses from a wind farm should a new wind farm be built upwind relative to the prevailing wind direction...... it may appropriate to build new wind farms rather close to the existing wind farms. A relevant question is therefore how far away new wind farms must be placed to avoid too large power losses. Measurements have been carried out for several years at the two sites, and databases have been prepared....... Thus, if different modelling efforts results in comparable results, the quality of the models will be tested outside the physical range where data are available. All considered the project participants find that the project has been immensely successful. The main achievements of the project are...

  11. Design Performance Standards for Large Scale Wind Farms

    DEFF Research Database (Denmark)

    Gordon, Mark

    2009-01-01

    of connection into the Eastern Australian power system under the Rules and guidelines set out by AEMC and NEMMCO (AEMO). Where applicable some international practices are also mentioned. Standards are designed to serve as a technical envelope under which wind farm proponents design the plant and maintain...... ongoing technical compliance of the plant during its operational lifetime. This report is designed to provide general technical information for the wind farm connection engineer to be aware of during the process of connection, registration and operation of wind power plants interconnected into the HV TSO......’s network. No special NER Rule has been used in this document, however V30 (year 2009) has been used as the latest reference on some of the topics discussed. Care has been taken to emphasise certain wind farm design and connection issues that could be considered throughout different stages of the wind farm...

  12. Experimental study of the impact of large-scale wind farms on land–atmosphere exchanges

    International Nuclear Information System (INIS)

    Zhang Wei; Markfort, Corey D; Porté-Agel, Fernando

    2013-01-01

    Large-scale wind farms, covering a significant portion of the land and ocean surface, may affect the transport of momentum, heat, mass and moisture between the atmosphere and the land locally and globally. To understand the wind-farm–atmosphere interaction, we conducted wind-tunnel experiments to study the surface scalar (heat) flux using model wind farms, consisting of more than ten rows of wind turbines—having typical streamwise and spanwise spacings of five and four rotor diameters—in a neutral boundary layer with a heated surface. The spatial distribution of the surface heat flux was mapped with an array of surface heat flux sensors within the quasi-developed regime of the wind-farm flow. Although the overall surface heat flux change produced by the wind farms was found to be small, with a net reduction of 4% for a staggered wind farm and nearly zero change for an aligned wind farm, the highly heterogeneous spatial distribution of the surface heat flux, dependent on the wind-farm layout, was significant. The difference between the minimum and maximum surface heat fluxes could be up to 12% and 7% in aligned and staggered wind farms, respectively. This finding is important for planning intensive agriculture practice and optimizing farm land use strategy regarding wind energy project development. The well-controlled wind-tunnel experiments presented in this study also provide a first comprehensive dataset on turbulent flow and scalar transport in wind farms, which can be further used to develop and validate new parameterizations of surface scalar fluxes in numerical models. (letter)

  13. Operation and control of large wind turbines and wind farms. Final report

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Hansen, Anca Daniela; Thomsen, Kenneth

    2005-01-01

    good power quality and limit mechanical loads and life time consumption. The projectdeveloped models for 3 different concepts for wind farms. Two of the concepts use active stall controlled wind turbines, one with AC connection and one with modern HVDC/VSC connection of the wind farm. The third concept...... is based on pitch controlled windturbines using doubly fed induction generators. The models were applied to simulate the behaviour of the wind farm control when they were connected to a strong grid, and some initial simulations were performed to study the behaviour of the wind farms whenit was isolated...... concepts. The potentials of optimising the lifetime/energy production ratio by means of using revised operational strategies for the individual wind turbines are investigated. Different strategies have beensimulated, where the power production is decreased to an optimum when taking loads and actual price...

  14. Probabilistic Aspects of Harmonic Emission of Large Offshore Wind Farms

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær; Bak, Claus Leth; Kocewiak, Lukasz Hubert

    2011-01-01

    In this article, a new probabilistic method of as-sessment of harmonic emission of large offshore wind farms is presented. Based on measurements from the British wind farm Burbo Banks, probability density functions are estimated for the dominating low order harmonic currents injected by a single...... turbine. The degree and type of dependence between the harmonic emission and the operating point of a single turbine is established. A model of Burbo Banks, suitable for harmonic load flow studies, is created in DIgSILENT Power Factory along with a DPL-script that deals with the probabilistic issues...... of the harmonic emission. The simulated harmonic distortion at the PCC is compared to measurement. This reveals some diffi-culties regarding harmonic load flow studies. The harmonic background distortion in the grid to where the wind farm is connected must be included in the study. Furthermore, a very detailed...

  15. Power Transmission from Large Offshore Wind Farms

    DEFF Research Database (Denmark)

    Pedersen, Jørgen Kaas

    1999-01-01

    The major part of the coming wind farms in Denmark will be placed offshore. If the location is near a grid with a high short circuit level the power can be transmitted as AC.If the wind farm is far away from the grid and the grid perhaps has a low short circuit level, the best solution...... for transmitting the power can be by DC. At the moment it is possible to build self-commutating DC/AC-inverters up to about 150 kV. This paper will show a concept to a solution for a wind farm and a transmission system based on synchronous generators or a powerformer® with a rated voltage of 50 kV. The AC power...... will be rectified and boosted to a fixed DC voltage (e.g. 100 kV). The speed of the generator will be variable, depending of the wind but also controlled with the duty-cycle of the booster. In that way all wind turbines can be connected to the same DC bus and the cable to the inverter station connected to the AC...

  16. Temporal structure of aggregate power fluctuations in large-eddy simulations of extended wind-farms

    NARCIS (Netherlands)

    Stevens, Richard Johannes Antonius Maria; Meneveau, Charles

    2014-01-01

    Fluctuations represent a major challenge for the incorporation of electric power from large wind-farms into power grids. Wind-farm power output fluctuates strongly in time, over various time scales. Understanding these fluctuations, especially their spatio-temporal characteristics, is particularly

  17. Probabilistic aspects of harmonic emission of large offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Christian F. [Energinet.dk, Fredericia (Denmark); Bak, Claus L. [Aalborg Univ. (Denmark). Dept. of Energy Technology; Kocewiak, Lukasz; Hjerrild, Jesper [DONG Energy, Skaerbaek (Denmark); Berthelsen, Kasper K. [Aalborg Univ. (Denmark). Dept. of Mathematical Sciences

    2011-07-01

    In this article, a new probabilistic method of assessment of harmonic emission of large offshore wind farms is presented. Based on measurements from the British wind farm Burbo Banks, probability density functions are estimated for the dominating low order harmonic currents injected by a single turbine. The degree and type of dependence between the harmonic emission and the operating point of a single turbine is established. A model of Burbo Banks, suitable for harmonic load flow studies, is created in DIgSILENT Power Factory along with a DPL-script that deals with the probabilistic issues of the harmonic emission. The simulated harmonic distortion at the PCC is compared to measurement. This reveals some difficulties regarding harmonic load flow studies. The harmonic background distortion in the grid to where the wind farms is connected must be included in the study. Furthermore, a very detailed representation of the frequency dependent short circuit impedance must be used before sufficiently accurate results can be obtained from the model. (orig.)

  18. TOPFARM wind farm optimization tool

    DEFF Research Database (Denmark)

    Réthoré, Pierre-Elouan; Fuglsang, Peter; Larsen, Torben J.

    A wind farm optimization framework is presented in detail and demonstrated on two test cases: 1) Middelgrunden and 2) Stags Holt/Coldham. A detailed flow model describing the instationary flow within a wind farm is used together with an aeroelastic model to determine production and fatigue loading...... of wind farm wind turbines. Based on generic load cases, the wind farm production and fatigue evaluations are subsequently condensed in a large pre-calculated database for rapid calculation of lifetime equivalent loads and energy production in the optimization loop.. The objective function defining....... The Middelgrunden test case resulted in an improvement of the financial balance of 2.1 M€ originating from a very large increase in the energy production value of 9.3 M€ mainly counterbalanced by increased electrical grid costs. The Stags Holt/Coldham test case resulted in an improvement of the financial balance...

  19. Equivalent models of wind farms by using aggregated wind turbines and equivalent winds

    International Nuclear Information System (INIS)

    Fernandez, L.M.; Garcia, C.A.; Saenz, J.R.; Jurado, F.

    2009-01-01

    As a result of the increasing wind farms penetration on power systems, the wind farms begin to influence power system, and therefore the modeling of wind farms has become an interesting research topic. In this paper, new equivalent models of wind farms equipped with wind turbines based on squirrel-cage induction generators and doubly-fed induction generators are proposed to represent the collective behavior on large power systems simulations, instead of using a complete model of wind farms where all the wind turbines are modeled. The models proposed here are based on aggregating wind turbines into an equivalent wind turbine which receives an equivalent wind of the ones incident on the aggregated wind turbines. The equivalent wind turbine presents re-scaled power capacity and the same complete model as the individual wind turbines, which supposes the main feature of the present equivalent models. Two equivalent winds are evaluated in this work: (1) the average wind from the ones incident on the aggregated wind turbines with similar winds, and (2) an equivalent incoming wind derived from the power curve and the wind incident on each wind turbine. The effectiveness of the equivalent models to represent the collective response of the wind farm at the point of common coupling to grid is demonstrated by comparison with the wind farm response obtained from the detailed model during power system dynamic simulations, such as wind fluctuations and a grid disturbance. The present models can be used for grid integration studies of large power system with an important reduction of the model order and the computation time

  20. The necessary distance between large wind farms offshore - study

    DEFF Research Database (Denmark)

    Frandsen, S.; Barthelmie, R.J.; Pryor, S.C.

    2005-01-01

    the new Storpark Analytical Model has been developed and evaluated. As it is often the need for offshore wind farms, the model handles a regular array-geometry with straight rows of wind turbines and equidistantspacing between units in each row and equidistant spacing between rows. Firstly, the case...... with the flow direction being parallel to rows in a rectangular geometry is considered by defining three flow regimes. Secondly, when the flow is not in line withthe main rows, solutions are found for the patterns of wind turbine units emerging corresponding to each wind direction. The model complex......A review of state of the art wake and boundary layer wind farms was conducted. The predictions made for wind recovery distances (that might be used to estimate optimal placing of neighbouring wind farms) range between 2 and 14 km. In order to model thelink between wakes and the boundary layer...

  1. The necessary distance between large wind farms offshore - study

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, S.; Barthelmie, R.; Pryor, S.; Rathmann, O.; Larsen, S.; Hoejstrup, J.; Nielsen, P.; Lybech Thoegersen, M.

    2004-08-01

    A review of state of the art wake and boundary layer wind farms was conducted. The predictions made for wind recovery distances (that might be used to estimate optimal placing of neighbouring wind farms) range between 2 and 14 km. In order to model the link between wakes and the boundary layer the new Storpark Analytical Model has been developed and evaluated. As it is often the need for offshore wind farms, the model handles a regular array-geometry with straight rows of wind turbines and equidistant spacing between units in each row and equidistant spacing between rows. Firstly, the case with the flow direction being parallel to rows in a rectangular geometry is considered by defining three flow regimes. Secondly, when the flow is not in line with the main rows, solutions are found for the patterns of wind turbine units emerging corresponding to each wind direction. The model complex will be adjusted and calibrated with measurements in the near future. (au)

  2. Wind farm production estimates

    DEFF Research Database (Denmark)

    Larsen, Torben J.; Larsen, Gunner Chr.; Aagaard Madsen, Helge

    2012-01-01

    In this paper, the Dynamic Wake Meandering (DWM) model is applied for simulation of wind farm production. In addition to the numerical simulations, measured data have been analyzed in order to provide the basis for a full-scale verification of the model performance. The basic idea behind the DWMm......In this paper, the Dynamic Wake Meandering (DWM) model is applied for simulation of wind farm production. In addition to the numerical simulations, measured data have been analyzed in order to provide the basis for a full-scale verification of the model performance. The basic idea behind...... the DWMmodel is to model the in- stationary wind farm flow characteristics by considering wind turbine wakes as passive tracers continuously emitted from the wind farm turbines each with a downstream transport pro- cess dictated by large scale turbulent eddies (lateral and ver- tical transportation; i.......e. meandering) and Taylor advection. For the present purpose, the DWM model has been im- plemented in the aeroelastic code HAWC2 [1], and the per- formance of the resulting model complex is mainly verified by comparing simulated and measured loads for the Dutch off-shore Egmond aan Zee wind farm [2]. This farm...

  3. Evaluation model of wind energy resources and utilization efficiency of wind farm

    Science.gov (United States)

    Ma, Jie

    2018-04-01

    Due to the large amount of abandoned winds in wind farms, the establishment of a wind farm evaluation model is particularly important for the future development of wind farms In this essay, consider the wind farm's wind energy situation, Wind Energy Resource Model (WERM) and Wind Energy Utilization Efficiency Model(WEUEM) are established to conduct a comprehensive assessment of the wind farm. Wind Energy Resource Model (WERM) contains average wind speed, average wind power density and turbulence intensity, which assessed wind energy resources together. Based on our model, combined with the actual measurement data of a wind farm, calculate the indicators using the model, and the results are in line with the actual situation. We can plan the future development of the wind farm based on this result. Thus, the proposed establishment approach of wind farm assessment model has application value.

  4. Wind farms and planning

    International Nuclear Information System (INIS)

    Arkesteijn, L.; Havinga, R.; Benner, J.H.B.

    1992-01-01

    The siting of wind farms is becoming an increasingly important issue in the Netherlands. This paper gives an overview of the current situation concerning the planning of wind farms. We will pay attention to: Wind energy in official Dutch planning policy. To select the optimal sites, the government has made an administrative agreement with the 7 windy provinces. Nevertheless, wind energy is still fighting for a rightful position in physical planning policy. Some examples will illustrate this. Studies on siting and siting problems in the Netherlands. In order to gain more insight into aspects of wind farming several studies have been executed. In this paper special attention will be paid to the results of a study on the potential impact of large windturbine clusters on an existing agricutural area. Experiences with siting of wind farms in the Netherlands. Based on experiences with the planning and realization of farms, this paper gives the main problems. In the final part of the paper we present some general conclusions. Generally speaking, the knowledge is available for selecting optimal sites in the Netherlands. The basic problems for wind farming nowadays seem to be the visual impact and actually obtaining the ground. Nevertheless, there do seem to be enough sites for realizing the goals in the Netherlands. (au)

  5. Using Satellite SAR to Characterize the Wind Flow around Offshore Wind Farms

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Vincent, Pauline; Badger, Jake

    2015-01-01

    Offshore wind farm cluster effects between neighboring wind farms increase rapidly with the large-scale deployment of offshore wind turbines. The wind farm wakes observed from Synthetic Aperture Radar (SAR) are sometimes visible and atmospheric and wake models are here shown to convincingly repro...

  6. Cost-efficient foundation structures for large offshore wind farms

    International Nuclear Information System (INIS)

    Birch, C.; Gormsen, C.; Lyngesen, S.; Rasmussen, J. L.; Juhl, H.

    1997-01-01

    This paper presents the results of the development of a cost-efficient foundation for large (1.5 MW) offshore wind farms at water depth of 5 to 11 m. Previously, medium sized wind turbines (500 kW) in Denmark have been installed offshore at water depths of approximately 5 m on concrete gravity foundations. The installation of larger turbines at greater depth does, however, hold great promise in terms of wind environment and environmental considerations. The costs of a traditional gravity foundation at these increased water depths is expected to be prohibitive, and the aim of the project has been to reduce the foundations costs in general. This paper describes the theoretical basis for the geotechnical and structural design of three alternative concepts and presents an optimised layout of each based on a research and development project. The basis has been a wind farm consisting of 100 turbines. The R and D project has been undertaken by the consulting engineers Nellemann, Nielsen and Rauschenberger A/S (Gravity foundation), LICengineering A/S (Mono pile) and Ramboell (Tripod) in co-operation with the Danish utility engineering companies Elkraft and Elsamprojekt A/S. The project was partly financed by the participants and by the Danish Energy Agency through their 1996 Energy Research Programme (EFP-96). (au) 18 refs

  7. Using Satellite SAR to Characterize the Wind Flow around Offshore Wind Farms

    Directory of Open Access Journals (Sweden)

    Charlotte Bay Hasager

    2015-06-01

    Full Text Available Offshore wind farm cluster effects between neighboring wind farms increase rapidly with the large-scale deployment of offshore wind turbines. The wind farm wakes observed from Synthetic Aperture Radar (SAR are sometimes visible and atmospheric and wake models are here shown to convincingly reproduce the observed very long wind farm wakes. The present study mainly focuses on wind farm wake climatology based on Envisat ASAR. The available SAR data archive covering the large offshore wind farms at Horns Rev has been used for geo-located wind farm wake studies. However, the results are difficult to interpret due to mainly three issues: the limited number of samples per wind directional sector, the coastal wind speed gradient, and oceanic bathymetry effects in the SAR retrievals. A new methodology is developed and presented. This method overcomes effectively the first issue and in most cases, but not always, the second. In the new method all wind field maps are rotated such that the wind is always coming from the same relative direction. By applying the new method to the SAR wind maps, mesoscale and microscale model wake aggregated wind-fields results are compared. The SAR-based findings strongly support the model results at Horns Rev 1.

  8. Wake characteristics of wind turbines in utility-scale wind farms

    Science.gov (United States)

    Yang, Xiaolei; Foti, Daniel; Sotiropoulos, Fotis

    2017-11-01

    The dynamics of turbine wakes is affected by turbine operating conditions, ambient atmospheric turbulent flows, and wakes from upwind turbines. Investigations of the wake from a single turbine have been extensively carried out in the literature. Studies on the wake dynamics in utility-scale wind farms are relatively limited. In this work, we employ large-eddy simulation with an actuator surface or actuator line model for turbine blades to investigate the wake dynamics in utility-scale wind farms. Simulations of three wind farms, i.e., the Horns Rev wind farm in Denmark, Pleasant Valley wind farm in Minnesota, and the Vantage wind farm in Washington are carried out. The computed power shows a good agreement with measurements. Analysis of the wake dynamics in the three wind farms is underway and will be presented in the conference. This work was support by Xcel Energy (RD4-13). The computational resources were provided by National Renewable Energy Laboratory.

  9. Impacts of a large array of offshore wind farms on precipitation during hurricane Harvey

    Science.gov (United States)

    Pan, Y.; Archer, C. L.

    2017-12-01

    Hurricane Harvey brought to the Texas coast possibly the heaviest rain ever recorded in U.S. history, which then caused flooding at unprecedented levels. Previous studies have shown that large arrays of offshore wind farms can extract kinetic energy from a hurricane and thus reduce the wind and storm surge. This study will quantitatively test weather the offshore turbines may also affect precipitation patterns. The Weather Research Forecast model is employed to model Harvey and the offshore wind farms are parameterized as elevated drag and turbulence kinetic energy sources. The turbines (7.8 MW Enercon-126 with rotor diameter D=127 m) are placed along the coast of Texas and Louisiana within 100 km from the shore, where the water depth is below 200 meters. Three spacing between turbines are considered (with the number of turbines in parenthesis): 7D×7D (149,936), 9D×9D (84,339), and 11D×11D (56,226). A fourth case (9D×9D) with a smaller area and thus less turbines (33,363) is added to the simulations to emphasize the impacts of offshore turbines installed specifically to protect the city of Houston, which was flooded heavily during hurricane Harvey. The model is integrated for 24 hours from 00UTC Aug 26th, 2017 to 00UTC Aug 27th, 2017. Model results indicate that the offshore wind farms have a strong impact on the distribution of 24-hour accumulated precipitation, with an obvious decrease onshore, downstream of the wind farms, and an increase in the offshore areas, upstream of or within the wind farms. A sector covering the metro-Houston area is chosen to study the sensitivity of the four different wind farm layouts. The spatial-average 24-hour accumulated precipitation is decreased by 37%, 28%, 20% and 25% respectively for the four cases. Compared with the control case with no wind turbines, increased horizontal wind divergence and lower vertical velocity are found where the precipitation is reduced onshore, whereas increased horizontal wind convergence and

  10. How neighbours of the first large Swiss wind farm perceive the wind turbines

    International Nuclear Information System (INIS)

    Droz, Y.; Mieville-Ott, V.; Monsutti, A.

    2003-01-01

    This report for the Swiss Federal Office of Energy presents the results of a study on the way the neighbours of the first large Swiss wind farm react on this particular neighbourhood. A survey involving 421 people showed that, as a general rule, the wind turbines are well accepted. However, it also showed that a transparent negotiation with the population during wind turbine project developpement is absolutely needed. Public acceptance also depends on the way the turbine arrays are aesthetically integrated in the landscape. The report is rounded up by recommendations for companies in charge of wind energy projects in order to minimize troubles with the concerned population. For example, financial compensation could be a suitable means when dealing with farmers

  11. Analytical Model for Mean Flow and Fluxes of Momentum and Energy in Very Large Wind Farms

    Science.gov (United States)

    Markfort, Corey D.; Zhang, Wei; Porté-Agel, Fernando

    2018-01-01

    As wind-turbine arrays continue to be installed and the array size continues to grow, there is an increasing need to represent very large wind-turbine arrays in numerical weather prediction models, for wind-farm optimization, and for environmental assessment. We propose a simple analytical model for boundary-layer flow in fully-developed wind-turbine arrays, based on the concept of sparsely-obstructed shear flows. In describing the vertical distribution of the mean wind speed and shear stress within wind farms, our model estimates the mean kinetic energy harvested from the atmospheric boundary layer, and determines the partitioning between the wind power captured by the wind turbines and that absorbed by the underlying land or water. A length scale based on the turbine geometry, spacing, and performance characteristics, is able to estimate the asymptotic limit for the fully-developed flow through wind-turbine arrays, and thereby determine if the wind-farm flow is fully developed for very large turbine arrays. Our model is validated using data collected in controlled wind-tunnel experiments, and its usefulness for the prediction of wind-farm performance and optimization of turbine-array spacing are described. Our model may also be useful for assessing the extent to which the extraction of wind power affects the land-atmosphere coupling or air-water exchange of momentum, with implications for the transport of heat, moisture, trace gases such as carbon dioxide, methane, and nitrous oxide, and ecologically important oxygen.

  12. Reliability, availability and maintenance aspects of large-scale offshore wind farms, a concepts study

    NARCIS (Netherlands)

    Van Bussel, G.J.W.; Zaayer, M.B.

    2001-01-01

    The DOWEC projects aims at implementation of large wind turbines in large scale wind farms. part of the DOWEC project a concepts study was performed regarding the achievable reliability and availability levels. A reduction with a factor of 2 with regard to the present state of the art seems fairly

  13. Wind power forecast error smoothing within a wind farm

    International Nuclear Information System (INIS)

    Saleck, Nadja; Bremen, Lueder von

    2007-01-01

    Smoothing of wind power forecast errors is well-known for large areas. Comparable effects within a wind farm are investigated in this paper. A Neural Network was taken to predict the power output of a wind farm in north-western Germany comprising 17 turbines. A comparison was done between an algorithm that fits mean wind and mean power data of the wind farm and a second algorithm that fits wind and power data individually for each turbine. The evaluation of root mean square errors (RMSE) shows that relative small smoothing effects occur. However, it can be shown for this wind farm that individual calculations have the advantage that only a few turbines are needed to give better results than the use of mean data. Furthermore different results occurred if predicted wind speeds are directly fitted to observed wind power or if predicted wind speeds are first fitted to observed wind speeds and then applied to a power curve. The first approach gives slightly better RMSE values, the bias improves considerably

  14. Integration of a wind farm with a wave- and an aquaculture farm

    OpenAIRE

    He, J.; Weissenberger, J.; Bergh, Øivind; Hjøllo, Solfrid Sætre; Wehde, Henning; Agnalt, Ann-Lisbeth; Chen, Z.; Olason, D.; Thorsteinson, B.; Fosso, O.B.

    2011-01-01

    There is a growing interest in placing wind farms offshore. 140 GW of offshore wind are currently being planned to reach the EU energy 2020 goal. However, an offshore wind farm occupies a large area and competes with other users of the maritime space. The integration of an offshore wind farm with other marine energy producers such as wave energy and other maritime users such as aquaculture farms may result in significant benefits in terms of economics, optimising spatial utilization, and mini...

  15. Modelling and transient stability of large wind farms

    DEFF Research Database (Denmark)

    Akhmatov, Vladislav; Knudsen, Hans; Nielsen, Arne Hejde

    2003-01-01

    by a physical model of grid-connected windmills. The windmill generators ate conventional induction generators and the wind farm is ac-connected to the power system. Improvements-of short-term voltage stability in case of failure events in the external power system are treated with use of conventional generator...... technology. This subject is treated as a parameter study with respect to the windmill electrical and mechanical parameters and with use of control strategies within the conventional generator technology. Stability improvements on the wind farm side of the connection point lead to significant reduction...

  16. Challenges in wind farm optimization

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.

    To achieve the optimal economic output from a wind farm over its lifetime, an optimal balance between capital costs, operation and maintenance costs, fatigue lifetime consumption of turbine components and power production is to be determined on a rational basis. This has implications both...... for the wind turbine modeling, where aeroelastic models are required, and for the wind farm flow field description, where in-stationary flow field modeling is needed to capture the complicated mixture of atmospheric boundary layer (ABL) flows and upstream emitted meandering wind turbine wakes, which together...... dictates the fatigue loading of the individual wind turbines. Within an optimization context, the basic challenge in describing the in-stationary wind farm flow field is computational speed. The Dynamic Wake Meandering (DWM) model includes the basic features of a CFD Large Eddy Simulation approach...

  17. On wake modeling, wind-farm gradients, and AEP predictions at the Anholt wind farm

    Directory of Open Access Journals (Sweden)

    A. Peña

    2018-04-01

    Full Text Available We investigate wake effects at the Anholt offshore wind farm in Denmark, which is a farm experiencing strong horizontal wind-speed gradients because of its size and proximity to land. Mesoscale model simulations are used to study the horizontal wind-speed gradients over the wind farm. From analysis of the mesoscale simulations and supervisory control and data acquisition (SCADA, we show that for westerly flow in particular, there is a clear horizontal wind-speed gradient over the wind farm. We also use the mesoscale simulations to derive the undisturbed inflow conditions that are coupled with three commonly used wake models: two engineering approaches (the Park and G. C. Larsen models and a linearized Reynolds-averaged Navier–Stokes approach (Fuga. The effect of the horizontal wind-speed gradient on annual energy production estimates is not found to be critical compared to estimates from both the average undisturbed wind climate of all turbines' positions and the undisturbed wind climate of a position in the middle of the wind farm. However, annual energy production estimates can largely differ when using wind climates at positions that are strongly influenced by the horizontal wind-speed gradient. When looking at westerly flow wake cases, where the impact of the horizontal wind-speed gradient on the power of the undisturbed turbines is largest, the wake models agree with the SCADA fairly well; when looking at a southerly flow case, where the wake losses are highest, the wake models tend to underestimate the wake loss. With the mesoscale-wake model setup, we are also able to estimate the capacity factor of the wind farm rather well when compared to that derived from the SCADA. Finally, we estimate the uncertainty of the wake models by bootstrapping the SCADA. The models tend to underestimate the wake losses (the median relative model error is 8.75 % and the engineering wake models are as uncertain as Fuga. These results are specific for

  18. Wind farm - A power source in future power systems

    DEFF Research Database (Denmark)

    Chen, Zhe; Blaabjerg, Frede

    2009-01-01

    wind turbines and wind farms, and then introduces the wind power development and wind farms. An optimization platform for designing electrical systems of offshore wind farms is briefed. The major issues related to the grid connection requirements and the operation of wind turbines/farms in power......The paper describes modern wind power systems, introduces the issues of large penetration of wind power into power systems, and discusses the possible methods of making wind turbines/farms act as a power source, like conventional power plants in power systems. Firstly, the paper describes modern...... systems are illustrated....

  19. TOPFARM wind farm optimization tool

    Energy Technology Data Exchange (ETDEWEB)

    Rethore, P.-E.; Fuglsang, P.; Larsen, Torben J.; Buhl, T.; Larsen, Gunner C.

    2011-02-15

    A wind farm optimization framework is presented in detail and demonstrated on two test cases: 1) Middelgrunden and 2) Stags Holt/Coldham. A detailed flow model describing the instationary flow within a wind farm is used together with an aeroelastic model to determine production and fatigue loading of wind farm wind turbines. Based on generic load cases, the wind farm production and fatigue evaluations are subsequently condensed in a large pre-calculated database for rapid calculation of lifetime equivalent loads and energy production in the optimization loop. The objective function defining the optimization problem includes elements as energy production, turbine degradation, operation and maintenance costs, electrical grid costs and foundation costs. The objective function is optimized using a dedicated multi fidelity approach with the locations of individual turbines in the wind farm spanning the design space. The results are over all satisfying and are giving some interesting insights on the pros and cons of the design choices. They show in particular that the inclusion of the fatigue loads costs give rise to some additional details in comparison with pure power based optimization. The Middelgrunden test case resulted in an improvement of the financial balance of 2.1 M Euro originating from a very large increase in the energy production value of 9.3 M Euro mainly counterbalanced by increased electrical grid costs. The Stags Holt/Coldham test case resulted in an improvement of the financial balance of 3.1 M Euro. (Author)

  20. Harmonics in large offshore wind farms

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert

    and nature of various harmonic components. A comprehensive comparison of harmonic voltages and currents based on probability distribution estimation and appropriate statistics calculation (mean, variance, probability density function, etc.) is applied. Such approach gives a better overview and comparison...... and analysis, and ϐinally ending up on modelling and models application. Different aspects of validation in time domain, frequency domain, and by application of statistical methods are mentioned in relation to respective problems. Measurements constitute a core part in industry-oriented research. Due...... that it is of great importance to know the nature of generated harmonics in large offshore wind farms in order to apply the most suitable data processing technique. Time-frequency analysis based on multiresolution wavelet transform is used in order to perform time-frequency domain analysis helpful to distinguish...

  1. Offshore Wind Farm Clusters - Towards new integrated Design Tool

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Réthoré, Pierre-Elouan; Peña, Alfredo

    In EERA DTOC testing of existing wind farm wake models against four validation data test sets from large offshore wind farms is carried out. This includes Horns Rev-1 in the North Sea, Lillgrund in the Baltic Sea, Roedsand-2 in the Baltic Sea and from 10 large offshore wind farms in Northern Euro...

  2. Simulations of an Offshore Wind Farm Using Large-Eddy Simulation and a Torque-Controlled Actuator Disc Model

    Science.gov (United States)

    Creech, Angus; Früh, Wolf-Gerrit; Maguire, A. Eoghan

    2015-05-01

    We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the Øresund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a large-eddy simulation CFD solver and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large-scale flow structures around the wind farm, and the local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates the interaction between the wind, the turbine rotors, and the turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would be fully aligned with the wind or at specific angles to the wind. Results shown here include presentations of the spin-up of turbines, the observation of eddies moving through the turbine array, meandering turbine wakes, and an extensive wind farm wake several kilometres in length. The key measurement available for cross-validation with operational wind farm data is the power output from the individual turbines, where the effect of unsteady turbine wakes on the performance of downstream turbines was a main point of interest. The results from the simulations were compared to the performance measurements from the real wind farm to provide a firm quantitative validation of this methodology. Having achieved good agreement between the model results and actual wind farm measurements, the potential of the methodology to provide a tool for further investigations of engineering and atmospheric science problems is outlined.

  3. Aggregated Modelling for Wind Farms for Power System Transient Stability Studies

    DEFF Research Database (Denmark)

    Liu, Hongzhi; Chen, Zhe

    2012-01-01

    Wind energy is consistently attracting great research effort and actively developed in many countries. As a result, the penetration level of wind power in the power grid is increasing as well as the size of wind farms. A large-scale wind farm may consist of hundreds of wind turbines and its total...... on a wind farm with permanent magnet synchronous generator (PMSG) wind turbines. Simulation results of the aggregated models and the detailed model are compared and analyzed respectively to prove the effectiveness of the aggregating techniques.......Wind energy is consistently attracting great research effort and actively developed in many countries. As a result, the penetration level of wind power in the power grid is increasing as well as the size of wind farms. A large-scale wind farm may consist of hundreds of wind turbines and its total...... installed capacity could be at a level of 1000MW or even more. Consequently, the large-scale wind farm could seriously impact the operation and control of the grid. To represent a large-scale wind farm, aggregated modelling takes advantage of fast computation and simplified implementation compared...

  4. Feasibility study on the wind farm; Wind farm no kanosei chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For assessment of the possibility of the wind farm (collective wind power facility) in Japan, site conditions, business plans and various issues in development were arranged using some projects in a planning stage. The case study of a system design was also conducted for a typical site. Four sites were selected based on geographical conditions, topographic features and weather conditions. Scales of every site are as large as 1000-3000kW and 400- 750kW in wind turbine capacity. Every developer expects a subsidy, and governmental economic support is indispensable for the wind farm. In the case of Hisai city, Mie prefecture with the most favorable wind condition in Japan, the annual mean wind velocity of the site is valued at nearly 8m/s, suggesting that it is promising for the wind farm. From the planned scale of 750kWtimes4, the annual generated power and availability factor are valued at 9,800,000kWh/y and 37%, respectively. From the construction cost of 1 billion yen including a subsidy of its half, the generation cost is valued at 14.5 yen/kWh in durability of 15 years, and 12.2 yen/kWh in 20 years, and the profitability is dependent on the purchase price of a power company. 27 figs., 36 tabs.

  5. CleverFarm - A SuperSCADA system for wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Giebel, G [ed.; Juhl, A; Gram Hansen, K; Biebhardt, J [and others

    2004-08-01

    The CleverFarm project started out to build an integrated monitoring system for wind farms, where all information would be available and could be used across the wind farm for maintenance and component health assessments. This would enable wind farm operators to prioritise their efforts, since they have a good view of the farm status from home. A large emphasis was placed on the integration of condition monitoring approaches in the central system, enabling estimates of the remaining lifetime of components, especially in the nacelle. During the 3,5 years of the project, software and hardware was developed and installed in two wind farms in Denmark and Germany. The connected hardware included two different condition monitoring systems based on vibration sensors from Gram&Juhl and ISET, plus a camera system developed by Overspeed. Additionally, short-term predictions of the wind farm output were delivered by DMI and Risoes Prediktor system throughout the period of the project. All these diverse information sources are integrated through a web interface based on Java Server Pages. The software was developed in Java, and is delivered as so-called CleverBeans. The main part of the software is open-sourced. The report contains the experiences and results of a one-year experimental period. This report is a slightly edited version of the final publishable report to the EU Commission as part of the requirements of the CleverFarm project.

  6. Modelling and Measuring Flow and Wind Turbine Wakes in Large Wind Farms Offshore

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Hansen, Kurt Schaldemose; Frandsen, Sten Tronæs

    2009-01-01

    power losses due to wakes and loads. The research presented is part of the EC-funded UpWind project, which aims to radically improve wind turbine and wind farm models in order to continue to improve the costs of wind energy. Reducing wake losses, or even reduce uncertainties in predicting power losses...

  7. Quantifying the Impact of Wind Turbine Wakes on Power Output at Offshore Wind Farms

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Pryor, Sara; Frandsen, Sten Tronæs

    2010-01-01

    There is an urgent need to develop and optimize tools for designing large wind farm arrays for deployment offshore. This research is focused on improving the understanding of, and modeling of, wind turbine wakes in order to make more accurate power output predictions for large offshore wind farms...

  8. In situ observations of the influence of a large onshore wind farm on near-surface temperature, turbulence intensity and wind speed profiles

    Science.gov (United States)

    Smith, Craig M.; Barthelmie, R. J.; Pryor, S. C.

    2013-09-01

    Observations of wakes from individual wind turbines and a multi-megawatt wind energy installation in the Midwestern US indicate that directly downstream of a turbine (at a distance of 190 m, or 2.4 rotor diameters (D)), there is a clear impact on wind speed and turbulence intensity (TI) throughout the rotor swept area. However, at a downwind distance of 2.1 km (26 D downstream of the closest wind turbine) the wake of the whole wind farm is not evident. There is no significant reduction of hub-height wind speed or increase in TI especially during daytime. Thus, in high turbulence regimes even very large wind installations may have only a modest impact on downstream flow fields. No impact is observable in daytime vertical potential temperature gradients at downwind distances of >2 km, but at night the presence of the wind farm does significantly decrease the vertical gradients of potential temperature (though the profile remains stably stratified), largely by increasing the temperature at 2 m.

  9. In situ observations of the influence of a large onshore wind farm on near-surface temperature, turbulence intensity and wind speed profiles

    International Nuclear Information System (INIS)

    Smith, Craig M; Barthelmie, R J; Pryor, S C

    2013-01-01

    Observations of wakes from individual wind turbines and a multi-megawatt wind energy installation in the Midwestern US indicate that directly downstream of a turbine (at a distance of 190 m, or 2.4 rotor diameters (D)), there is a clear impact on wind speed and turbulence intensity (TI) throughout the rotor swept area. However, at a downwind distance of 2.1 km (26 D downstream of the closest wind turbine) the wake of the whole wind farm is not evident. There is no significant reduction of hub-height wind speed or increase in TI especially during daytime. Thus, in high turbulence regimes even very large wind installations may have only a modest impact on downstream flow fields. No impact is observable in daytime vertical potential temperature gradients at downwind distances of >2 km, but at night the presence of the wind farm does significantly decrease the vertical gradients of potential temperature (though the profile remains stably stratified), largely by increasing the temperature at 2 m. (letter)

  10. A large-eddy simulation based power estimation capability for wind farms over complex terrain

    Science.gov (United States)

    Senocak, I.; Sandusky, M.; Deleon, R.

    2017-12-01

    There has been an increasing interest in predicting wind fields over complex terrain at the micro-scale for resource assessment, turbine siting, and power forecasting. These capabilities are made possible by advancements in computational speed from a new generation of computing hardware, numerical methods and physics modelling. The micro-scale wind prediction model presented in this work is based on the large-eddy simulation paradigm with surface-stress parameterization. The complex terrain is represented using an immersed-boundary method that takes into account the parameterization of the surface stresses. Governing equations of incompressible fluid flow are solved using a projection method with second-order accurate schemes in space and time. We use actuator disk models with rotation to simulate the influence of turbines on the wind field. Data regarding power production from individual turbines are mostly restricted because of proprietary nature of the wind energy business. Most studies report percentage drop of power relative to power from the first row. There have been different approaches to predict power production. Some studies simply report available wind power in the upstream, some studies estimate power production using power curves available from turbine manufacturers, and some studies estimate power as torque multiplied by rotational speed. In the present work, we propose a black-box approach that considers a control volume around a turbine and estimate the power extracted from the turbine based on the conservation of energy principle. We applied our wind power prediction capability to wind farms over flat terrain such as the wind farm over Mower County, Minnesota and the Horns Rev offshore wind farm in Denmark. The results from these simulations are in good agreement with published data. We also estimate power production from a hypothetical wind farm in complex terrain region and identify potential zones suitable for wind power production.

  11. Solving the Turbine Positioning Problem for Large Offshore Wind Farms by Simulated Annealing

    DEFF Research Database (Denmark)

    Rivas, Rajai Aghabi; Clausen, Jens; Hansen, Kurt Schaldemose

    2009-01-01

    search operations are performed recursively until the system converges. The effectiveness of the proposed algorithm is demonstrated on a suite of real life test cases, including Horns Rev offshore wind farm. The results are verified using a commercial wind resource software indicating that this method...... is negligible while, as the wind farm's size reduces, the differences start becoming significant. A sensitivity analysis is also performed showing that greater density of turbines in the perimeter of the optimized wind farm reduces the wake losses even if the wind climate changes....

  12. Maximum Energy Yield Oriented Turbine Control in PMSG based Wind Farm

    OpenAIRE

    Tian, Jie; Zhou, Dao; Su, Chi; Blaabjerg, Frede; Chen, Zhe

    2017-01-01

    : In the modern power systems, with the fast integration of the wind power into the grid, it turns to develop large-scale offshore wind farms equipped with the permanent magnet synchronous generator (PMSG) wind turbine. In large-scale offshore wind farms, the wind turbine operating reliability and the wake effect in the wind farm became important issues. The pitch angle and tip speed ratio are the two degrees of freedom for the PMSG wind turbine active power control, which are also the determ...

  13. Design tool for offshore wind farm cluster planning

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Madsen, Peter Hauge; Giebel, Gregor

    2015-01-01

    In the framework of the FP7 project EERA DTOC: Design Tool for Offshore wind farm Cluster, a new software supporting the planning of offshore wind farms was developed, based on state-of-the-art approaches from large scale wind potential to economic benchmarking. The model portfolio includes WAs......P, FUGA, WRF, Net-Op, LCoE model, CorWind, FarmFlow, EeFarm and grid code compliance calculations. The development is done by members from European Energy Research Alliance (EERA) and guided by several industrial partners. A commercial spin-off from the project is the tool ‘Wind & Economy’. The software...... by the software and several tests were performed. The calculations include the smoothing effect on produced energy between wind farms located in different regional wind zones and the short time scales relevant for assessing balancing power. The grid code compliance was tested for several cases and the results...

  14. Optimized Placement of Wind Turbines in Large-Scale Offshore Wind Farm using Particle Swarm Optimization Algorithm

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Soltani, Mohsen

    2015-01-01

    With the increasing size of wind farm, the impact of the wake effect on wind farm energy yields become more and more evident. The arrangement of the wind turbines’ (WT) locations will influence the capital investment and contribute to the wake losses which incur the reduction of energy production....... As a consequence, the optimized placement of the wind turbines may be done by considering the wake effect as well as the components cost within the wind farm. In this paper, a mathematical model which includes the variation of both wind direction and wake deficit is proposed. The problem is formulated by using...... Levelized Production Cost (LPC) as the objective function. The optimization procedure is performed by Particle Swarm Optimization (PSO) algorithm with the purpose of maximizing the energy yields while minimizing the total investment. The simulation results indicate that the proposed method is effective...

  15. Dynamic Strategies for Yaw and Induction Control of Wind Farms Based on Large-Eddy Simulation and Optimization

    Directory of Open Access Journals (Sweden)

    Wim Munters

    2018-01-01

    Full Text Available In wind farms, wakes originating from upstream turbines cause reduced energy extraction and increased loading variability in downstream rows. The prospect of mitigating these detrimental effects through coordinated controllers at the wind-farm level has fueled a multitude of research efforts in wind-farm control. The main strategies in wind-farm control are to influence the velocity deficits in the wake by deviating from locally optimal axial induction setpoints on the one hand, and steering wakes away from downstream rows through yaw misalignment on the other hand. The current work investigates dynamic induction and yaw control of individual turbines for wind-farm power maximization in large-eddy simulations. To this end, receding-horizon optimal control techniques combined with continuous adjoint gradient evaluations are used. We study a 4 × 4 aligned wind farm, and find that for this farm layout yaw control is more effective than induction control, both for uniform and turbulent inflow conditions. Analysis of optimal yaw controls leads to the definition of two simplified yaw control strategies, in which wake meandering and wake redirection are exploited respectively. Furthermore it is found that dynamic yawing provides significant benefits over static yaw control in turbulent flow environments, whereas this is not the case for uniform inflow. Finally, the potential of combining overinductive axial induction control with yaw control is shown, with power gains that approximate the sum of those achieved by each control strategy separately.

  16. Life cycle assessment of offshore and onshore sited wind farms

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-10-15

    This report makes up the final reporting for the project 'Life cycle assessment (LCA) of turbines Analysis of possibilities of product directed environmental optimisation'. The purpose of the project is to carry through a life cycle assessment of an offshore wind farm and an onshore wind farm, respectively, as a basis for assessment of environmental improvement possibilities for wind farms through their life cycles. Likewise, the results are used to elaborate an environmental declaration of contents for power delivered to the grid from both types of wind farms. The project states the environmental impact for electricity produced at Horns Reef offshore wind farm and Tjaereborg onshore wind farm, respectively, as representatives for contemporary Danish offshore wind farms and onshore wind farms, respectively. Tjaereborg onshore wind farm is placed at an utmost favourably location with regard to wind, which means that the production at this wind farm is high compared with other onshore wind farms in Denmark. The high production rate is a factor that is taken into account when assessing the impact on the environment emanating from this wind farm. The results of the environmental life cycle assessments that have been carried out for the two wind farms do not show significant variance. If it is taken into account that Tjaereborg onshore wind farm is placed utmost favourably, the comparison shows that power from an average located onshore wind farm would have a more adverse or corresponding environmental impact as an unfavourably located offshore wind farm. The results show that it is the turbines that causes the largest environmental impact and not to a very high extent the transmission grid. For the turbines, the all-important environmental contribution comes from manufacturing and removal of the turbines, as it is the materials that cause the large environmental strain. The operation of the wind farms gives practically no contribution to the total

  17. ANEMOS: Development of a next generation wind power forecasting system for the large-scale integration of onshore and offshore wind farms.

    Science.gov (United States)

    Kariniotakis, G.; Anemos Team

    2003-04-01

    Objectives: Accurate forecasting of the wind energy production up to two days ahead is recognized as a major contribution for reliable large-scale wind power integration. Especially, in a liberalized electricity market, prediction tools enhance the position of wind energy compared to other forms of dispatchable generation. ANEMOS, is a new 3.5 years R&D project supported by the European Commission, that resembles research organizations and end-users with an important experience on the domain. The project aims to develop advanced forecasting models that will substantially outperform current methods. Emphasis is given to situations like complex terrain, extreme weather conditions, as well as to offshore prediction for which no specific tools currently exist. The prediction models will be implemented in a software platform and installed for online operation at onshore and offshore wind farms by the end-users participating in the project. Approach: The paper presents the methodology of the project. Initially, the prediction requirements are identified according to the profiles of the end-users. The project develops prediction models based on both a physical and an alternative statistical approach. Research on physical models gives emphasis to techniques for use in complex terrain and the development of prediction tools based on CFD techniques, advanced model output statistics or high-resolution meteorological information. Statistical models (i.e. based on artificial intelligence) are developed for downscaling, power curve representation, upscaling for prediction at regional or national level, etc. A benchmarking process is set-up to evaluate the performance of the developed models and to compare them with existing ones using a number of case studies. The synergy between statistical and physical approaches is examined to identify promising areas for further improvement of forecasting accuracy. Appropriate physical and statistical prediction models are also developed for

  18. Empirical investigation of wind farm blockage effects in Horn Rev 1 offshore wind farm

    DEFF Research Database (Denmark)

    Mitraszewski, Karol; Hansen, Kurt Schaldemose; Nygaard, Nicolai

    We present an empirical study of wind farm blockage effects based on Horns Rev 1 SCADA data. The mean inflow non-uniformities in wind speed are analyzed by calculating the mean power outputs of turbines located along the outer edges of the farm for different wind directions, wind speeds and stabi......We present an empirical study of wind farm blockage effects based on Horns Rev 1 SCADA data. The mean inflow non-uniformities in wind speed are analyzed by calculating the mean power outputs of turbines located along the outer edges of the farm for different wind directions, wind speeds...

  19. Wind Turbine Converter Control Interaction with Complex Wind Farm Systems

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2013-01-01

    . The same wind turbine converter control strategy is evaluated in two different wind farms. It is emphasised that the grid-side converter controller should be characterised by sufficient harmonic/noise rejection and adjusted depending on wind farms to which it is connected. Various stability indices......This study presents wind turbine converter stability analysis of wind farms in frequency domain. The interaction between the wind turbine control system and the wind farm structure in wind farms is deeply investigated. Two wind farms (i.e. Horns Rev II and Karnice) are taken into consideration...... in this study. It is shown that wind farm components, such as long high-voltage alternating current cables and park transformers, can introduce significant low-frequency series resonances seen from the wind turbine terminals that can affect wind turbine control system operation and overall wind farm stability...

  20. Simulation and optimal control of wind-farm boundary layers

    Science.gov (United States)

    Meyers, Johan; Goit, Jay

    2014-05-01

    In large wind farms, the effect of turbine wakes, and their interaction leads to a reduction in farm efficiency, with power generated by turbines in a farm being lower than that of a lone-standing turbine by up to 50%. In very large wind farms or `deep arrays', this efficiency loss is related to interaction of the wind farms with the planetary boundary layer, leading to lower wind speeds at turbine level. Moreover, for these cases it has been demonstrated both in simulations and wind-tunnel experiments that the wind-farm energy extraction is dominated by the vertical turbulent transport of kinetic energy from higher regions in the boundary layer towards the turbine level. In the current study, we investigate the use of optimal control techniques combined with Large-Eddy Simulations (LES) of wind-farm boundary layer interaction for the increase of total energy extraction in very large `infinite' wind farms. We consider the individual wind turbines as flow actuators, whose energy extraction can be dynamically regulated in time so as to optimally influence the turbulent flow field, maximizing the wind farm power. For the simulation of wind-farm boundary layers we use large-eddy simulations in combination with actuator-disk and actuator-line representations of wind turbines. Simulations are performed in our in-house pseudo-spectral code SP-Wind that combines Fourier-spectral discretization in horizontal directions with a fourth-order finite-volume approach in the vertical direction. For the optimal control study, we consider the dynamic control of turbine-thrust coefficients in an actuator-disk model. They represent the effect of turbine blades that can actively pitch in time, changing the lift- and drag coefficients of the turbine blades. Optimal model-predictive control (or optimal receding horizon control) is used, where the model simply consists of the full LES equations, and the time horizon is approximately 280 seconds. The optimization is performed using a

  1. 8th international workshop on large-scale integration of wind power into power systems as well as on transmission networks for offshore wind farms. Proceedings

    International Nuclear Information System (INIS)

    Betancourt, Uta; Ackermann, Thomas

    2009-01-01

    Within the 8th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Farms at 14th to 15th October, 2009 in Bremen (Federal Republic of Germany), lectures and posters were presented to the following sessions: (1) Keynote session and panel; (2) Grid integration studies and experience: Europe; (3) Connection of offshore wind farms; (4) Wind forecast; (5) High voltage direct current (HVDC); (6) German grid code issues; (7) Offshore grid connection; (8) Grid integration studies and experience: North America; (9) SUPWIND - Decision support tools for large scale integration of wind; (10) Windgrid - Wind on the grid: An integrated approach; (11) IEA Task 25; (12) Grid code issues; (13) Market Issues; (14) Offshore Grid; (15) Modelling; (16) Wind power and storage; (17) Power system balancing; (18) Wind turbine performance; (19) Modelling and offshore transformer.

  2. Potential market of wind farm in China

    Energy Technology Data Exchange (ETDEWEB)

    Pengfei Shi [Hydropower Planning General Inst., Beijing (China)

    1996-12-31

    Wind energy resources are abundant in China, in southeast coast area along with the rapid economic growth, electricity demand has been sharply increased, due to complex terrain detailed assessments are in urgent need. Advanced methodology and computer model should be developed. In this paper the existing wind farms, installed capacity, manufacturers share and projects in the near future are presented. For further development of wind farm in large scale, different ways of local manufacturing wind turbine generators (WTG) are going on. Current policy and barriers are analyzed. 4 refs., 2 figs., 4 tabs.

  3. Grid Integration of Wind Farms

    Science.gov (United States)

    Giæver Tande, John Olav

    2003-07-01

    This article gives an overview of grid integration of wind farms with respect to impact on voltage quality and power system stability. The recommended procedure for assessing the impact of wind turbines on voltage quality in distribution grids is presented. The procedure uses the power quality characteristic data of wind turbines to determine the impact on slow voltage variations, flicker, voltage dips and harmonics. The detailed assessment allows for substantially more wind power in distribution grids compared with previously used rule-of-thumb guidelines. Power system stability is a concern in conjunction with large wind farms or very weak grids. Assessment requires the use of power system simulation tools, and wind farm models for inclusion in such tools are presently being developed. A fixed-speed wind turbine model is described. The model may be considered a good starting point for development of more advanced models, hereunder the concept of variable-speed wind turbines with a doubly fed induction generator is briefly explained. The use of dynamic wind farm models as part of power system simulation tools allows for detailed studies and development of innovative grid integration techniques. It is demonstrated that the use of reactive compensation may relax the short-term voltage stability limit and allow integration of significantly more wind power, and that application of automatic generation control technology may be an efficient means to circumvent thermal transmission capacity constraints. The continuous development of analysis tools and technology for cost-effective and secure grid integration is an important aid to ensure the increasing use of wind energy. A key factor for success, however, is the communication of results and gained experience, and in this regard it is hoped that this article may contribute.

  4. Wind farm design in complex terrain: the FarmOpt methodology

    DEFF Research Database (Denmark)

    Feng, Ju

    Designing wind farms in complex terrain is becoming more and more important, especially for countries like China, where a large portion of the territory is featured as complex terrain. Although potential richer wind resources could be expected at complex terrain sites (thanks to the terrain effec...

  5. Offshore wind farm repowering optimization

    DEFF Research Database (Denmark)

    Hou, Peng; Enevoldsen, Peter; Hu, Weihao

    2017-01-01

    is focused on optimization of offshore wind farm repowering, which is one option for the wind farm owner at end of life for the offshore wind farm. The LCoE is used as the evaluation index to identify whether it is economical to invest in such a way. In an optimized repowering strategy, different types...... of wind turbines are selected to replace the original wind turbines to reconstruct the wind farm, which is demonstrated to be better than the refurbishment approach which replaces the old wind turbines with the same type. The simulations performed in this research reveal that the reconstructed wind farm......, which consists of multiple types of wind turbine, has a smaller LCoE (10.43%) than the refurbishment approach, which shows the superiority of the proposed method. This research contributes an optimization tool to the wind industry, which consequently drives down the cost of energy produced by offshore...

  6. Large eddy simulation of atmospheric boundary layer over wind farms using a prescribed boundary layer approach

    DEFF Research Database (Denmark)

    Chivaee, Hamid Sarlak; Sørensen, Jens Nørkær; Mikkelsen, Robert Flemming

    2012-01-01

    Large eddy simulation (LES) of flow in a wind farm is studied in neutral as well as thermally stratified atmospheric boundary layer (ABL). An approach has been practiced to simulate the flow in a fully developed wind farm boundary layer. The approach is based on the Immersed Boundary Method (IBM......) and involves implementation of an arbitrary prescribed initial boundary layer (See [1]). A prescribed initial boundary layer profile is enforced through the computational domain using body forces to maintain a desired flow field. The body forces are then stored and applied on the domain through the simulation...... and the boundary layer shape will be modified due to the interaction of the turbine wakes and buoyancy contributions. The implemented method is capable of capturing the most important features of wakes of wind farms [1] while having the advantage of resolving the wall layer with a coarser grid than typically...

  7. Wind Farm Grid Integration Using VSC Based HVDC Transmission - An Overview

    DEFF Research Database (Denmark)

    Chaudhary, Sanjay Kumar; Teodorescu, Remus; Rodriguez, Pedro

    2008-01-01

    The paper gives an overview of HVAC and HVDC connection of wind farm to the grid, with an emphasis on Voltage Source Converter (VSC)-based HVDC for large wind farms requiring long distance cable connection. Flexible control capabilities of a VSC-based HVDC system enables smooth integration of wind...... farm into the power grid network while meeting the Grid Code Requirements (GCR). Operation of a wind farm with VSC-based HVDC connection is described....

  8. Wind Farms: Modeling and Control

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam

    2012-01-01

    is minimized. The controller is practically feasible. Yet, the results on load reduction in this approach are not very significant. In the second strategy, the wind farm control problem has been divided into below rated and above rated wind speed conditions. In the above rated wind speed pitch angle and power....... Distributed controller design commences with formulating the problem, where a structured matrix approach has been put in to practice. Afterwards, an H2 control problem is implemented to obtain the controller dynamics for a wind farm such that the structural loads on wind turbines are minimized.......The primary purpose of this work is to develop control algorithms for wind farms to optimize the power production and augment the lifetime of wind turbines in wind farms. In this regard, a dynamical model for wind farms was required to be the basis of the controller design. In the first stage...

  9. Fuzzy generation scheduling for a generation company (GenCo) with large scale wind farms

    International Nuclear Information System (INIS)

    Siahkali, H.; Vakilian, M.

    2010-01-01

    Wind power is a promising alternative in power generation because of its tremendous environmental and social benefits. Generation scheduling (GS) is more important in a power system integrating wind farms. Unlike conventional power generation sources, wind power generators supply intermittent power because of uncertainty in resource. This paper presents a fuzzy approach to the generation scheduling problem of a GenCo considering uncertainties in parameters or constraints such as load, reserve and available wind power generation. The modeling of constraints is an important issue in power system scheduling. A fuzzy optimization approach is an approach that can be used to obtain the generation scheduling under an uncertain environment. In this paper, a fuzzy optimization-based method is developed to solve power system GS problem with fuzzy objective and constraints. The crisp formulation of this GS problem is firstly defined and is rearranged by introduction of a membership function of some constraints and objective function. Then, this fuzzy optimization problem is converted to a crisp optimization and solved using GAMS software by mixed integer nonlinear programming. Employing the fuzzy optimization GS, it is expected that in practice a higher profit would be achieved in the operation and cost management of a real power system with large scale wind farms in different level of constraints' satisfaction. The proposed approach is applied to a sample system (including six conventional units and two wind farms) and the results are compared with the results of crisp solution. This approach is also applied to a larger test case to demonstrate the robustness of this fuzzy optimization method.

  10. Wind farm acceptance for sale? Evidence from the Danish wind farm co-ownership scheme

    DEFF Research Database (Denmark)

    Johansen, K.; Emborg, J.

    2018-01-01

    -investors already support the planned wind farm projects, and many project opponents will not engage themselves in something they are against in principle. Finally, economic benefits potentially gained via OPSS do not appear to compensate for values feared violated by wind farms by many wind farm project...

  11. Grid Integration of Offshore Wind Farms via VSC-HVDC – Dynamic Stability Study

    DEFF Research Database (Denmark)

    Liu, Hongzhi

    farms could seriously impact the operation and stability of their interconnected power system. To assist in maintaining the power system stability when large disturbances occur in the grid, modern offshore wind farms consisting of variable-speed wind turbines are required to provide ancillary services...... such as voltage and frequency control. The greater distance to shore makes commonly used high voltage AC (HVAC) connection unsuitable economically and technically for large offshore wind farms. Alternatively, voltage source converter (VSC)-based high voltage DC (HVDC) transmission becomes more attractive...... and practical to integrate large-scale offshore wind farms into the onshore power grid, owing to its high capacity, advanced controllability and stabilization potential for AC networks etc. In this dissertation, some of the key technical issues with grid integration of large-scale offshore wind farms via VSC...

  12. Optimizing transmission from distant wind farms

    International Nuclear Information System (INIS)

    Pattanariyankool, Sompop; Lave, Lester B.

    2010-01-01

    We explore the optimal size of the transmission line from distant wind farms, modeling the tradeoff between transmission cost and benefit from delivered wind power. We also examine the benefit of connecting a second wind farm, requiring additional transmission, in order to increase output smoothness. Since a wind farm has a low capacity factor, the transmission line would not be heavily loaded, on average; depending on the time profile of generation, for wind farms with capacity factor of 29-34%, profit is maximized for a line that is about 3/4 of the nameplate capacity of the wind farm. Although wind generation is inexpensive at a good site, transmitting wind power over 1600 km (about the distance from Wyoming to Los Angeles) doubles the delivered cost of power. As the price for power rises, the optimal capacity of transmission increases. Connecting wind farms lowers delivered cost when the wind farms are close, despite the high correlation of output over time. Imposing a penalty for failing to deliver minimum contracted supply leads to connecting more distant wind farms.

  13. Stability analysis of offshore wind farm and marine current farm

    Science.gov (United States)

    Shawon, Mohammad Hasanuzzaman

    Renewable energy has been playing an important role to meet power demand and 'Green Energy' market is getting bigger platform all over the world in the last few years. Due to massive increase in the prices of fossil fuels along with global warming issues, energy harvesting from renewable energy sources has received considerable interest, nowadays, where extensive researches are going on to ensure optimum use of renewable sources. In order to meet the increasing demand of electricity and power, integration of renewable energy is getting highest priorities around the world. Wind is one of the most top growing renewable energy resources and wind power market penetration is expected to reach 3.35 percent by 2013 from its present market of about 240 GW. A wind energy system is the most environmental friendly, cost effective and safe among all renewable energy resources available. Another promising form of renewable energy is ocean energy which covers 70 % of the earth. Ocean energy can be tapped from waves, tides and thermal elements. Offshore Wind farm (OWF) has already become very popular for large scale wind power integration with the onshore grid. Recently, marine current farm (MCF) is also showing good potential to become mainstream energy sources and already successfully commissioned in United Kingdom. However, squirrel cage induction generator (SCIG) has the stability problem similar to synchronous generator especially during fault location to restore the electromagnetic torque. Series dynamic braking resistor (SDBR) has been known as a useful mean to stabilize fixed speed wind generator system. On the other hand, doubly fed induction generator (DFIG) has the capability of coupling the control of active and reactive power and to provide necessary reactive power demand during grid fault conditions. Series dynamic braking resistor (SDBR) can also be employed with DFIG to limit the rotor over current. An integration of wind and tidal energy represents a new

  14. Centralised power control of wind farm with doubly fed induction generators

    DEFF Research Database (Denmark)

    Hansen, A.D.; Sørensen, Poul Ejnar; Iov, F.

    2006-01-01

    At the moment, the control ability of wind farms is a prime research concern for the grid integration of large wind farms, due to their required active role in the power system. This paper describes the on-going work of a research project, whose overall objective is to analyse and assess...... the possibilities for control of different wind farm concepts. The scope of this paper is the control of a wind farm made up exclusively of doubly fed induction generators. The paper addresses the design and implementation issues of such a controller and focuses on the ability of the wind farm control strategy...

  15. An aggregate model of grid-connected, large-scale, offshore wind farm for power stability investigations-importance of windmill mechanical system

    DEFF Research Database (Denmark)

    Akhmatov, Vladislav; Knudsen, H.

    2002-01-01

    . Because the shaft system gives a soft coupling between the rotating wind turbine and the induction generator, the large-scale wind farm cannot always be reduced to one-machine equivalent and use of multi-machine equivalents will be necessary for reaching accuracy of the investigation results....... This will be in cases with irregular wind distribution over the wind farm area. The torsion mode of the shaft systems of large wind turbines is commonly in the range of 1-2 Hz and close to typical values of the electric power grid eigenfrequencies why there is a risk of oscillation between the wind turbines...... and the entire network. All these phenomena are different compared to previous experiences with modelling of conventional power plants with synchronous generators and stiff shaft systems....

  16. Wind speed dynamical model in a wind farm

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2010-01-01

    , the dynamic model for wind flow will be established. The state space variables are determined based on a fine mesh defined for the farm. The end goal of this method is to assist the development of a dynamical model of a wind farm that can be engaged for better wind farm control strategies....

  17. Spatiotemporal distribution of nitrogen dioxide within and around a large-scale wind farm – a numerical case study

    Directory of Open Access Journals (Sweden)

    J. Mo

    2017-12-01

    Full Text Available As a renewable and clean energy source, wind power has become the most rapidly growing energy resource worldwide in the past decades. Wind power has been thought not to exert any negative impacts on the environment. However, since a wind farm can alter the local meteorological conditions and increase the surface roughness lengths, it may affect air pollutants passing through and over the wind farm after released from their sources and delivered to the wind farm. In the present study, we simulated the nitrogen dioxide (NO2 air concentration within and around the world's largest wind farm (Jiuquan wind farm in Gansu Province, China using a coupled meteorology and atmospheric chemistry model WRF-Chem. The results revealed an edge effect, which featured higher NO2 levels at the immediate upwind and border region of the wind farm and lower NO2 concentration within the wind farm and the immediate downwind transition area of the wind farm. A surface roughness length scheme and a wind turbine drag force scheme were employed to parameterize the wind farm in this model investigation. Modeling results show that both parameterization schemes yield higher concentration in the immediate upstream of the wind farm and lower concentration within the wind farm compared to the case without the wind farm. We infer this edge effect and the spatial distribution of air pollutants to be the result of the internal boundary layer induced by the changes in wind speed and turbulence intensity driven by the rotation of the wind turbine rotor blades and the enhancement of surface roughness length over the wind farm. The step change in the roughness length from the smooth to rough surfaces (overshooting in the upstream of the wind farm decelerates the atmospheric transport of air pollutants, leading to their accumulation. The rough to the smooth surface (undershooting in the downstream of the wind farm accelerates the atmospheric transport of air pollutants, resulting in

  18. Dependence of optimal wind turbine spacing on wind farm length

    NARCIS (Netherlands)

    Stevens, Richard Johannes Antonius Maria

    2016-01-01

    Recent large eddy simulations have led to improved parameterizations of the effective roughness height of wind farms. This effective roughness height can be used to predict the wind velocity at hub-height as function of the geometric mean of the spanwise and streamwise turbine spacings and the

  19. CleverFarm - A superSCADA system for wind farms

    DEFF Research Database (Denmark)

    Juhl, A.; Hansen, K.G.; Giebhardt, J.

    2004-01-01

    The CleverFarm project started out to build an integrated monitoring system for wind farms, where all information would be available and could be used across the wind farm for maintenance and component health assessments. This would enable wind farmoperators to prioritise their efforts, since the...

  20. Harmonic models of a back-to-back converter in large offshore wind farms compared with measurement data

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2009-01-01

    The offshore wind farm with installed back-to-back power converter in wind turbines is studied. As an example the Burbo Bank offshore wind farm with Siemens Wind Power wind turbines is taken into consideration. The wind farm is simulated in DIgSILENT Power Factory software in order to determine...

  1. Grid support of a wind farm with active stall wind turbines and AC grid connection

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul Ejnar; Iov, F.

    2006-01-01

    grid connection. The designed control system has the task of enabling such a wind farm to provide the best grid support. It is based on two control levels: a supervisory control level, which controls the power production of the whole farm by sending out reference signals to each individual wind turbine......One of the main concerns in the grid integration of large wind farms is their ability to behave as active controllable components in the power system. This article presents the design of a new integrated power control system for a wind farm made up exclusively of active stall wind turbines with AC......, and a local control level, which ensures that the reference power signals at the wind turbine level are reached. The ability of active stall wind farms with AC grid connection to control the power production to the reference power ordered by the operators is assessed and discussed by means of simulations....

  2. Wind Farm Wake: The Horns Rev Photo Case

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Rasmussen, Leif; Peña, Alfredo

    2013-01-01

    The aim of the paper is to examine the nowadays well-known wind farm wake photographs taken on 12 February 2008 at the offshore Horns Rev 1 wind farm. The meteorological conditions are described from observations from several satellite sensors quantifying clouds, surface wind vectors and sea surf...... in the wake regions with relatively high axial velocities and high turbulent kinetic energy. The wind speed is near cut-in and most turbines produce very little power. The rotational pattern of spiraling bands produces the large-scale structure of the wake fog....

  3. A Hybrid Wind-Farm Parametrization for Mesoscale and Climate Models

    Science.gov (United States)

    Pan, Yang; Archer, Cristina L.

    2018-04-01

    To better understand the potential impact of wind farms on weather and climate at the regional to global scales, a new hybrid wind-farm parametrization is proposed for mesoscale and climate models. The proposed parametrization is a hybrid model because it is not based on physical processes or conservation laws, but on the multiple linear regression of the results of large-eddy simulations (LES) with the geometric properties of the wind-farm layout (e.g., the blockage ratio and blockage distance). The innovative aspect is that each wind turbine is treated individually based on its position in the farm and on the wind direction by predicting the velocity upstream of each turbine. The turbine-induced forces and added turbulence kinetic energy (TKE) are first derived analytically and then implemented in the Weather Research and Forecasting model. Idealized simulations of the offshore Lillgrund wind farm are conducted. The wind-speed deficit and TKE predicted with the hybrid model are in excellent agreement with those from the LES results, while the wind-power production estimated with the hybrid model is within 10% of that observed. Three additional wind farms with larger inter-turbine spacing than at Lillgrund are also considered, and a similar agreement with LES results is found, proving that the hybrid parametrization works well with any wind farm regardless of the spacing between turbines. These results indicate the wind-turbine position, wind direction, and added TKE are essential in accounting for the wind-farm effects on the surroundings, for which the hybrid wind-farm parametrization is a promising tool.

  4. Wind farm efficiency assessed by WRF with a statistical-dynamical approach

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    2016-01-01

    the power production of a target wind farm and (II) how large wind farms can get if they are to remain efficient and productive power generators. The modelling of wind farm wake flows is challenging, since it includes processes from the micro- to mesoscale meteorology. We use the Weather Research......A pledge to increase the share of renewable energies has led to a focus on offshore wind energy in many western European countries. With an increasing number of offshore wind farms to be installed it becomes important to understand (I) the degree to which wakes from neighbouring wind farms affect...... and Forecast (WRF) model that allows us to simulate mesoscale features of wind farm wakes. Its limited horizontal resolution – in microscale terms – however, requires flow characteristics, such as single turbine wakes, to be parametrised....

  5. Dynamical and statistical-dynamical modelling of wind farm flows with WRF

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    2016-01-01

    the power production of a target wind farm and (II) how large wind farms can get if they are to remain efficient and productive power generators. The modelling of wind farm wake flows is challenging, since it includes processes from the micro- to mesoscale meteorology. We use the Weather Research......A pledge to increase the share of renewable energies has led to a focus on offshore wind energy in many western European countries. With an increasing number of offshore wind farms to be installed it becomes important to understand (I) the degree to which wakes from neighbouring wind farms affect...... and Forecast (WRF) model that allows us to simulate mesoscale features of wind farm wakes. Its limited horizontal resolution – in microscale terms – however, requires flow characteristics, such as single turbine wakes, to be parametrised....

  6. A Wind Farm Electrical Systems Evaluation with EeFarm-II

    Directory of Open Access Journals (Sweden)

    Jan Pierik

    2010-03-01

    Full Text Available EeFarm-II is used to evaluate 13 different electrical systems for a 200 MW wind farm with a 100 km connection to shore. The evaluation is based on component manufacturer data of 2009. AC systems are compared to systems with DC connections inside the wind farm and DC connection to shore. Two options have the best performance for this wind farm size and distance: the AC system and the system with a DC connection to shore. EeFarm-II is a user friendly computer program for wind farm electrical and economic evaluation. It has been built as a Simulink Library in the graphical interface of Matlab-Simulink. EeFarm-II contains models of wind turbines, generators, transformers, AC cables, inductors, nodes, splitters, PWM converters, thyristor converters, DC cables, choppers and statcoms.

  7. Collection System Cable Routing and Wake Losses Optimization in Offshore Wind Farms

    NARCIS (Netherlands)

    Fragoso Rodrigues, S.M.; Bauer, P.; Bosman, P.A.N.; Pierik, J.

    2014-01-01

    Offshore wind farms with high installed capacities and located further from the shore are starting to be built by northern European countries. Furthermore, it is expected that by 2020, several dozens of large offshore wind farms will be built in the Baltic, Irish and North seas. These wind farms

  8. Lightning hazard reduction at wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Kithil, R. [National Lightning Safety Institute, Louisville, CO (United States)

    1997-12-31

    The USA wind farm industry (WFI) largely is centered in low-lightning areas of the State of California. While some evidence of lightning incidents is reported here, the problem is not regarded as serious by most participants. The USA WFI now is moving eastward, into higher areas of lightning activity. The European WFI has had many years experience with lightning problems. One 1995 German study estimated that 80% of wind turbine insurance claims paid for damage compensation were caused by lightning strikes. The European and USA WFI have not adopted site criteria, design fundamentals, or certification techniques aimed at lightning safety. Sufficient evidence about lightning at wind farms is available to confirm that serious potential problems exist.

  9. Combining offshore wind energy and large-scale mussel farming: background & technical, ecological and economic considerations

    NARCIS (Netherlands)

    Lagerveld, S.; Rockmann, C.; Scholl, M.M.; Bartelings, H.; Burg, van den S.W.K.; Jak, R.G.; Jansen, H.M.; Klijnstra, J.; Leopold, M.F.; Poelman, M.; Smith, S.R.; Stavenuiter, J.; Veenstra, F.A.; Veltman, C.; Westra, C.

    2014-01-01

    This Blauwdruk project report presents background and technical, ecological and economic considerations of the potential combination of offshore wind energy production and large-scale mussel farming in offshore areas in the North Sea. The main objective of the Blauwdruk project was to study the

  10. Havsnaes wind farm - The project financing of a Swedish wind farm

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    In March 2008 the ground breaking project financing of the 95 MW Havsnaes wind farm was completed. Havsnaes represents one of the cornerstones in portfolio of Venus Vind, controlled by HgCapital, where sustainable Scandinavian strength is build through industrial scale wind farms with local presence. At the time, Havsnaes represented the largest energy project financing in the market, it is also the first true project financing of a major Swedish wind farm. The aim of this study is to highlight the process of project financing and additional lessons learnt from the Havsnaes transaction. Investment in renewable energy projects often includes international investors. We welcome the growing Swedish wind market, banks and other financial institutions, politicians and other relevant decision makers to take part of our findings. Sponsorship provided by the Swedish Energy Agency has enabled the completion of this study.

  11. Topologies of multiterminal HVDC-VSC transmission for large offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Gomis-Bellmunt, Oriol [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2. 08028 Barcelona (Spain); IREC Catalonia Institute for Energy Research, Barcelona (Spain); Liang, Jun; Ekanayake, Janaka; King, Rosemary; Jenkins, Nicholas [School of Engineering, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA, Wales (United Kingdom)

    2011-02-15

    Topologies of multiterminal HVDC-VSC transmission systems for large offshore wind farms are investigated. System requirements for multiterminal HVDC are described, particularly the maximum power loss allowed in the event of a fault. Alternative control schemes and HVDC circuit topologies are reviewed, including the need for HVDC circuit breakers. Various topologies are analyzed and compared according to a number of criteria: number and capacity of HVDC circuits, number of HVDC circuit breakers, maximum power loss, flexibility, redundancy, lines utilization, need for offshore switching platforms and fast communications. (author)

  12. Power flow control and damping enhancement of a large wind farm using a superconducting magnetic energy storage unit

    DEFF Research Database (Denmark)

    Chen, S. S.; Wang, L.; Lee, W. J.

    2009-01-01

    A novel scheme using a superconducting magnetic energy storage (SMES) unit to perform both power flow control and damping enhancement of a large wind farm (WF) feeding to a utility grid is presented. The studied WF consisting of forty 2 MW wind induction generators (IGs) is simulated...

  13. Wind Farm Wake Models From Full Scale Data

    DEFF Research Database (Denmark)

    Knudsen, Torben; Bak, Thomas

    2012-01-01

    This investigation is part of the EU FP7 project “Distributed Control of Large-Scale Offshore Wind Farms”. The overall goal in this project is to develop wind farm controllers giving power set points to individual turbines in the farm in order to minimise mechanical loads and optimise power. One...... on real full scale data. The modelling is based on so called effective wind speed. It is shown that there is a wake for a wind direction range of up to 20 degrees. Further, when accounting for the wind direction it is shown that the two model structures considered can both fit the experimental data...

  14. An assessment of the environmental effects of offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This report focuses on the development of an approach to the formal environmental assessment of large-scale offshore wind farms around the UK coast which will be required by EU Directives. The legislative background and policy framework are outlined, and key issues to be addressed in the environmental assessment are highlighted. Available information on the manufacture and transportation of wind farm equipment, turbine and cable installation, operation of an offshore wind farm, and wind farm decommissioning is reviewed and recommendations are given. The role of offshore wind power in meeting the UK's commitment to reducing emissions of carbon dioxide and other greenhouse gases and its targets for generating 10% of the UK's electricity from renewable energy sources is discussed.

  15. The effect of a large Danish offshore wind farm on harbor and grey seal haul-out behaviour

    DEFF Research Database (Denmark)

    Edrén, Susi Manuela Clermont; Andersen, Signe May; Teilmann, Jonas

    2010-01-01

    This study investigates the effects of the construction and operation of a large Danish offshore wind farm on harbor and gray seal haul-out behavior within a nearby (4 km) seal sanctuary. Time-lapse photography, visual monitoring, and aerial surveys were used to monitor the number of seals on land...... in daylight hours. Seals were monitored during two preconstruction periods (19 June–31 August 2001 and April–August 2002), a construction period of the wind farm (August 2002–December 2003), and a period of operation of the wind farm (December 2003–December 2004). Monthly aerial surveys were conducted...... to estimate the proportion of seals in the sanctuary relative to neighboring haul-out sites. From preconstruction to construction and through the first year of operation the number of harbor seals in the sanctuary increased at the same rate as the number of seals at the neighboring haul-out sites. No long...

  16. Wind farm design optimization

    Energy Technology Data Exchange (ETDEWEB)

    Carreau, Michel; Morgenroth, Michael; Belashov, Oleg; Mdimagh, Asma; Hertz, Alain; Marcotte, Odile

    2010-09-15

    Innovative numerical computer tools have been developed to streamline the estimation, the design process and to optimize the Wind Farm Design with respect to the overall return on investment. The optimization engine can find the collector system layout automatically which provide a powerful tool to quickly study various alternative taking into account more precisely various constraints or factors that previously would have been too costly to analyze in details with precision. Our Wind Farm Tools have evolved through numerous projects and created value for our clients yielding Wind Farm projects with projected higher returns.

  17. Maximum Energy Yield Oriented Turbine Control in PMSG based Wind Farm

    DEFF Research Database (Denmark)

    Tian, Jie; Zhou, Dao; Su, Chi

    2017-01-01

    : In the modern power systems, with the fast integration of the wind power into the grid, it turns to develop large-scale offshore wind farms equipped with the permanent magnet synchronous generator (PMSG) wind turbine. In large-scale offshore wind farms, the wind turbine operating reliability...... and the wake effect in the wind farm became important issues. The pitch angle and tip speed ratio are the two degrees of freedom for the PMSG wind turbine active power control, which are also the determining factors of the wind turbine lifetime. As the energy production of the wind turbine is the product...... of its active power and lifetime, the energy production can be maximised by optimising its pitch angle and tip speed ratio. In this study, the energy production of a 2 MW PMSG wind turbine is maximised by optimising its pitch angle and tip speed ratio. Moreover, taking into account the wake effect...

  18. Simulation of power fluctuation of wind farms based on frequency domain

    DEFF Research Database (Denmark)

    Lin, Jin; Sun, Yuanzhang; Li, Guojie

    2011-01-01

    , however, is incapable of completely explaining the physical mechanism of randomness of power fluctuation. To remedy such a situation, fluctuation modeling based on the frequency domain is proposed. The frequency domain characteristics of stochastic fluctuation on large wind farms are studied using...... the power spectral density of wind speed, the frequency domain model of a wind power generator and the information on weather and geography of the wind farms. The correctness and effectiveness of the model are verified by comparing the measurement data with simulation results of a certain wind farm. © 2011...

  19. Offshore Wind Farm Layout Design Considering Optimized Power Dispatch Strategy

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; N. Soltani, Mohsen

    2017-01-01

    Offshore wind farm has drawn more and more attention recently due to its higher energy capacity and more freedom to occupy area. However, the investment is higher. In order to make a cost-effective wind farm, the wind farm layout should be optimized. The wake effect is one of the dominant factors...... leading to energy losses. It is expected that the optimized placement of wind turbines (WT) over a large sea area can lead to the best tradeoff between energy yields and capital investment. This paper proposes a novel way to position offshore WTs for a regular shaped wind farm. In addition to optimizing...... the direction of wind farm placement and the spacing between WTs, the control strategy’s impact on energy yields is also discussed. Since the problem is non-convex and lots of optimization variables are involved, an evolutionary algorithm, the particle swarm optimization algorithm (PSO), is adopted to find...

  20. Power reserve provision with wind farms. Grid integration of wind power

    Energy Technology Data Exchange (ETDEWEB)

    Gesino, Alejandro J.

    2011-07-01

    Wind power is, admittedly, different from other power technologies and integrating large amounts of it in the existing power systems is a challenge that requires innovative approaches to keep the sustainability of the power system operation. In the coming years its contribution to the system security will become mandatory as far as the trend goes towards more decentralized structures and an increase in complexity due to a higher number of market participants. This PhD addresses one of the fundamental ancillary services researching about a secure and flexible methodology for power reserve provision with wind farms. Based on the current needs and security standards of those highly developed European grid codes, a new model for power reserve provision with wind power is developed. This methodology, algorithms and variables are tested based on real scenarios from five German wind farm clusters. Finally, once the methodology for power reserve provision with wind power has been tested, real control capabilities from already installed wind farms in Germany and Portugal are analyzed. Their capabilities of following control commands as well as an error deviation analysis are also presented. (orig.)

  1. Coordinated control strategy for hybrid wind farms with DFIG-based and PMSG-based wind farms during network unbalance

    DEFF Research Database (Denmark)

    Yao, Jun; Liu, Ruikuo; Zhou, Te

    2017-01-01

    This paper investigates the coordinated control strategy for a hybrid wind farm with doubly fed induction generator (DFIG)-based and direct-driven permanent-magnet synchronous generator (PMSG)-based wind farms during network unbalance. The negative-sequence current output capabilities of DFIG...... to the controllable operating regions, a targets selection scheme for each control unit is proposed to improve the stability of the hybrid wind farms containing both DFIG-based and PMSG-based wind farms during network unbalance, especially to avoid DFIG-based wind farm tripping from connected power grid under severe...... grid voltage unbalance conditions. Finally, the proposed coordinated control strategy is validated by the simulation results of a 30-MW-DFIG-based wind farm and a 30-MW-PMSG-based wind farm under different operation conditions and experimental results on a laboratory-scale experimental rig under severe...

  2. A survey of modelling methods for high-fidelity wind farm simulations using large eddy simulation

    DEFF Research Database (Denmark)

    Breton, Simon-Philippe; Sumner, J.; Sørensen, Jens Nørkær

    2017-01-01

    surveys the most common schemes available to model the rotor, atmospheric conditions and terrain effects within current state-of-the-art LES codes, of which an overview is provided. A summary of the experimental research data available for validation of LES codes within the context of single and multiple......Large eddy simulations (LES) of wind farms have the capability to provide valuable and detailed information about the dynamics of wind turbine wakes. For this reason, their use within the wind energy research community is on the rise, spurring the development of new models and methods. This review...

  3. Havsnaes Wind Farm. A guide on Health and Safety

    Energy Technology Data Exchange (ETDEWEB)

    Wettin, Martina [Goovinn, Goeteborg (Sweden); Jiven, Anna [Nordisk Vindkraft, Goeteborg (Sweden)

    2011-07-01

    This guide has been developed by Nordisk Vindkraft in co-operation with Energimyndigheten (the Swedish Energy Agency). The main purpose is to raise the attention to work environment matters when developing, constructing and operating large-scale wind farms in the northern parts of Sweden. The Swedish wind industry is relatively young. Work Environment Management and legal awareness has been identified by the Swedish Government as one crucial factor for ensuring sound and rapid development of the industry. Havsnaes is to date the largest onshore wind farm in Sweden. Whilst developing this project, Nordisk Vindkraft has gained extensive experience and developed a profound understanding of the prerequisites for the Swedish large-scale wind industry. The wind farm's size, complexity and geographical location near Stroemsund in Jaemtland qualify the project as an excellent pilot study. Preventing accidents and ill-health largely depends on your knowledge, competence and the resources you are able and willing to spend. The key for success is a pro-active approach. During the Havsnaes project, Nordisk Vindkraft has spent considerable amount of time and effort on the management of Work Environment. We hope our gained experience will be beneficial for our industry as a whole.

  4. Cooperative wind turbine control for maximizing wind farm power using sequential convex programming

    International Nuclear Information System (INIS)

    Park, Jinkyoo; Law, Kincho H.

    2015-01-01

    Highlights: • The continuous wake model describes well the wake profile behind a wind turbine. • The wind farm power function describes well the power production of a wind farm. • Cooperative control increases the wind farm power efficiency by 7.3% in average. • SCP can be employed to efficiently optimize the control actions of wind turbines. - Abstract: This paper describes the use of a cooperative wind farm control approach to improve the power production of a wind farm. The power production by a downstream wind turbine can decrease significantly due to reduced wind speed caused by the upstream wind turbines, thereby lowering the overall wind farm power production efficiency. In spite of the interactions among the wind turbines, the conventional (greedy) wind turbine control strategy tries to maximize the power of each individual wind turbine by controlling its yaw angle, its blade pitch angle and its generator torque. To maximize the overall wind farm power production while taking the wake interference into account, this study employs a cooperative control strategy. We first derive the wind farm power as a differentiable function of the control actions for the wind turbines in a wind farm. The wind farm power function is then maximized using sequential convex programming (SCP) to determine the optimum coordinated control actions for the wind turbines. Using an example wind farm site and available wind data, we show how the cooperative control strategy improves the power production of the wind farm

  5. Design optimization of offshore wind farms with multiple types of wind turbines

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2017-01-01

    Most studies on offshore wind farm design assume a uniform wind farm, which consists of an identical type of wind turbines. In order to further reduce the cost of energy, we investigate the design of non-uniform offshore wind farms, i.e., wind farms with multiple types of wind turbines and hub-he...

  6. Scope and prospects of re-engineering and retrofitting wind farms in India

    International Nuclear Information System (INIS)

    Rajsekhar, B.; Van Hulle, F.J.L.

    2001-09-01

    The paper starts with a brief analysis of the characteristics of the Indian wind energy programmes while enumerating the developments that have taken place so far. In view of the large scope for renewable energy based power generation and in order to boost the present uprise of the wind farm development, the authors investigate the possibilities that lay in re-engineering of existing wind farms. Existing wind farm entrepreneurs are showing interest to improve the performance of their wind farms. New initiatives are suggested addressing the involved technical and commercial concerns of both the state-run utility (the principal customer of wind generated electricity) and wind farm entrepreneur to spur development of economically competitive wind-power plants In addition, inferences are drawn from a recently conducted detailed case study at a 5 year old large wind farm in Muppandal area. The study involved conducting detailed WAsP based analysis based on remote land use and land cover details interfacing with GIS. In addition, detailed site investigations were conducted to assess the health of the machines and the adequacy of the power evacuation facility together with the analysis of the machine down times. The paper highlights the benefits that can be expected from such undertakings for several parties both in India and in EU. The paper finally outlines the possible business opportunities and economic benefits that exist for retrofitting and re-engineering in the country, which has over 700 individually designed wind farms. 2 refs

  7. Multi-objective Optimization of Large Wind Farm Parameters for Harmonic Instability and Resonance Conditions

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2016-01-01

    wind farms in order to reduce the resonance probability and guarantee harmonic stability. In fact, a general multiobjective optimization procedure based on the genetic algorithm is proposed to set the poles of the wind farm in a desired location in order to minimize the number of the resonance...

  8. Intelligent control on wind farm

    DEFF Research Database (Denmark)

    Wei, Mu; Chen, Zhe

    2010-01-01

    with the wind farm makes the grid more vulnerable. The communication technologies have been considered as a solution to solve the problems according to the IEC 61400-25 series protocols. This paper presents the significance of communication technologies in wind farm system by the simulations on some practical......Since the renewable energy is popularly applied in power industry, especially the smart grid is fast developing all over the world during these years, the reliable connection between a wind farm and the main grid has been focused on. Due to the difficult control on the wind energy, the connection...... scenarios. By delivering the signals among WTs (wind turbines) and control centers, they both are able to recognize another side’s operation situation and to adjust its own state to realize the optimization. A scenario is designed in this paper, in which a fault occurs in wind farm; then the protection...

  9. The potential of wind farms

    International Nuclear Information System (INIS)

    Hauge Madsen, P.; Lundsager, P.

    1992-09-01

    Papers presented at the European wind energy conference on the potential of wind farms are presented. The aim of the conference was to bring into focus the problems, experiences and potential of the application of wind power in wind power farms as a contribution to the European and global energy supply. It was considered that the interchange of experience among representatives of science, utilities, industry, environment and energy planning, together with those who represent financial and insurance interests, would create a better understanding of all aspects of wind power for its future successful development. The subjects covered concern surveys of national planning and policies regarding wind energy utilization and national and global development of wind turbine arrays. The performance of some individual wind farms is described. Papers also deal with utility and project planning, wind prediction and certification, wind loads and fatigus, wakes, noise and control. (AB)

  10. The potential of wind farms

    International Nuclear Information System (INIS)

    Hauge Madsen, P.; Lundsager, P.

    1992-09-01

    Papers presented at the European wind energy conference on the potential of wind farms are presented. The aim of the conference was to bring into focus the problems, experiences and potential of the application of wind power in wind power farms as a contribution to the European and global energy supply. It was considered that the interchange of experience among representatives of science, utilities, industry, environment and energy planning, together with those who represent financial and insurance interests, would create a better understanding of all aspects of wind power for its future successful development. The subjects covered concern surveys of national planning and policies regarding wind energy utilization and national and global development of wind turbine arrays. The performance of some individual wind farms is described. Papers also deal with utility and project planning, wind prediction and certification, wind loads and fatigues, wakes, noise and control. (AB)

  11. Wind Farm Wake

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Karagali, Ioanna; Volker, Patrick

    2017-01-01

    On 25 January 2016 at 12:45 UTC several photographs of the offshore wind farm Horns Rev 2 were taken by helicopter pilot Gitte Lundorff with an iPhone. A very shallow layer of fog covered the sea. The photos of the fog over the sea dramatically pictured the offshore wind farm wake. Researchers got...... together to investigate the atmospheric conditions at the time of the photos by analysing local meteorological observations and wind turbine information, satellite remote sensing and nearby radiosonde data. Two wake models and one mesoscale model were used to model the case and explain what was seen....

  12. Large eddy simulation study of the kinetic energy entrainment by energetic turbulent flow structures in large wind farms

    Science.gov (United States)

    VerHulst, Claire; Meneveau, Charles

    2014-02-01

    In this study, we address the question of how kinetic energy is entrained into large wind turbine arrays and, in particular, how large-scale flow structures contribute to such entrainment. Previous research has shown this entrainment to be an important limiting factor in the performance of very large arrays where the flow becomes fully developed and there is a balance between the forcing of the atmospheric boundary layer and the resistance of the wind turbines. Given the high Reynolds numbers and domain sizes on the order of kilometers, we rely on wall-modeled large eddy simulation (LES) to simulate turbulent flow within the wind farm. Three-dimensional proper orthogonal decomposition (POD) analysis is then used to identify the most energetic flow structures present in the LES data. We quantify the contribution of each POD mode to the kinetic energy entrainment and its dependence on the layout of the wind turbine array. The primary large-scale structures are found to be streamwise, counter-rotating vortices located above the height of the wind turbines. While the flow is periodic, the geometry is not invariant to all horizontal translations due to the presence of the wind turbines and thus POD modes need not be Fourier modes. Differences of the obtained modes with Fourier modes are documented. Some of the modes are responsible for a large fraction of the kinetic energy flux to the wind turbine region. Surprisingly, more flow structures (POD modes) are needed to capture at least 40% of the turbulent kinetic energy, for which the POD analysis is optimal, than are needed to capture at least 40% of the kinetic energy flux to the turbines. For comparison, we consider the cases of aligned and staggered wind turbine arrays in a neutral atmospheric boundary layer as well as a reference case without wind turbines. While the general characteristics of the flow structures are robust, the net kinetic energy entrainment to the turbines depends on the presence and relative

  13. Wind resource modelling for micro-siting - Validation at a 60-MW wind farm site

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, J C; Gylling Mortensen, N [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark); Said, U S [New and Renewable Energy Authority, Cairo (Egypt)

    1999-03-01

    This paper investigates and validates the applicability of the WAsP-model for layout optimization and micro-siting of wind turbines at a given site for a 60-MW wind farm at Zafarana at the Gulf of Suez in Egypt. Previous investigations show large gradients in the wind climate within the area. For the design and optimization of the wind farm it was found necessary to verify the WAsP extrapolation of wind atlas results from 2 existing meteorological masts located 5 and 10 km, respectively, from the wind farm site. On-site measurements at the 3.5 x 3.5 km{sup 2} wind farm site in combination with 7 years of near-site wind atlas measurements offer significant amounts of data for verification of wind conditions for micro-siting. Wind speeds, wind directions, turbulence intensities and guests in 47.5 m a.g.l. have been measured at 9 locations across the site. Additionally, one of the site masts is equipped as a reference mast, measuring both vertical profiles of wind speed and temperature as well as air pressure and temperature. The exercise is further facilitated by the fact that winds are highly uni-directional; the north direction accounting for 80-90% of the wind resource. The paper presents comparisons of 5 months of on-site measurements and modeled predictions from 2 existing meteorological masts located at distances of 5 and 10 km, respectively, from the wind farm site. Predictions based on terrain descriptions of the Wind Atlas for the Gulf of Suez 1991-95 showed over-predictions of wind speeds of 4-10%. With calibrated terrain descriptions, made based on measured data and a re-visit to critical parts of the terrain, the average prediction error of wind speeds was reduced to about 1%. These deviations are smaller than generally expected for such wind resource modeling, clearly documenting the validity of using WAsP modeling for micro-siting and layout optimization of the wind farm. (au)

  14. To conserve, or not to conserve ... : Large eddy simulation of wind farms with energy-conserving schemes

    NARCIS (Netherlands)

    Mehta, D.

    2016-01-01

    This thesis concerns the industrial application of large eddy simulation to wind farm aerodynamics. Through a series of simple tests, it presents the pros and cons of using energy-conserving time integration and furthers the importance of a dissipation-free spatial discretisation. Finally, it

  15. Distributed Model Predictive Control for Active Power Control of Wind Farm

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Rasmussen, Claus Nygaard

    2014-01-01

    This paper presents the active power control of a wind farm using the Distributed Model Predictive Controller (D- MPC) via dual decomposition. Different from the conventional centralized wind farm control, multiple objectives such as power reference tracking performance and wind turbine load can...... be considered to achieve a trade-off between them. Additionally, D- MPC is based on communication among the subsystems. Through the interaction among the neighboring subsystems, the global optimization could be achieved, which significantly reduces the computation burden. It is suitable for the modern large......-scale wind farm control....

  16. Calculating carbon budgets of wind farms on Scottish peatlands

    Directory of Open Access Journals (Sweden)

    D.R. Nayak

    2010-04-01

    Full Text Available The reliability of calculation methods for the carbon emission savings to be achieved in Scotland by replacing power generated from fossil fuels (and other more conventional sources with that produced by large-scale wind farm developments is a cause for concern, largely in relation to wind farms sited on peatlands. Scottish Government policy is to deliver renewable energy without environmental harm, and to meet biodiversity objectives including the conservation of designated wildlife sites and important habitats such as peatlands. The implications for carbon emissions of developing a wind farm are, therefore, just one aspect of the suite of considerations that the planning system takes into account. This paper presents a simple methodology for prospectively calculating the potential carbon emission savings to be realised by developing wind farms on peatland, forestland or afforested peatland. The total carbon emission savings of an individual wind farm are estimated by accounting emissions from the power source that will be replaced by wind power against: loss of carbon due to production, transportation, erection, operation and dismantling of the wind farm components (the infrastructure overhead; loss of carbon due to backup power generation; loss of carbon stored in peat and forest; loss of carbon-fixing potential of peatland and forest; and carbon savings due to habitat improvement. Most of the carbon losses are determined by national infrastructure, but those from peat soil and plants are influenced by site selection and management practices. The extent of drainage around each constructed element of the wind farm is a major factor for greenhouse gas emissions. Consideration of an example site with a low extent of drainage, where management practices that minimise net carbon losses (e.g. undrained floating roads, habitat improvement and site restoration on decommissioning were used indicates that emissions from the soil and plants may cancel

  17. Attitude and acceptance of offshore wind farms

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Möller, B.

    2011-01-01

    farms attributes on attitude towards offshore wind farms. The results point towards that the travel time and the attributes of the nearest offshore wind farm influence the attitude significantly. Travel time has mixed effects on the attitude, whilst offshore wind farms with many turbines generate more...... a novel contribution to this field. First of all, we give a thorough review of the studies that have analysed the relation between experience with wind turbines and attitude. In addition, we supplement the review by analysing the effect of travel distance to the nearest offshore wind farm and the wind...

  18. Hydroacoustic registration of fish abundance of offshore wind farms. Horns Rev offshore wind farm. Annual report 2004.

    Energy Technology Data Exchange (ETDEWEB)

    Hvidt, C.B.; Bruenner, L.; Reier Knudsen, F.

    2005-05-15

    Elsam Engineering AS has approved the implementation of a project concerning the registration of fish communities in Horns Rev Offshore Wind Farm with use of hydroacoustic methods. In a joint effort, Bio/consult as, Carl Bro as and SIMRAD AS have monitored the fish communities at Horns Rev Offshore Wind Farm using a new hydroacoustic methodology. The new hydroacoustic technique combines the use of scientific sonar acoustics with GPS to determine the density, diversity and location of fish. The objectives of this project were to test the possibility of using hydroacoustic techniques as alternative methods to traditional techniques to assess the fish assemblage inhabiting offshore wind farms and to investigate the possible effect from the wind farm and hard bottom substrates (turbine foundations) on fish abundance. The field study was carried out October 9-10, 2004 and consisted of four horizontal hydroacoustic survey transects each covering impact and reference areas. Transects were surveyed in order to achieve identical impact and reference transect pairs concerning environment, topography and time correspondence. The hydroacoustic equipment consisted of a SIMRAD EK60/EY60 echo sounder with a split-beam transducer (Simrad ES 120-4x10) mounted on a pan and tilt unit, a transceiver, a laptop extended with a GPS-receiver and additional large external hard discs. The raw data files from EK60 were converted to echogram files suitable for the post processing application, Sonar5-Pro. The Sonar5-Pro software makes it possible to filter out echo detections from the surface and the bottom, as well as perform cross filter detection. The validity of the results using the hydroacoustic method is high due to the cross filtering and single target tracking technique. From the hydroacoustic results, no or very little effect from the wind farm or from hard bottom substrates was found on the fish densities at Horns Rev Wind Farm at the time of the survey. The execution of the field

  19. Challenges and options for large scale integration of wind power

    International Nuclear Information System (INIS)

    Tande, John Olav Giaever

    2006-01-01

    Challenges and options for large scale integration of wind power are examined. Immediate challenges are related to weak grids. Assessment of system stability requires numerical simulation. Models are being developed - validation is essential. Coordination of wind and hydro generation is a key for allowing more wind power capacity in areas with limited transmission corridors. For the case study grid depending on technology and control the allowed wind farm size is increased from 50 to 200 MW. The real life example from 8 January 2005 demonstrates that existing marked based mechanisms can handle large amounts of wind power. In wind integration studies it is essential to take account of the controllability of modern wind farms, the power system flexibility and the smoothing effect of geographically dispersed wind farms. Modern wind farms contribute to system adequacy - combining wind and hydro constitutes a win-win system (ml)

  20. Detecting, categorizing and forecasting large romps in wind farm power output using meteorological observations and WPPT

    DEFF Research Database (Denmark)

    Cutler, N.; Kay, M.; Jacka, K.

    2007-01-01

    The Wind Power Prediction Tool (WPPT) has been installed in Australia for the first time, to forecast the power output from the 65MW Roaring 40s Renewable Energy P/L Woolnorth Bluff Point wind form. This article analyses the general performance of WPPT as well as its performance during large romps...... (swings) in power output. In addition to this, detected large ramps are studied in detail and categorized. WPPT combines wind speed and direction forecasts from the Australian Bureau of Meteorology regional numerical weather prediction model, MesoLAPS, with real-time wind power observations to make hourly...... forecasts of the wind farm power output. The general performances of MesoLAPS and WPPTore evaluated over I year using the root mean square error (RMSE). The errors are significantly lower than for basic benchmark forecasts but higher than for many other WPPT installations, where the site conditions...

  1. Investigation of Wind Turbine Rotor Concepts for Offshore Wind Farms

    International Nuclear Information System (INIS)

    Ceyhan, Özlem; Grasso, Francesco

    2014-01-01

    Current plans in offshore wind energy developments call for further reduction of cost of energy. In order to contribute to this goal, several wind turbine rotor concepts have been investigated. Assuming the future offshore wind turbines will operate only in the offshore wind farms, the rotor concepts are not only evaluated for their stand-alone performances and their potential in reducing the loads, but also for their performance in an offshore wind farm. In order to do that, the 10MW reference wind turbine designed in Innwind.EU project is chosen as baseline. Several rotor parameters have been modified and their influences are investigated for offshore wind turbine design purposes. This investigation is carried out as a conceptual parametrical study. All concepts are evaluated numerically with BOT (Blade optimisation tool) software in wind turbine level and with Farmflow software in wind farm level for two wind farm layouts. At the end, all these concepts are compared with each other in terms of their advantages and disadvantages

  2. Large-Eddy Simulation of Atmospheric Boundary-Layer Flow Through a Wind Farm Sited on Topography

    Science.gov (United States)

    Shamsoddin, Sina; Porté-Agel, Fernando

    2017-04-01

    Large-eddy simulation (LES) has recently been well validated and applied in the context of wind turbines over flat terrain; however, to date its accuracy has not been tested systematically in the case of turbine-wake flows over topography. Here, we investigate the wake flow in a wind farm situated on hilly terrain using LES for a case where wind-tunnel experimental data are available. To this end, first boundary-layer flow is simulated over a two-dimensional hill in order to characterize the spatial distribution of the mean velocity and the turbulence statistics. A flow simulation is then performed through a wind farm consisting of five horizontal-axis wind turbines sited over the same hill in an aligned layout. The resulting flow characteristics are compared with the former case, i.e., without wind turbines. To assess the validity of the simulations, the results are compared with the wind-tunnel measurements. It is found that LES can reproduce the flow field effectively, and, specifically, the speed-up over the hilltop and the velocity deficit and turbulence intensity enhancement induced by the turbines are well captured by the simulations. Besides, the vertical profiles of the mean velocity and turbulence intensity at different streamwise positions match well those for the experiment. In addition, another numerical experiment is carried out to show how higher (and more realistic) thrust coefficients of the turbines lead to stronger wakes and, at the same time, higher turbulence intensities.

  3. Solutions to raptor-wind farm interactions

    Energy Technology Data Exchange (ETDEWEB)

    Madders, M.; Walker, D.G. [CRE Energy Ltd., Scottish Power, Glasgow (United Kingdom)

    2000-07-01

    Wind energy developments in the uplands have the potential to adversely impact upon a number of raptor species by lowering survival and reproductive rates. In many cases, wind farms are proposed in areas where raptors are already under pressure from existing land uses, notably sheep grazing and forestry. This paper summarises the approach used to assess the impact of a 30MW wind farm on a pair of golden eagles in the Kintyre peninsula, Scotland. We outline the method being used to manage habitats for the benefit of the eagles and their prey. By adopting management practices that are both wide-scale and long-term, we aim to reduce the impact to the wind farm to levels considered acceptable by the conservation agencies, and improve breeding productivity of the eagles using the wind farm. The implications of this innovative approach for future raptor--wind farm interactions are discussed. (Author)

  4. Dispersive stresses in wind farms

    Science.gov (United States)

    Segalini, Antonio; Braunbehrens, Robert; Hyvarinen, Ann

    2017-11-01

    One of the most famous models of wind farms is provided by the assumption that the farm can be approximated as a horizontally-homogeneous forest canopy with vertically-varying force intensity. By means of this approximation, the flow-motion equations become drastically simpler, as many of the three-dimensional effects are gone. However, the application of the horizontal average operator to the RANS equations leads to the appearance of new transport terms (called dispersive stresses) originating from the horizontal (small-scale) variation of the mean velocity field. Since these terms are related to the individual turbine signature, they are expected to vanish outside the roughness sublayer, providing a definition for the latter. In the present work, an assessment of the dispersive stresses is performed by means of a wake-model approach and through the linearised code ORFEUS developed at KTH. Both approaches are very fast and enable the characterization of a large number of wind-farm layouts. The dispersive stress tensor and its effect on the turbulence closure models are investigated, providing guidelines for those simulations where it is impossible to resolve the farm at a turbine scale due to grid requirements (as, for instance, mesoscale simulations).

  5. Wind model for low frequency power fluctuations in offshore wind farms

    DEFF Research Database (Denmark)

    Vigueras-Rodríguez, A.; Sørensen, Poul Ejnar; Cutululis, Nicolaos Antonio

    2010-01-01

    of hours, taking into account the spectral correlation between different wind turbines. The modelling is supported by measurements from two large wind farms, namely Nysted and Horns Rev. Measurements from individual wind turbines and meteorological masts are used. Finally, the models are integrated......This paper investigates the correlation between the frequency components of the wind speed Power Spectral Density. The results extend an already existing power fluctuation model that can simulate power fluctuations of wind power on areas up to several kilometers and for time scales up to a couple...

  6. Performance assessment of Portuguese wind farms: Ownership and managerial efficiency

    International Nuclear Information System (INIS)

    Pestana Barros, Carlos; Sequeira Antunes, Olinda

    2011-01-01

    This paper analyzes ownership and unobserved managerial ability as factors affecting the performance of a representative sample of Portuguese wind farms by means of frontier models. These farms are ranked according to their technical efficiency during the period 2004-2008 and homogenous and heterogeneous variables are disentangled in the cost function, which leads us to advise the implementation of common policies as well as policies by segments. Economic implications arising from the study are also considered. - Research highlights: → Wind farms are heterogeneous displaying distinct ownership and managerial characteristics that affect efficiency. → Managerial practices has a positive impact on the efficiency. → Ownership has a positive impact on the efficiency. Large wind farms are more efficient.

  7. Monitoring, modeling and mitigating impacts of wind farms on local meteorology

    Science.gov (United States)

    Baidya Roy, Somnath; Traiteur, Justin; Kelley, Neil

    2010-05-01

    Wind power is one of the fastest growing sources of energy. Most of the growth is in the industrial sector comprising of large utility-scale wind farms. Recent modeling studies have suggested that such wind farms can significantly affect local and regional weather and climate. In this work, we present observational evidence of the impact of wind farms on near-surface air temperatures. Data from perhaps the only meteorological field campaign in an operational wind farm shows that downwind temperatures are lower during the daytime and higher at night compared to the upwind environment. Corresponding radiosonde profiles at the nearby Edwards Air Force Base WMO meteorological station show that the diurnal environment is unstable while the nocturnal environment is stable during the field campaign. This behavior is consistent with the hypothesis proposed by Baidya Roy et al. (JGR 2004) that states that turbulence generated in the wake of rotors enhance vertical mixing leading to a warming/cooling under positive/negative potential temperature lapse rates. We conducted a set of 306 simulations with the Regional Atmospheric Modeling System (RAMS) to test if regional climate models can capture the thermal effects of wind farms. We represented wind turbines with a subgrid parameterization that assumes rotors to be sinks of momentum and sources of turbulence. The simulated wind farms consistently generated a localized warming/cooling under positive/negative lapse rates as hypothesized. We found that these impacts are inversely correlated with background atmospheric boundary layer turbulence. Thus, if the background turbulence is high due to natural processes, the effects of additional turbulence generated by wind turbine rotors are likely to be small. We propose the following strategies to minimize impacts of wind farms: • Engineering solution: design rotors that generate less turbulence in their wakes. Sensitivity simulations show that these turbines also increase the

  8. Reliability evaluation for offshore wind farms

    DEFF Research Database (Denmark)

    Zhao, Menghua; Blåbjerg, Frede; Chen, Zhe

    2005-01-01

    In this paper, a new reliability index - Loss Of Generation Ratio Probability (LOGRP) is proposed for evaluating the reliability of an electrical system for offshore wind farms, which emphasizes the design of wind farms rather than the adequacy for specific load demand. A practical method...... to calculate LOGRP of offshore wind farms is proposed and evaluated....

  9. Grid connection of active stall wind farms using a VSC based DC transmission system

    DEFF Research Database (Denmark)

    Iov, F.; Sørensen, Poul Ejnar; Hansen, A.D.

    2005-01-01

    Currently, there is an increasing trend to connect large MW wind farms to the transmission system. Requirements that focus on the influence of the farms on the grid stability and power quality, and on the control capabilities of wind farms have already been established. The main trends of modern...... wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly fed induction generators. Using power electronics the control capabilities of these wind turbines/farms are extended and thus the grid requirements...... are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid have less control capabilities. These wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection...

  10. Variable frequency operation of active stall wind farms using a dc connection to grid

    DEFF Research Database (Denmark)

    Iov, Florin; Blaabjerg, Frede; Sorensen, Poul

    2005-01-01

    Currently, there is an increasing trend to connect large MW wind farms to the transmISSIon system. Requirements that focus on the influence of the farms on the grid stability and power quality, and on the control capabilities of wind farms have already been established. The main trends of modern...... wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics the control capabilities of these wind turbines/farms are extended and thus the grid requirements...... are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid have less control capabilities. These wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection...

  11. Reducing Harmonic Instability and Resonance Problems in PMSG Based Wind Farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2018-01-01

    Unlike conventional power systems where harmonic resonances are coming from passive inductive and capacitive elements, large-scale power electronic systems like wind farms present a more complex system, where the fast dynamics of the power electronic converters may present an inductive or capacit......Unlike conventional power systems where harmonic resonances are coming from passive inductive and capacitive elements, large-scale power electronic systems like wind farms present a more complex system, where the fast dynamics of the power electronic converters may present an inductive...... or capacitive behavior. Therefore, the interactions between the fast controllers of the power converters and the passive elements may lead to harmonic instability and new resonances at various frequencies. This paper presents an optimum design technique for the Wind Turbine (WT) inner controllers in a PMSG...... based wind farm in order to reduce the number of resonances and to mitigate harmonic instability. In the approach, a PMSG based wind farm is modeled as a Multi-Input Multi-Output (MIMO) dynamic system by modeling the high bandwidth control loops of the power converters. Resonance frequencies...

  12. The Lake Turkana wind farm project

    Energy Technology Data Exchange (ETDEWEB)

    Burlando, M.; Durante, F. [DEWI GmbH, Genoa (Italy); Claveri, L. [DEWI GmbH, Oldenburg (Germany)

    2010-08-15

    The Lake Turkana wind farm is one of the largest wind farm projects to be realised in the African Continent, and the first of its kind in Kenya. After its full commissioning in 2012, the wind farm will be generating 300 MW of clean power almost steadily thanks to the very peculiar characteristics of the wind climate of north-western Kenya. Until now, only northern African countries such as Morocco and Egypt had used wind power for commercial purposes on the continent. Projects are now beginning to bloom south of the Sahara as governments realise that harnessing the vast wind potential can efficiently meet the growing demand of electric power. With the Lake Turkana wind farm project and other minor projects, Kenya is trying to lead the way. The project consists of building 365 wind turbines Vestas V52 of hub height 45 m and nominal power 850 kW, corresponding to about 30% of Kenya's current installed power. The project includes also reinforcing 200 km of roads and bridges to transport the wind turbines from the Indian Ocean port of Mombasa to the northwestern Kenya, and adding more than 400 km of transmission lines and several substations to connect the wind farm and supply power to the national electric grid. (orig.)

  13. Transient stability risk assessment of power systems incorporating wind farms

    DEFF Research Database (Denmark)

    Miao, Lu; Fang, Jiakun; Wen, Jinyu

    2013-01-01

    fed induction generator has been established. Wind penetration variation and multiple stochastic factors of power systems have been considered. The process of transient stability risk assessment based on the Monte Carlo method has been described and a comprehensive risk indicator has been proposed......Large-scale wind farm integration has brought several aspects of challenges to the transient stability of power systems. This paper focuses on the research of the transient stability of power systems incorporating with wind farms by utilizing risk assessment methods. The detailed model of double....... An investigation has been conducted into an improved 10-generator 39-bus system with a wind farm incorporated to verify the validity and feasibility of the risk assessment method proposed....

  14. Local non-market quality of life dynamics in new wind farms communities

    International Nuclear Information System (INIS)

    Kahn, Matthew E.

    2013-01-01

    The environmental benefits from generating electricity using renewable power are well known. Both wind farms and large scale solar installations require significant amounts of land to generate such power. Private land holders gain from leasing and selling land to renewable power generators but how are nearby neighbors and county residents affected? This study uses data from West Texas and documents that wind farm county's residents have gained from recent place based investments in wind farms. County property tax rates have fallen and public school quality has improved in those counties where wind farms have been built. Based on the local fiscal data, local school quality data and local ambient air pollution data, renewable power is a “better neighbor” than conventional fossil fuel fired power plants. - Highlights: • Rural counties with wind farms have lower property tax rates than neighbor counties. • Wind farm counties have lower student–teacher ratios. • Ambient air pollution levels are higher near fossil fuel fired power plants

  15. IEA Wind Task 26: Offshore Wind Farm Baseline Documentation

    Energy Technology Data Exchange (ETDEWEB)

    Smart, Gavin [Offshore Renewable Energy Catapult, Blyth, Northumberland (United Kingdom); Smith, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Warner, Ethan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sperstad, Iver Bakken [SINTEF Energy Research, Trondheim (Norway); Prinsen, Bob [Ecofys, Utrecht (Netherlands). TKI Wind Op Zee; Lacal-Arantegui, Roberto [European Commission Joint Research Centre (JRC), Brussels (Belgium)

    2016-06-02

    This document has been produced to provide the definition and rationale for the Baseline Offshore Wind Farm established within IEA Wind Task 26--Cost of Wind Energy. The Baseline has been developed to provide a common starting point for country comparisons and sensitivity analysis on key offshore wind cost and value drivers. The baseline project reflects an approximate average of the characteristics of projects installed between 2012 and 2014, with the project life assumed to be 20 years. The baseline wind farm is located 40 kilometres (km) from construction and operations and maintenance (O&M) ports and from export cable landfall. The wind farm consists of 100 4-megawatt (MW) wind turbines mounted on monopile foundations in an average water depth of 25 metres (m), connected by 33-kilovolt (kV) inter-array cables. The arrays are connected to a single offshore substation (33kV/220kV) mounted on a jacket foundation, with the substation connected via a single 220kV export cable to an onshore substation, 10km from landfall. The wind farm employs a port-based O&M strategy using crew-transfer vessels.

  16. Turbine Control Strategies for Wind Farm Power Optimization

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Göçmen Bozkurt, Tuhfe; Giebel, Gregor

    2015-01-01

    In recent decades there has been increasing interest in green energies, of which wind energy is the most important one. In order to improve the competitiveness of the wind power plants, there are ongoing researches to decrease cost per energy unit and increase the efficiency of wind turbines...... and wind farms. One way of achieving these goals is to optimize the power generated by a wind farm. One optimization method is to choose appropriate operating points for the individual wind turbines in the farm. We have made three models of a wind farm based on three difference control strategies...... the generated power by changing the power reference of the individual wind turbines. We use the optimization setup to compare power production of the wind farm models. This paper shows that for the most frequent wind velocities (below and around the rated values), the generated powers of the wind farms...

  17. Regulation techniques for smoothing active power in aggregated wind farms distributed within Spain

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Martinez, Sergio; Vigueras-Rodriguez, Antonio; Gomez-Lazaro, Emilio [Universidad de Castilla-La Mancha, Albacete (Spain). Renewable Energy Research Inst.

    2009-07-01

    With the increasing production of wind power worldwide, power fluctuations have an impact on power system operation and costs. Power systems with high wind penetration gives rise to concerns about the adverse effects of wind farms on power operations and its staability. The integration of the power produced by wind farms is evaluated through ramp rates calculated as suggested by Parson et al. The worst cases regarding the power system are the most negative ramp rates in the Wind Farm, where the Power System has to compensate such drops in the wind power production. In most onshore wind farms production fluctuates much less than in offshore farms, due to two main reasons. First, offshore wind turbines are collected in a more reduced area, so fluctuations are more correlated. In addition, offshore meteorological conditions are often different than onshore. Furthermore, the variability of wind power is reduced when looking at a large interconnected sytem with geographically dispersed wind power production. This paper deals with a comparison of the smoothed out variability of wind power production time series for the single and aggregated wind farms, parting from their wind power production. The data analyzed come from a 1 year-period measurements of 9 wind farms spread over Spain. (orig.)

  18. Health impact of wind farms.

    Science.gov (United States)

    Kurpas, Donata; Mroczek, Bozena; Karakiewicz, Beata; Kassolik, Krzysztof; Andrzejewski, Waldemar

    2013-01-01

    Wind power is employed worldwide as an alternative source of energy. At the same time, however, the health effects of wind turbines have become a matter of discussion. The purpose of this study is a critical review of available reports providing arguments both for and against the construction of wind farms. The authors also attempt to propose recommendations in accordance with the Evidence-Based Medicine (EBM) guidelines. In the case of exposure to wind farms, a randomized controlled trial (RCT) is impossible. To obtain the highest-level recommendations, analysis of case-control studies or cohort studies with control groups should be performed. Preferably, it should include geostatistical analysis conducted with the use of variograms and the kriging technique. Combinations of key words were entered into the Thomson Reuters Web of Knowledge (SM) and the Internet search engine Google. SHORT DESCRIPTION OF STATE OF THE ART: The nuisance caused by wind turbines is stereotypically linked with the noise that they produce. Nevertheless, the visual aspect of wind farms, opinions about them, and sensitivity to sound seem to be of the greater importance. To date, the direct correlations between the vicinity of modern wind farms, the noise that wind turbines make, and possible consequences to health have not been described in peer reviewed articles. Health effects are more probably associated with some environmental factors leading to annoyance or frustration. All types of studies share the same conclusion: wind turbines can provoke annoyance. As with any project involving changes in the local environment, a certain level of irritation among the population can be expected. There are elected officials and government representatives who should decide what level of social annoyance is acceptable, and whether wind power advantages outweigh its potential drawbacks. The influence of wind turbines on human emotional and physical health is a relatively new field of research. Further

  19. A Wind Farm Controller for Load and Power Optimization in a Farm

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Brand, Arno; Wisniewski, Rafal

    2011-01-01

    This paper describes the design procedure of an optimal wind farm controller. The controller optimizes the structural load and power production simultaneously, on the basis of an analytical wind farm model. The farm model delivers maps of wind, loads and energy in the wind farm. Moreover, the model...... computes the wind speed at the turbines, turbine bending moments and aerodynamic power and torque. The optimal control problem is formulated based on the model for two different wind directions. The controller determines the reference signals for each individual wind turbine controller in two scenarios...... based on low and high wind speed. In low wind speed, the reference signals for rotor speed are adjusted, taking the trade-off between power maximization and load minimization into account. In high wind speed, the power and pitch angle reference signals are determined while structural loads are minimized....

  20. The potential of wind farms

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Summaries of papers presented at the European wind energy conference on the potential of wind farms are presented. It is stated that in Denmark today, wind energy provides about 3% to the Danish electricity consumption and the wind power capacity is, according to Danish wind energy policy, expected to increase substantially in the years to come. A number of countries in Europe and elsewhere are making significant progress in this repect. Descriptions of performance are given in relation to some individual wind farms. The subjects covered concern surveys of national planning and policies regarding wind utilization and national and global development of wind turbine arrays. Papers also deal with utility and project planning, wind prediction and certification, wind loads and fatigue, wakes, noise and control. (AB).

  1. Control strategies for wind farm power optimization: LES study

    Science.gov (United States)

    Ciri, Umberto; Rotea, Mario; Leonardi, Stefano

    2017-11-01

    Turbines in wind farms operate in off-design conditions as wake interactions occur for particular wind directions. Advanced wind farm control strategies aim at coordinating and adjusting turbine operations to mitigate power losses in such conditions. Coordination is achieved by controlling on upstream turbines either the wake intensity, through the blade pitch angle or the generator torque, or the wake direction, through yaw misalignment. Downstream turbines can be adapted to work in waked conditions and limit power losses, using the blade pitch angle or the generator torque. As wind conditions in wind farm operations may change significantly, it is difficult to determine and parameterize the variations of the coordinated optimal settings. An alternative is model-free control and optimization of wind farms, which does not require any parameterization and can track the optimal settings as conditions vary. In this work, we employ a model-free optimization algorithm, extremum-seeking control, to find the optimal set-points of generator torque, blade pitch and yaw angle for a three-turbine configuration. Large-Eddy Simulations are used to provide a virtual environment to evaluate the performance of the control strategies under realistic, unsteady incoming wind. This work was supported by the National Science Foundation, Grants No. 1243482 (the WINDINSPIRE project) and IIP 1362033 (I/UCRC WindSTAR). TACC is acknowledged for providing computational time.

  2. A Wind Farm Electrical Systems Evaluation with EeFarm-II

    NARCIS (Netherlands)

    Pierik, J.; Axelsson, U.; Eriksson, E.; Salomonsson, D.; Bauer, P.; Czech, B.

    2010-01-01

    EeFarm-II is used to evaluate 13 different electrical systems for a 200 MW wind farm with a 100 km connection to shore. The evaluation is based on component manufacturer data of 2009. AC systems are compared to systems with DC connections inside the wind farm and DC connection to shore. Two options

  3. Evaluating the impact of electrical grid connection on the wind turbine performance for Hofa wind farm scheme in Jordan

    International Nuclear Information System (INIS)

    Abderrazzaq, M.H.; Aloquili, O.

    2008-01-01

    The growth of wind energy is attributed to the development of turbine size and the increase in number of units in each wind farm. The current modern design of large wind turbines (WT) is directed towards producing efficient, sensitive and reliable units. To achieve this goal, modern turbines are equipped with several devices which are operated with highly advanced electronic circuits. Sensing instruments, measuring devices and control processes of major systems and subsystems are based on various types of electronic apparatus and boards. These boards are very sensitive to the voltage variations caused by abnormal conditions in both the turbine itself and the electric grid to which the wind farm is connected. This paper evaluates wind farm records and proposes a number of methods to overcome such obstacles associated with the design of large wind turbines. Several cases of grid abnormality such as sudden feeder interruption due to the short circuit, network disconnection, voltage variation and circuit breaker opening affecting wind turbines operation and availability are classified and presented. The weight of such impact is determined for each type of disturbances associated with electronic problems in the wind turbine. Wind turbine performance at Hofa wind farm scheme in Jordan is taken as a case study

  4. Wind Farm Wake: The 2016 Horns Rev Photo Case

    Directory of Open Access Journals (Sweden)

    Charlotte Bay Hasager

    2017-03-01

    Full Text Available Offshore wind farm wakes were observed and photographed in foggy conditions at Horns Rev 2 on 25 January 2016 at 12:45 UTC. These new images show highly contrasting conditions regarding the wind speed, turbulence intensity, atmospheric stability, weather conditions and wind farm wake development as compared to the Horns Rev 1 photographs from 12 February 2008. The paper examines the atmospheric conditions from satellite images, radiosondes, lidar and wind turbine data and compares the observations to results from atmospheric meso-scale modelling and large eddy simulation. Key findings are that a humid and warm air mass was advected from the southwest over cold sea and the dew-point temperature was such that cold-water advection fog formed in a shallow layer. The flow was stably stratified and the freestream wind speed was 13 m/s at hub height, which means that most turbines produced at or near rated power. The wind direction was southwesterly and long, narrow wakes persisted several rotor diameters downwind of the wind turbines. Eventually mixing of warm air from aloft dispersed the fog in the far wake region of the wind farm.

  5. Efficiency assessment of wind farms in China using two-stage data envelopment analysis

    International Nuclear Information System (INIS)

    Wu, Yunna; Hu, Yong; Xiao, Xinli; Mao, Chunyu

    2016-01-01

    Highlights: • The efficiency of China’s wind farms is assessed by data envelopment analysis. • Tobit model is used to analyze the impact of uncontrollable factors on efficiency. • Sensitivity analysis is conducted to verify the stability of evaluation results. • Efficiency levels of Chinese wind farms are relatively high in general. • Age and wind curtailment rate negatively affect the productive efficiency. - Abstract: China has been the world’s leader in wind power capacity due to the promotion of favorable policies. Given the rare research on the efficiency of China’s wind farms, this study analyzes the productive efficiency of 42 large-scale wind farms in China using a two-stage analysis. In the first stage, efficiency scores of wind farms are determined with data envelopment analysis and the sensitivity analysis is conducted to verify the robustness of efficiency calculation results. In the second stage, the Tobit regression is employed to explore the relationship between the efficiency scores and the environment variables that are beyond the control of wind farms. According to the results, all wind farms studied operate at an acceptable level. However, 50% of them overinvest in the installed capacity and about 48% have the electricity-saving potential. The most important factors affecting the efficiency of wind farms are the installed capacity and the wind power density. In addition, the age of the wind farm and the wind curtailment rate have a negative effect on productive efficiency, whereas the ownership of the wind farm has no significant effect. Findings from this study may be helpful for stakeholders in the wind industry to select wind power projects, optimize operational strategies and make related policies.

  6. Optimization of Wind Farm Layout in Complex Terrain

    DEFF Research Database (Denmark)

    Xu, Chang; Yang, Jianchuan; Li, Chenqi

    2013-01-01

    Microscopic site selection for wind farms in complex terrain is a technological difficulty in the development of onshore wind farms. This paper presented a method for optimizing wind farm layout in complex terrain. This method employed Lissaman and Jensen wake models, took wind velocity distribut......Microscopic site selection for wind farms in complex terrain is a technological difficulty in the development of onshore wind farms. This paper presented a method for optimizing wind farm layout in complex terrain. This method employed Lissaman and Jensen wake models, took wind velocity...... are subject to boundary conditions and minimum distance conditions. The improved genetic algorithm (GA) for real number coding was used to search the optimal result. Then the optimized result was compared to the result from the experienced layout method. Results show the advantages of the present method...

  7. Improvement of voltage stability in wind farm connection to distribution network using FACTS devices

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, V.; Kahrobaee, S.; Afsharnia, S. [School of Electrical and Computer Engineering, ECE, University of Tehran (Iran)

    2006-07-01

    Increasing capacity of connected wind power generation to utilities brings new opportunities and also problems to the utilities and customers. Evolution and analyzing of the connection conditions and effects of wind farms especially on remote areas are the main aspects of developing wind power on the utilities. The problem is that these wind turbine that mostly uses induction generators, tend to drain large amounts of VARs from the grid, potentially causing low voltage and maybe voltage stability problems for the utility owner, especially in the case of large load variation on distribution feeder. To investigate the impact of large wind farms on power system voltage stability, one of the Iran's wind farms is modeled in DIgSILENT software and the simulation results shows the effect of using FACTS devices including SVC and STATCOM on power system performance. (orig.)

  8. New Models for Maintenance of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Petersen, Kristian R.

    component that was causing a large amount of downtime were identified. Further analysis with the Reliability-Centred Maintenance concept helped determine the most appropriate maintenance strategy. In the final perspective, long-term strategic decisions were the focus. Asset Management and especially Asset...... Life-Cycle Management were studied using a case study. The case study analysis was used to generate strategies to help managers perform maintenance more proactively and to prepare the management of the offshore wind farm turbines for the future. Existing literature on Asset Life-Cycle Management has......Operations and maintenance (O&M) processes are important for keeping offshore wind turbines in operation. Costs related to such activities constitute approximately 30% of the lifetime cost of an offshore wind farm project. Currently, the offshore wind energy industry has shown a rapid increase...

  9. Effects of the Tunoe Knob offshore wind farm on birdlife

    International Nuclear Information System (INIS)

    Guillemette, M.; Kyed Larsen, J.; Clausager, I.

    1997-01-01

    As part of the plans of the Danish government to expand offshore wind energy production, The Ministry of Environment and Energy, in collaboration with the Danish power companies, initiated a three-year study of the effects of the Tunoe Knob offshore wind farm on bird life. The aim of this study was to investigate the potential conflict between offshore wind farms and water birds. Danish coastal waters support very large, internationally important concentrations of moulting, migrating and wintering water birds which depend on shallow water areas as major feeding habitats. The wind farm was established at Tunoe Knob, a shoal in Aarhus Bugt, and consisted of ten 500 kW turbines erected in 3-5 m of water during the late summer of 1995. All studies were carried out during the winter period, and results are reported for eider Somateria mollissima and common scoter Melanitta nigra, which composed the great majority of the bird population. In the part of Tunoe knob where the wind farm was build, eider numbers decreased markedly over the study period. However, this decline was comparable to that observed on other parts of Tunoe Knob. Furthermore, detailed mapping showed a high degree of annual and within season variation in spatial distribution over the area, including occurrence in the immediate vicinity of the wind farm. These results suggest that the observed changes in eider numbers in the wind farm area were due to natural variation. (EG) 21 refs

  10. Repowering of wind farms - A case study

    Energy Technology Data Exchange (ETDEWEB)

    Nivedh, B.S. [Quality Engineering and Software Technologies, Bangalore (India); Devi, R.P.K. [College of Engineering. Power Systems Engineering, Guindy (India); Sreevalsan, E. [Gamesa Wind Turbines India Private Limited, Chennai (India)

    2012-07-01

    The main objective of the study is to devise a method for assessing the repowering potential and to improve the energy output from the wind farms and also to understand the impact on the power quality due to repowering. With repowering, the first-generation wind turbines can be replaced with modern multi-megawatt wind turbines. To carry-out the study an old wind farm located at Kayathar, Tamilnadu is selected. The wind farm was commissioned in 1990's with a capacity of 7.35MW, which consists of 36 Wind Turbines each with the capacity of 200kW and 225kW. The present annual energy generation of the wind farm is 7350MWhr with the plant load factor of 11.41%. The intent of this study is to predict the annual energy output of the wind farm after the repowering using WAsP (Wind Atlas Analysis Application Program). Further this study analyses the power quality issues of the various Wind Turbines. In addition, the main feeder, in which the wind farm which is taken for the study also modeled and the impact on power quality due to repowering also studied. Simulations were carried out using MATLAB. The results are analyzed to understand the significance of repowering to overcome the energy crisis of the nation since the best locations for wind in India are occupied by old wind turbines. The following are the observations and conclusions from the above study. Plant load factor (PLF) increased to 24 %, Energy yield increased to more than 4 times and the capacity of the wind farm became double. And in the view of power quality, comparing to the existing Feeder, Repowered Feeder having less reactive power consumption, voltage variations and flickers except the harmonic distortion. (Author)

  11. Fish benefits from offshore wind farm development

    DEFF Research Database (Denmark)

    Leonhard, Simon B.; Stenberg, Claus; Støttrup, Josianne

    2013-01-01

    The studies up until 2006 showed few effects on the fish fauna that could be attributed to the establishment and operation of the wind farms. Fish abundance and diversity were not higher inside the wind farms than in the areas outside the wind farms. One obvious reason for this could be that the ...

  12. Wind Farm Wake: The Horns Rev Photo Case

    Directory of Open Access Journals (Sweden)

    Pierre-Elouan Réthoré

    2013-02-01

    Full Text Available The aim of the paper is to examine the nowadays well-known wind farm wake photographs taken on 12 February 2008 at the offshore Horns Rev 1 wind farm. The meteorological conditions are described from observations from several satellite sensors quantifying clouds, surface wind vectors and sea surface temperature as well as ground-based information at and near the wind farm, including Supervisory Control and Data Acquisition (SCADA data. The SCADA data reveal that the case of fog formation occurred 12 February 2008 on the 10:10 UTC. The fog formation is due to very special atmospheric conditions where a layer of cold humid air above a warmer sea surface re-condensates to fog in the wake of the turbines. The process is fed by warm humid air up-drafted from below in the counter-rotating swirl generated by the clock-wise rotating rotors. The condensation appears to take place primarily in the wake regions with relatively high axial velocities and high turbulent kinetic energy. The wind speed is near cut-in and most turbines produce very little power. The rotational pattern of spiraling bands produces the large-scale structure of the wake fog.

  13. Visual disamenities from off-shore wind farms in Denmark

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Dubgaard, Alex; Tranberg, Jesper

    2006-01-01

    Expansion of the off-shore wind power plays a significant role in the energy policies of many EU countries. However, off-shore wind farms create visual disamenities. These disamenities can be reduced by locating wind farms at larger distances from the coast – and accepting higher costs per k......Wh produced. Base on the choices among alternative wind farm outlays, the preferences for reducing visual disamenities of off-shore wind farms were elicited using the Choice Experiment Method. The results show a clear picture; the respondents in three independent samples are willing to pay for mowing future...... off-shore wind farms away from the shore to reduce the wind farms visibility. However, the results also denote that the preferences vary with regards to the experiences with visual disamenities of off-shore wind farms. The respondents Horns Revs sample, where the off-shore wind farm is located...

  14. Towards uncovering the structure of power fluctuations of wind farms.

    Science.gov (United States)

    Liu, Huiwen; Jin, Yaqing; Tobin, Nicolas; Chamorro, Leonardo P

    2017-12-01

    The structure of the turbulence-driven power fluctuations in a wind farm is fundamentally described from basic concepts. A derived tuning-free model, supported with experiments, reveals the underlying spectral content of the power fluctuations of a wind farm. It contains two power-law trends and oscillations in the relatively low- and high-frequency ranges. The former is mostly due to the turbulent interaction between the flow and the turbine properties, whereas the latter is due to the advection between turbine pairs. The spectral wind-farm scale power fluctuations Φ_{P} exhibit a power-law decay proportional to f^{-5/3-2} in the region corresponding to the turbulence inertial subrange and at relatively large scales, Φ_{P}∼f^{-2}. Due to the advection and turbulent diffusion of large-scale structures, a spectral oscillation exists with the product of a sinusoidal behavior and an exponential decay in the frequency domain.

  15. Power-Production Diagnostic Tools for Low-Density Wind Farms with Applications to Wake Steering

    Science.gov (United States)

    Takle, E. S.; Herzmann, D.; Rajewski, D. A.; Lundquist, J. K.; Rhodes, M. E.

    2016-12-01

    Hansen (2011) provided guidelines for wind farm wake analysis with applications to "high density" wind farms (where average distance between turbines is less than ten times rotor diameter). For "low-density" (average distance greater than fifteen times rotor diameter) wind farms, or sections of wind farms we demonstrate simpler sorting and visualization tools that reveal wake interactions and opportunities for wind farm power prediction and wake steering. SCADA data from a segment of a large mid-continent wind farm, together with surface flux measurements and lidar data are subjected to analysis and visualization of wake interactions. A time-history animated visualization of a plan view of power level of individual turbines provides a quick analysis of wake interaction dynamics. Yaw-based sectoral histograms of enhancement/decline of wind speed and power from wind farm reference levels reveals angular width of wake interactions and identifies the turbine(s) responsible for the power reduction. Concurrent surface flux measurements within the wind farm allowed us to evaluate stability influence on wake loss. A one-season climatology is used to identify high-priority candidates for wake steering based on estimated power recovery. Typical clearing prices on the day-ahead market are used to estimate the added value of wake steering. Current research is exploring options for identifying candidate locations for wind farm "build-in" in existing low-density wind farms.

  16. Sensitivity analysis of floating offshore wind farms

    International Nuclear Information System (INIS)

    Castro-Santos, Laura; Diaz-Casas, Vicente

    2015-01-01

    Highlights: • Develop a sensitivity analysis of a floating offshore wind farm. • Influence on the life-cycle costs involved in a floating offshore wind farm. • Influence on IRR, NPV, pay-back period, LCOE and cost of power. • Important variables: distance, wind resource, electric tariff, etc. • It helps to investors to take decisions in the future. - Abstract: The future of offshore wind energy will be in deep waters. In this context, the main objective of the present paper is to develop a sensitivity analysis of a floating offshore wind farm. It will show how much the output variables can vary when the input variables are changing. For this purpose two different scenarios will be taken into account: the life-cycle costs involved in a floating offshore wind farm (cost of conception and definition, cost of design and development, cost of manufacturing, cost of installation, cost of exploitation and cost of dismantling) and the most important economic indexes in terms of economic feasibility of a floating offshore wind farm (internal rate of return, net present value, discounted pay-back period, levelized cost of energy and cost of power). Results indicate that the most important variables in economic terms are the number of wind turbines and the distance from farm to shore in the costs’ scenario, and the wind scale parameter and the electric tariff for the economic indexes. This study will help investors to take into account these variables in the development of floating offshore wind farms in the future

  17. Gravity Waves and Wind-Farm Efficiency in Neutral and Stable Conditions

    Science.gov (United States)

    Allaerts, Dries; Meyers, Johan

    2018-02-01

    We use large-eddy simulations (LES) to investigate the impact of stable stratification on gravity-wave excitation and energy extraction in a large wind farm. To this end, the development of an equilibrium conventionally neutral boundary layer into a stable boundary layer over a period of 8 h is considered, using two different cooling rates. We find that turbulence decay has considerable influence on the energy extraction at the beginning of the boundary-layer transition, but afterwards, energy extraction is dominated by geometrical and jet effects induced by an inertial oscillation. It is further shown that the inertial oscillation enhances gravity-wave excitation. By comparing LES results with a simple one-dimensional model, we show that this is related to an interplay between wind-farm drag, variations in the Froude number and the dispersive effects of vertically-propagating gravity waves. We further find that the pressure gradients induced by gravity waves lead to significant upstream flow deceleration, reducing the average turbine output compared to a turbine in isolated operation. This leads us to the definition of a non-local wind-farm efficiency, next to a more standard wind-farm wake efficiency, and we show that both can be of the same order of magnitude. Finally, an energy flux analysis is performed to further elucidate the effect of gravity waves on the flow in the wind farm.

  18. Effects of turbine spacing on the power output of extended wind-farms

    NARCIS (Netherlands)

    Stevens, Richard Johannes Antonius Maria; Gayme, Dennice F.; Meneveau, Charles

    2016-01-01

    We present results from large eddy simulations of extended wind-farms for several turbine configurations with a range of different spanwise and streamwise spacing combinations. The results show that for wind-farms arranged in a staggered configuration with spanwise spacings in the range ≈[3.5,8]D,

  19. Collection Network Cable Routing and Wake Losses Optimization in Offshore Wind Farms

    NARCIS (Netherlands)

    S.F. Rodrigues; P. Bauer (Pavol); P.A.N. Bosman (Peter); J. Pierik

    2014-01-01

    htmlabstractOffshore wind farms with high installed capacities and located further from the shore are starting to be built by northern European countries. Furthermore, it is expected that by 2020, several dozens of large offshore wind farms will be built in the Baltic, Irish and North seas. These

  20. Optimal Turbine Allocation for Offshore and Onshore Wind Farms

    DEFF Research Database (Denmark)

    Fischetti, Martina; Fischetti, Matteo; Monaci, Michele

    2016-01-01

    . In particular, lots of money and energy are spent on the optimal design of wind farms, as an efficient use of the available resources is instrumental for their economical success. In the present paper we address the optimization of turbine positions, which is one of the most relevant problems in the design...... of a wind farm, and propose a heuristic approach based on Mixed-Integer Linear Programming techniques. Computational results on very large scale instances prove the practical viability of the approach....

  1. Wind farms production: Control and prediction

    Science.gov (United States)

    El-Fouly, Tarek Hussein Mostafa

    Wind energy resources, unlike dispatchable central station generation, produce power dependable on external irregular source and that is the incident wind speed which does not always blow when electricity is needed. This results in the variability, unpredictability, and uncertainty of wind resources. Therefore, the integration of wind facilities to utility electrical grid presents a major challenge to power system operator. Such integration has significant impact on the optimum power flow, transmission congestion, power quality issues, system stability, load dispatch, and economic analysis. Due to the irregular nature of wind power production, accurate prediction represents the major challenge to power system operators. Therefore, in this thesis two novel models are proposed for wind speed and wind power prediction. One proposed model is dedicated to short-term prediction (one-hour ahead) and the other involves medium term prediction (one-day ahead). The accuracy of the proposed models is revealed by comparing their results with the corresponding values of a reference prediction model referred to as the persistent model. Utility grid operation is not only impacted by the uncertainty of the future production of wind farms, but also by the variability of their current production and how the active and reactive power exchange with the grid is controlled. To address this particular task, a control technique for wind turbines, driven by doubly-fed induction generators (DFIGs), is developed to regulate the terminal voltage by equally sharing the generated/absorbed reactive power between the rotor-side and the gridside converters. To highlight the impact of the new developed technique in reducing the power loss in the generator set, an economic analysis is carried out. Moreover, a new aggregated model for wind farms is proposed that accounts for the irregularity of the incident wind distribution throughout the farm layout. Specifically, this model includes the wake effect

  2. Wake effects of large offshore wind farms on the mesoscale atmosphere

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    to the fact that its typical horizontal grid spacing is on the order of 2km, the energy extracted by the turbine, as well as the wake development inside the turbine-containing grid-cells, are not described explicitly, but are parametrized as another sub-grid scale process. In order to appropriately capture...... the wind farm wake recovery and its direction, two properties are important, the total energy extracted by the wind farm and its velocity deficit distribution. In the considered parametrization the individual turbines apply a thrust dependent on a local sub grid scale velocity, which is influenced...... by the up-stream turbines. For the sub-grid scale velocity deficit, the entrainment from the free atmospheric flow into the wake region, is taken into account. Furthermore, since the model horizontal distance is several times larger then the turbine diameter, it has been assumed that the generated...

  3. Reducing Turbine Mechanical Loads Using Flow Model-Based Wind Farm Controller

    DEFF Research Database (Denmark)

    Kazda, Jonas; Cutululis, Nicolaos Antonio

    Cumulated O&M costs of offshore wind farms are comparable with wind turbine CAPEX of such wind farm. In wind farms, wake effects can result in up to 80% higher fatigue loads at downstream wind turbines [1] and consequently larger O&M costs. The present work therefore investigates to reduce...... these loads during the provision of grid balancing services using optimal model-based wind farm control. Wind farm controllers coordinate the operating point of wind turbines in a wind farm in order to achieve a given objective. The investigated objective of the control in this work is to follow a total wind...... farm power reference while reducing the tower bending moments of the turbines in the wind farm. The wind farm controller is tested on a 8 turbine array, which is representative of a typical offshore wind farm. The operation of the wind farm is simulated using the dynamic wind farm simulation tool S imWind...

  4. Power control of a wind farm with active stall wind turbines and AC grid connection

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul; Iov, Florin

    both the control on wind turbine level as well as the central control on the wind farm level. The ability of active stall wind farms with AC grid connection to regulate the power production to the reference power ordered by the operators is assessed and discussed by means of simulations.......This paper describes the design of a centralised wind farm controller for a wind farm made-up exclusively of active stall wind turbines with AC grid connection. The overall aim of such controller is to enable the wind farms to provide the best grid support. The designed wind farm control involves...

  5. Anholt offshore wind farm winds investigated from satellite images

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Volker, Patrick

    , i.e. before the wind farm was constructed. Based on these data the wind resource is estimated. Concurrent Sentinel-1 SAR data and available SCADA and lidar data, kindly provided by DONG Energy and partners, for the period January 2013 to June 2015 account for ~70 images, while ~300 images...... are available for Sentinel-1 from July 2015 to February 2017. The Sentinel-1 wind maps are investigated for wind farm wake effects. Furthermore the results on wind resources and wakes are compared to the SCADA and model results from WRF, Park, Fuga and RANS models....

  6. Could Crop Height Affect the Wind Resource at Agriculturally Productive Wind Farm Sites?

    Science.gov (United States)

    Vanderwende, Brian; Lundquist, Julie K.

    2016-03-01

    The collocation of cropland and wind turbines in the US Midwest region introduces complex meteorological interactions that could influence both agriculture and wind-power production. Crop management practices may affect the wind resource through alterations of land-surface properties. We use the weather research and forecasting (WRF) model to estimate the impact of crop height variations on the wind resource in the presence of a large turbine array. A hypothetical wind farm consisting of 121 1.8-MW turbines is represented using the WRF model wind-farm parametrization. We represent the impact of selecting soybeans rather than maize by altering the aerodynamic roughness length in a region approximately 65 times larger than that occupied by the turbine array. Roughness lengths of 0.1 and 0.25 m represent the mature soy crop and a mature maize crop, respectively. In all but the most stable atmospheric conditions, statistically significant hub-height wind-speed increases and rotor-layer wind-shear reductions result from switching from maize to soybeans. Based on simulations for the entire month of August 2013, wind-farm energy output increases by 14 %, which would yield a significant monetary gain. Further investigation is required to determine the optimal size, shape, and crop height of the roughness modification to maximize the economic benefit and minimize the cost of such crop-management practices. These considerations must be balanced by other influences on crop choice such as soil requirements and commodity prices.

  7. Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

    OpenAIRE

    Ju Feng; Wen Zhong Shen

    2015-01-01

    Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distributions of wind speed and wind direction, which is based on the parameters of sector-wise Weibull distributions and interpolations between direction sectors. It is applied to the wind measurement data a...

  8. Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2015-01-01

    Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distribu...

  9. Modeling and Control of VSC based DC Connection for Active Stall Wind Farms to Grid

    DEFF Research Database (Denmark)

    Iov, Florin; Sorensen, Poul; Hansen, Anca-Daniela

    2005-01-01

    Currently, there is an increasing trend to connect large MW wind farms to the transmission system. Therefore the power system becomes more vulnerable and dependent on the wind energy production. At the same time requirements that focus on the influence of the farms on the grid stability and power...... quality, and on the control capabilities of wind farms have already been established. The main trends of modem wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics...... the control capabilities of these wind turbines/farms are extended and thus the grid requirements are fulfilled. However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid does not have such control capabilities. They produce maximum possible power...

  10. Modelling and Control of VSC based DC Connection for Active Stall Wind Farms to Grid

    DEFF Research Database (Denmark)

    Iov, Florin; Sørensen, Poul; Hansen, Anca Daniela

    2006-01-01

    Currently, there is an increasing trend to connect large MW wind farms to the transmission system. Therefore the power system becomes more vulnerable and dependent on the wind energy production. At the same time requirements that focus on the influence of the farms on the grid stability and power...... quality, and on the control capabilities of wind farms have already been established. The main trends of modern wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics...... the control capabilities of these wind turbines/farms are extended and thus the grid requirements are fulfilled.  However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid does not have such control capabilities. They produce maximum possible power...

  11. TOPFARM – A Tool for Wind Farm Optimization

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Réthoré, Pierre-Elouan

    2013-01-01

    TOPFARM takes the investors perspective and performs an economical optimization of a wind farm layout throughout the lifetime of the wind farm. The economical optimization approach of wind farm layout differs significantly from the traditional power output optimization. The major differences...

  12. Risk analysis for U.S. offshore wind farms: the need for an integrated approach.

    Science.gov (United States)

    Staid, Andrea; Guikema, Seth D

    2015-04-01

    Wind power is becoming an increasingly important part of the global energy portfolio, and there is growing interest in developing offshore wind farms in the United States to better utilize this resource. Wind farms have certain environmental benefits, notably near-zero emissions of greenhouse gases, particulates, and other contaminants of concern. However, there are significant challenges ahead in achieving large-scale integration of wind power in the United States, particularly offshore wind. Environmental impacts from wind farms are a concern, and these are subject to a number of on-going studies focused on risks to the environment. However, once a wind farm is built, the farm itself will face a number of risks from a variety of hazards, and managing these risks is critical to the ultimate achievement of long-term reductions in pollutant emissions from clean energy sources such as wind. No integrated framework currently exists for assessing risks to offshore wind farms in the United States, which poses a challenge for wind farm risk management. In this "Perspective", we provide an overview of the risks faced by an offshore wind farm, argue that an integrated framework is needed, and give a preliminary starting point for such a framework to illustrate what it might look like. This is not a final framework; substantial work remains. Our intention here is to highlight the research need in this area in the hope of spurring additional research about the risks to wind farms to complement the substantial amount of on-going research on the risks from wind farms. © 2015 Society for Risk Analysis.

  13. Transformer inrush current reduction through sequential energization for wind farm applications

    Energy Technology Data Exchange (ETDEWEB)

    Abdulsalam, S.; Xu, W. [Alberta Univ., Edmonton, AB (Canada)

    2008-07-01

    Wind power is considered as one of the fastest growing technologies in the power industry. The electrical configuration of a wind farm consists of long spans of medium voltage collector feeders. Each wind generator is connected to the collector circuit/feeder through either a pad mount oil filled, or a nacelle-mounted dry type transformer. All collector feeders connect to a single collector substation where the connection to the high-voltage transmission is established through a step up transformer. With a large number of wind generators per feeder, large inrush current will flow due to simultaneous transformer energization which can cause high voltage sag at the point of common coupling. Wind farms are generally located in unpopulated remote areas where no access to strong network connection is feasible. It is common to have the PCC on a relatively weak location on the sub-transmission/distribution network. In order to meet interconnection standards requirements, the amount of voltage sag due to the energization of a number of transformers needs to be evaluated. This paper presented an effective solution to the mitigation of inrush currents and associated voltage sag for wind farm applications. The paper presented a diagram of a typical configuration of a wind farm electrical distribution system and also described the analytical methodologies for the evaluation of inrush current level together with simulation results. A simplified analysis and sizing criteria for the associated neutral resistor size was presented. It was concluded that the scheme could significantly reduce inrush current level when a large number of transformers are simultaneously energized. The presented application eliminates the need to sectionalize feeders, thereby simplifying them for the energization process. 6 refs., 5 figs.

  14. Mesoscale to microscale wind farm flow modeling and evaluation

    DEFF Research Database (Denmark)

    Sanz Rodrigo, Javier; Chávez Arroyo, Roberto Aurelio; Moriarty, Patrick

    2017-01-01

    The increasing size of wind turbines, with rotors already spanning more than 150m diameter and hub heights above 100m, requires proper modeling of the atmospheric boundary layer (ABL) from the surface to the free atmosphere. Furthermore, large wind farm arrays create their own boundary layer stru...

  15. On the Impact of Wind Farms on a Convective Atmospheric Boundary Layer

    Science.gov (United States)

    Lu, Hao; Porté-Agel, Fernando

    2015-10-01

    With the rapid growth in the number of wind turbines installed worldwide, a demand exists for a clear understanding of how wind farms modify land-atmosphere exchanges. Here, we conduct three-dimensional large-eddy simulations to investigate the impact of wind farms on a convective atmospheric boundary layer. Surface temperature and heat flux are determined using a surface thermal energy balance approach, coupled with the solution of a three-dimensional heat equation in the soil. We study several cases of aligned and staggered wind farms with different streamwise and spanwise spacings. The farms consist of Siemens SWT-2.3-93 wind turbines. Results reveal that, in the presence of wind turbines, the stability of the atmospheric boundary layer is modified, the boundary-layer height is increased, and the magnitude of the surface heat flux is slightly reduced. Results also show an increase in land-surface temperature, a slight reduction in the vertically-integrated temperature, and a heterogeneous spatial distribution of the surface heat flux.

  16. Multicriteria GIS modeling of wind and solar farms in Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Jason R. [Metropolitan State College of Denver, Department of Earth and Atmospheric Sciences, CB 22 P.O. Box 173362-22, Denver, CO 80217-3362 (United States)

    2010-10-15

    The majority of electricity and heat in Colorado comes from coal and natural gas; however, renewable energy sources will play an integral role in the state's energy future. Colorado is the 11th windiest state and has more than 250 sunny days per year. The objectives of this research are to: 1) determine which landcover classes are affiliated with high wind and solar potential; and 2) identify areas that are suitable for wind and solar farms using multicriteria GIS modelling techniques. Renewable potential (NREL wind speed measurements at 50 m above the ground and NREL annual insolation data), landcover, population density, federal lands, and distance to roads, transmission lines, and cities were reclassified according to their suitability. Each was assigned weights based on their relative importance to one another. Superb wind classes are located in high alpine areas. Unfortunately, these areas are not suitable for large-scale wind farm development due to their inaccessibility and location within a sensitive ecosystem. Federal lands have low wind potential. According to the GIS model, ideal areas for wind farm development are located in northeastern Colorado. About 41 850 km{sup 2} of the state has model scores that are in the 90-100% range. Although annual solar radiation varies slightly, inter-mountain areas receive the most insolation. As far as federal lands, Indian reservations have the greatest solar input. The GIS model indicates that ideal areas for solar development are located in northwestern Colorado and east of Denver. Only 191 km{sup 2} of the state had model scores that were in the 90-100% range. These results suggest that the variables used in this analysis have more of an effect at eliminating non-suitable areas for large-scale solar farms; a greater area exists for suitable wind farms. However, given the statewide high insolation values with minimal variance, solar projects may be better suited for small-scale residential or commercial

  17. Wake losses optimization of offshore wind farms with moveable floating wind turbines

    International Nuclear Information System (INIS)

    Rodrigues, S.F.; Teixeira Pinto, R.; Soleimanzadeh, M.; Bosman, Peter A.N.; Bauer, P.

    2015-01-01

    Highlights: • We present a layout optimization framework for wind farms with moveable turbines. • Using moveable wind turbines in optimized layouts maximizes energy production. • Turbine and wind farm designers should cooperate to optimize offshore wind projects. - Abstract: In the future, floating wind turbines could be used to harvest energy in deep offshore areas where higher wind mean speeds are observed. Currently, several floating turbine concepts are being designed and tested in small scale projects; in particular, one concept allows the turbine to move after installation. This article presents a novel layout optimization framework for wind farms composed of moveable floating turbines. The proposed framework uses an evolutionary optimization strategy in a nested configuration which simultaneously optimizes the anchoring locations and the wind turbine position within the mooring lines for each individual wind direction. The results show that maximum energy production is obtained when moveable wind turbines are deployed in an optimized layout. In conclusion, the framework represents a new design optimization tool for future offshore wind farms composed of moveable floating turbines

  18. International wind farm markets: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Rackstraw, K. [American Wind Energy Association, Washington, DC (United States)

    1996-12-31

    More wind energy capacity was installed in 1995 than in any previous year. Two markets, Germany and India, accounted for nearly two-thirds of those installations, while the largest single market in the world historically, the US, ground nearly to a halt. Market supports in Germany and India, however, are vulnerable to political forces largely beyond the control of the wind industry. This paper examines the growth of international wind farm markets worldwide and notes that future markets will be more broadly based, leaving the industry less vulnerable to political changes. The paper also concludes that an additional 18,500 MW could be installed by the year 2005 even without assuming a dire ecological scenario that would create environmental drivers to accelerate wind market growth. 4 figs.

  19. Numerical simulations of flow fields through conventionally controlled wind turbines and wind farms

    International Nuclear Information System (INIS)

    Yilmaz, Ali Emre; Meyers, Johan

    2014-01-01

    In the current study, an Actuator-Line Model (ALM) is implemented in our in-house pseudo-spectral LES solver SP-WIND, including a turbine controller. Below rated wind speed, turbines are controlled by a standard-torque-controller aiming at maximum power extraction from the wind. Above rated wind speed, the extracted power is limited by a blade pitch controller which is based on a proportional-integral type control algorithm. This model is used to perform a series of single turbine and wind farm simulations using the NREL 5MW turbine. First of all, we focus on below-rated wind speed, and investigate the effect of the farm layout on the controller calibration curves. These calibration curves are expressed in terms of nondimensional torque and rotational speed, using the mean turbine-disk velocity as reference. We show that this normalization leads to calibration curves that are independent of wind speed, but the calibration curves do depend on the farm layout, in particular for tightly spaced farms. Compared to turbines in a lone-standing set-up, turbines in a farm experience a different wind distribution over the rotor due to the farm boundary-layer interaction. We demonstrate this for fully developed wind-farm boundary layers with aligned turbine arrangements at different spacings (5D, 7D, 9D). Further we also compare calibration curves obtained from full farm simulations with calibration curves that can be obtained at a much lower cost using a minimal flow unit

  20. IEA-Task 31 WAKEBENCH: Towards a protocol for wind farm flow model evaluation. Part 2: Wind farm wake models

    Science.gov (United States)

    Moriarty, Patrick; Sanz Rodrigo, Javier; Gancarski, Pawel; Chuchfield, Matthew; Naughton, Jonathan W.; Hansen, Kurt S.; Machefaux, Ewan; Maguire, Eoghan; Castellani, Francesco; Terzi, Ludovico; Breton, Simon-Philippe; Ueda, Yuko

    2014-06-01

    Researchers within the International Energy Agency (IEA) Task 31: Wakebench have created a framework for the evaluation of wind farm flow models operating at the microscale level. The framework consists of a model evaluation protocol integrated with a web-based portal for model benchmarking (www.windbench.net). This paper provides an overview of the building-block validation approach applied to wind farm wake models, including best practices for the benchmarking and data processing procedures for validation datasets from wind farm SCADA and meteorological databases. A hierarchy of test cases has been proposed for wake model evaluation, from similarity theory of the axisymmetric wake and idealized infinite wind farm, to single-wake wind tunnel (UMN-EPFL) and field experiments (Sexbierum), to wind farm arrays in offshore (Horns Rev, Lillgrund) and complex terrain conditions (San Gregorio). A summary of results from the axisymmetric wake, Sexbierum, Horns Rev and Lillgrund benchmarks are used to discuss the state-of-the-art of wake model validation and highlight the most relevant issues for future development.

  1. IEA-Task 31 WAKEBENCH: Towards a protocol for wind farm flow model evaluation. Part 2: Wind farm wake models

    International Nuclear Information System (INIS)

    Moriarty, Patrick; Rodrigo, Javier Sanz; Gancarski, Pawel; Chuchfield, Matthew; Naughton, Jonathan W; Hansen, Kurt S; Machefaux, Ewan; Maguire, Eoghan; Castellani, Francesco; Terzi, Ludovico; Breton, Simon-Philippe; Ueda, Yuko

    2014-01-01

    Researchers within the International Energy Agency (IEA) Task 31: Wakebench have created a framework for the evaluation of wind farm flow models operating at the microscale level. The framework consists of a model evaluation protocol integrated with a web-based portal for model benchmarking (www.windbench.net). This paper provides an overview of the building-block validation approach applied to wind farm wake models, including best practices for the benchmarking and data processing procedures for validation datasets from wind farm SCADA and meteorological databases. A hierarchy of test cases has been proposed for wake model evaluation, from similarity theory of the axisymmetric wake and idealized infinite wind farm, to single-wake wind tunnel (UMN-EPFL) and field experiments (Sexbierum), to wind farm arrays in offshore (Horns Rev, Lillgrund) and complex terrain conditions (San Gregorio). A summary of results from the axisymmetric wake, Sexbierum, Horns Rev and Lillgrund benchmarks are used to discuss the state-of-the-art of wake model validation and highlight the most relevant issues for future development

  2. Differential recovery of habitat use by birds after wind farm installation: A multi-year comparison

    International Nuclear Information System (INIS)

    Farfán, M.A.; Duarte, J.; Real, R.; Muñoz, A.R.; Fa, J.E.; Vargas, J.M.

    2017-01-01

    Onshore wind farms remain one of the most widely used technologies for the production of renewable energy. These are known to affect birds through disturbance or collision. Most research focus on the impact of wind farms on raptors or other large bird species, especially those of conservation concern. However, limited information exists on the effect of wind farms on small birds. Recovery of large versus small bird populations impacted by wind farms is also largely unstudied. A reason for this is the lack of long-term datasets based on standardized, systematic assessments. We monitored birds in the vicinity of a wind farm in an upland habitat in southern Spain (Malaga province), immediately after installation and 6.5 years post-construction. During both study periods, we observed 11 raptor and 38 non-raptor species (including 30 passerines). We found differences in recovery rates between raptors and non-raptors. Raptors showed an upturn in numbers but non-raptor abundance fell significantly. Greater attention should be paid to the recovery of wildlife after initial impact assessments than at present. This study confirms that regulatory authorities and developers should consider the likely impacts of wind farms on small bird populations. Mitigation measures focused particularly on non-raptor species should be considered and implemented as a means to reduce these negative effects.

  3. Differential recovery of habitat use by birds after wind farm installation: A multi-year comparison

    Energy Technology Data Exchange (ETDEWEB)

    Farfán, M.A., E-mail: mafarfanaguilar@hotmail.com [Biogea Consultores, Calle Navarro Ledesma 243, Portal 4, 3° C, 29010, Málaga (Spain); Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Málaga (Spain); Duarte, J., E-mail: jddofitecma@gmail.com [Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Málaga (Spain); Ofitecma, Calle Colombia 5, 29400 Ronda, Málaga (Spain); Real, R. [Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Málaga (Spain); Muñoz, A.R., E-mail: roman@uma.es [Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Málaga (Spain); Departamento de Botànica, Facultad de Farmacia, Universidad de Valencia, Avda. Vicente Andrés Estellés s/n, Burjassot, Valencia (Spain); Fa, J.E., E-mail: jfa949@gmail.com [Division of Biology and Conservation Ecology, School of Science and the Environment, Manchester Metropolitan University, Manchester M1 5GD (United Kingdom); Vargas, J.M. [Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Málaga (Spain)

    2017-05-15

    Onshore wind farms remain one of the most widely used technologies for the production of renewable energy. These are known to affect birds through disturbance or collision. Most research focus on the impact of wind farms on raptors or other large bird species, especially those of conservation concern. However, limited information exists on the effect of wind farms on small birds. Recovery of large versus small bird populations impacted by wind farms is also largely unstudied. A reason for this is the lack of long-term datasets based on standardized, systematic assessments. We monitored birds in the vicinity of a wind farm in an upland habitat in southern Spain (Malaga province), immediately after installation and 6.5 years post-construction. During both study periods, we observed 11 raptor and 38 non-raptor species (including 30 passerines). We found differences in recovery rates between raptors and non-raptors. Raptors showed an upturn in numbers but non-raptor abundance fell significantly. Greater attention should be paid to the recovery of wildlife after initial impact assessments than at present. This study confirms that regulatory authorities and developers should consider the likely impacts of wind farms on small bird populations. Mitigation measures focused particularly on non-raptor species should be considered and implemented as a means to reduce these negative effects.

  4. Wind-Farm Parametrisations in Mesoscale Models

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    2013-01-01

    In this paper we compare three wind-farm parametrisations for mesoscale models against measurement data from the Horns Rev I offshore wind-farm. The parametrisations vary from a simple rotor drag method, to more sophisticated models. Additional to (4) we investigated the horizontal resolution dep...

  5. Large wind farms in the electric power systems. Voltage quality and power dynamics. Final report; Store vindmoelleparker i elsystemet. Spaendingskvalitet og effektdynamik. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-12-01

    The aim of the project has partly been to compare practical measurements with theoretical calculations in order to make quantitative evaluations of the consequences for the power system when large offshore wind farms are connected and partly to develop a regulation algorithm for control of offshore wind farm's power production meeting the demands of the connection conditions. A comparison between calculated flicker emissions and measured flicker emissions has shown that the IEC standard for calculation of flicker emissions from wind farms is conservative as the counterbalancing is underestimated. The calculated flicker emissions are approx. twice as big as the measured flicker emissions. A comparison between theoretical simulations of grid faults and measurement tests has shown satisfying correspondence. This has validated the newly developed theoretical models of offshore wind turbines for simulation of stability conditions in the power system. The validation has been an important element during evaluations of offshore wind turbines' effect on the operating stability of the power system and hereby the reliability of supply. A failsafe regulation algorithm for control of offshore wind farms maximum (instantaneous)production has been developed. The algorithm has been implemented and tested in practice and has proven to work satisfactory. (BA)

  6. Pre-feasibility study of 80mw onshore wind farm

    International Nuclear Information System (INIS)

    Almas, M.S.

    2014-01-01

    This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa) province previously known as NWFP (North West Frontier) Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology and Climatology (University of the Punjab) to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis) is presented and the feasibility of the project from the investor's point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years. (author)

  7. Wind Farm Decentralized Dynamic Modeling With Parameters

    DEFF Research Database (Denmark)

    Soltani, Mohsen; Shakeri, Sayyed Mojtaba; Grunnet, Jacob Deleuran

    2010-01-01

    Development of dynamic wind flow models for wind farms is part of the research in European research FP7 project AEOLUS. The objective of this report is to provide decentralized dynamic wind flow models with parameters. The report presents a structure for decentralized flow models with inputs from...... local models. The results of this report are especially useful, but not limited, to design a decentralized wind farm controller, since in centralized controller design one can also use the model and update it in a central computing node.......Development of dynamic wind flow models for wind farms is part of the research in European research FP7 project AEOLUS. The objective of this report is to provide decentralized dynamic wind flow models with parameters. The report presents a structure for decentralized flow models with inputs from...

  8. Offshore wind farm Bockstigen - installation and operation experience

    Energy Technology Data Exchange (ETDEWEB)

    Lange, B [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark); Aagaard, E; Andersen, P E; Moeller, A [Wind World af 1997 A/S, Noerresundby (Denmark); Niklasson, S; Wickman, A [Vindkompaniet, Degerhamn (Sweden)

    1999-03-01

    The first Swedish offshore wind farm Bockstigen is operating since March 1998 near the coast of Gotland. It was built as a demonstration project by the Swedish wind farm developer Vindkompaniet, the Danish wind turbine manufacturer Wind World and the British offshore construction company Seacore and partly funded under the EU-THERMIE program. Bockstigen is the fourth offshore wind farm world-wide. While at previous wind farms the main emphasis laid on the demonstration of the technical feasibility of offshore wind energy utilisation, Bockstigen was aimed at demonstrating its economic viability. A number of innovative concepts have been employed: Drilled monopile foundations were used to save costs. A new construction method has been applied making use of a jack-up barge. A new control system for the turbines and the whole wind farm was developed, which controls the maximum power output, the flicker and the reactive power consumption depending on online measurements of the actual grid state. These new developments have been implemented successfully. A substantial cost reduction compared to previous offshore projects could be achieved. (au)

  9. The influence of reactive current on wind farm LVRT behavior

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qing; Zhang, Mei; He, Jing; Qin, Shi-yao [China Electric Power Research Institute, Beijing (China)

    2012-07-01

    The Low voltage ride through (LVRT) capability of the whole wind farm is required in Chinese grid code published in 2011. In order to analyze the influence of reactive current on wind farm during grid fault, a 100 MW wind farm was simulated with the wind turbines which have been tested. Based on the validated wind turbine model, the wind farm was detailed modelled in DigSILENT/PowerFactory. The model of wind turbines, transformers, feeders, main transformers, static var compensator, and transmission lines was considered in the simulation. Under the weak and strong grid conditions, the wind farm was simulated with different wind turbine reactive current behavior during grid fault, respectively. The voltage distribution, active and reactive power transient behavior at the point of interconnection was analyzed. The results show that wind farm LVRT behavior is related to reactive current and LVRT capability of wind turbine, wind farm electrical structure and grid conditions. And it is very important for wind turbine to have a flexible dynamic reactive current control capability. (orig.)

  10. Tuno Knob Offshore Wind Farm

    International Nuclear Information System (INIS)

    Madsen, P.S.

    1996-01-01

    In 1995 Midtkraft Power Company built Denmark's second offshore wind farm as a demonstration project. The project purpose is first of all to investigate the environmental aspects of offshore wind energy. The two primary objects are to study the impact on bird life and to test different methods for predicting the visual effect. The wind farm consists of 10 pitch-regulated Vestas V39 500 kW wind turbines placed on box caisson foundations in a shallow water area 6 km east of Jutland. The project has been implemented successfully under a very narrow time schedule, and during the first 6 months in operation, the production has been approx. 30% higher than expected. (author)

  11. Pre-Feasibility Study of 80MW Onshore Wind Farm

    Directory of Open Access Journals (Sweden)

    Muhammad Shoaib Almas

    2014-10-01

    Full Text Available This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa province previously known as NWFP (North West Frontier Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology & Climatology (University of the Punjab to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis is presented and the feasibility of the project from the investor?s point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years

  12. Centralised control of wind farm with doubly-fed induction generators

    DEFF Research Database (Denmark)

    Hansen, A.D.; Sørensen, Poul Ejnar; Iov, F.

    2005-01-01

    This paper describes the development of an advanced wind farm controller for a wind farm made-up exclusively of doubly-fed generators. The overall aim of such controller is to enable the wind farms to behave as active controllable components in the power system. The attention is mainly drawn...... to the ability of the wind farm control strategy to regulate the wind farm power production to the reference power ordered by the system operators. The performance of the control strategy is assessed and discussed by means of normal operation simulations of a grid connected wind farm....

  13. Turbulent Flow Inside and Above a Wind Farm: A Wind-Tunnel Study

    Directory of Open Access Journals (Sweden)

    Leonardo P. Chamorro

    2011-11-01

    Full Text Available Wind-tunnel experiments were carried out to better understand boundary layer effects on the flow pattern inside and above a model wind farm under thermally neutral conditions. Cross-wire anemometry was used to characterize the turbulent flow structure at different locations around a 10 by 3 array of model wind turbines aligned with the mean flow and arranged in two different layouts (inter-turbine separation of 5 and 7 rotor diameters in the direction of the mean flow by 4 rotor diameters in its span. Results suggest that the turbulent flow can be characterized in two broad regions. The first, located below the turbine top tip height, has a direct effect on the performance of the turbines. In that region, the turbulent flow statistics appear to reach equilibrium as close as the third to fourth row of wind turbines for both layouts. In the second region, located right above the first one, the flow adjusts slowly. There, two layers can be identified: an internal boundary layer where the flow is affected by both the incoming wind and the wind turbines, and an equilibrium layer, where the flow is fully adjusted to the wind farm. An adjusted logarithmic velocity distribution is observed in the equilibrium layer starting from the sixth row of wind turbines. The effective surface roughness length induced by the wind farm is found to be higher than that predicted by some existing models. Momentum recovery and turbulence intensity are shown to be affected by the wind farm layout. Power spectra show that the signature of the tip vortices, in both streamwise and vertical velocity components, is highly affected by both the relative location in the wind farm and the wind farm layout.

  14. Integration of large wind farms into weak power grids. Emphasis on the Ethiopian interconnected system (ICS)

    Energy Technology Data Exchange (ETDEWEB)

    Bantyirga Gessesse, Belachew

    2013-07-18

    The impact of increased wind power on the steady state and dynamic behavior of the Ethiopian power system is the main focus of this thesis. The integration of wind power to the existing grid with conventional generators introduces new set of challenges regarding system security and operational planning, the main cause of the difference arising from the uncertainty of the primary source of energy and the response time following a disturbance. For incorporating wind turbine models into the overall dynamic model of the system and investigating the effect of wind on the dynamic behavior of the wind first models of wind turbine components were put together by reviewing the current state of the art in wind turbine modeling and control concepts. The theoretical insight thus gained was applied to the Ethiopian power system as a case study. Since the models of the installed turbines were either not available or incomplete, an alternative modeling approach based on generic models was adopted. The generic model, in addition to obviating the need for technology or manufacturer specific models, reduces the complexity the dynamic model. Using this procedure, generic dynamic models for wind farm in the system were developed. The capability of dynamic models to reproduce the dynamic response of the system has been verified by comparing simulation results obtained with a detailed and generic wind farm model. It could be shown that the generic wind turbine model is simple, but accurate enough to represent any wind turbine types or entire wind farms for power system stability analysis. The next task was the study of the effect of increased wind power level on the general behavior of the Ethiopian system. It is observed that overall the impact of wind turbines on the operational indices of the system was -as could be expected- more pronounced in the vicinity of the wind farm. But the power angle oscillation following a disturbance was observed across the whole system. Further, as a

  15. CWEX: Crop/wind-energy experiment: Observations of surface-layer, boundary-layer and mesoscale interactions with a wind farm

    Science.gov (United States)

    Large wind turbines perturb mean and turbulent wind characteristics, which modify fluxes between the vegetated surface and the lower boundary layer. While simulations have suggested that wind farms could create significant changes in surface fluxes of heat, momentum, moisture, and CO2 over hundreds ...

  16. Crop/Wind-energy Experiment (CWEX): Observations of surface-layer, boundary-layer and mesoscale interactions with a wind farm

    Science.gov (United States)

    Perturbations of mean and turbulent wind characteristics by large wind turbines modify fluxes between the vegetated surface and the lower boundary layer. While simulations have suggested that wind farms could significantly change surface fluxes of heat, momentum, moisture, and CO2 over hundreds of s...

  17. NORCOWE Reference Wind Farm

    DEFF Research Database (Denmark)

    Bak, Thomas; Graham, Angus

    2015-01-01

    Offshore wind farms are complex systems, influenced by both the environment (e.g. wind, waves, current and seabed) and the design characteristics of the equipment available for installation (e.g. turbine type, foundations, cabling and distance to shore). These aspects govern the capital and opera...

  18. Modelling of offshore wind turbine wakes with the wind farm program FLaP

    DEFF Research Database (Denmark)

    Lange, B.; Waldl, H.P.; Guerrero, A.G.

    2003-01-01

    The wind farm layout program FLaP estimates the wind speed at any point in a wind farm and the power output of the turbines. The ambient flow conditions and the properties of the turbines and the farm are used as input. The core of the program is an axisymmetric wake model describing the wake...

  19. Environmental screening report : Harrow Wind Farm

    International Nuclear Information System (INIS)

    2008-04-01

    AIM PowerGen Corporation is proposing to develop a wind energy project located on the northern shores of Lake Erie, Ontario called the Harrow Wind Farm. The wind energy project would consist of 24 wind turbines having a total capacity of 39.6 megawatts and comprise four small projects of six wind turbines each to be submitted to the standard offer program. The purpose of the project is to supply clean energy to the Ontario energy system using state-of-the-art wind energy technology. This report presented an environmental screening of the Harrow Wind Farm, as required by the Canadian Environmental Assessment Act and the Ontario Environmental Assessment Act. The report provided a detailed description of the Harrow Wind Farm location, optimization process and schedule as well as a detailed characterization of the natural and socio-economic environment. The report also provided a description of the regulatory agencies, as well as public and First Nations consultation activities. The effects on natural and socio-economic components were evaluated and an accidents and malfunction plan was also presented. Last, the report included a discussion of the effects of the environment on the Harrow Wind Farm; a summary of mitigation, impact management, and monitoring commitments of AIM PowerGen; and an overview of environmental advantages and disadvantages. It was concluded that the project design has benefited from several consultations with local authorities, lot owners and local residents, as well as federal and provincial agencies to ensure that environmental and social impacts are minimized while maximizing energy generation. refs., tabs., figs

  20. Offshore Wind Farm Cable Connection Configuration Optimization using Dynamic Minimum Spanning Tree Algorithm

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Zhe

    2015-01-01

    Anew approach, Dynamic Minimal Spanning Tree (DMST) algorithm, whichisbased on the MST algorithm isproposed in this paper to optimizethe cable connectionlayout for large scale offshore wind farm collection system. The current carrying capacity of the cable is considered as the main constraint....... It is amore economicalway for cable connection configurationdesignof offshore wind farm collection system....

  1. Challenges in simulating coastal effects on an offshore wind farm

    DEFF Research Database (Denmark)

    van der Laan, Paul; Peña, Alfredo; Volker, Patrick

    2017-01-01

    The effect of a coastline on an offshore wind farm is investigated with a Reynolds-averaged Navier-Stokes (RANS) model. The trends of the RANS model compare relatively well with results from a mesoscale model and measurements of wind turbine power. In addition, challenges of modeling a large domain...

  2. Estimating the true energy value of a wind farm

    International Nuclear Information System (INIS)

    Bass, J.

    1995-01-01

    To assess the true energy yield of a wind farm taking into account real-world effects such as control losses in individual turbines, losses in the distribution network and wake and topographic effects, this report from the Energy Technology Support Unit, has developed a more appropriate methodology for making economic assessments of wind farm projects. Simulations of wind turbines are used to enable control losses to be quantified, and long term performance data from wind turbines in operational United Kingdom wind farms adds to the accuracy of assessment. A model has also been used to estimate performance of a power distribution system for a wind farm, to enable losses associated with wind turbine, wind speed and various distribution layouts to be predicted. Data on wake effects are drawn from a separate study. All these are drawn into an economic simulation model which predicts a wind farm's likely achievement of its target energy yield, thus demonstrating the risk factors involved. (UK)

  3. Wind farm models and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Iov, F.; Blaabjerg, F.; Donovan, M.H.

    2005-08-01

    This report describes models and control strategies for 3 different concepts of wind farms. Initially, the potential in improvement of grid integration, structural loads and energy production is investigated in a survey of opportunities. Then simulation models are described, including wind turbine models for a fixed speed wind turbine with active stall control and a variable speed wind turbine with doubly-fed induction generator. After that, the 3 wind farm concepts and control strategies are described. The 3 concepts are AC connected doubly fed turbines, AC connected active stall turbines and DC connected active stall turbines. Finally, some simulation examples and conclusions are presented. (au)

  4. Blyth Harbour wind farm - operational aspects

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This report is the last in a series of seven on various aspects of the monitoring and evaluation of the Blyth Northumberland off-shore wind farm project. The wind farm was the first to be built in the UK: it consists of two 2MW wind turbines about 1 km from the coast in water of depth 5-6 m. The subject of this report is the actual performance of the wind turbine relative to predicted performance. The study showed up the problems of operating a wind farm at sea and the need for comprehensive testing before installation. The problems encountered were numerous but in no case major. A lightning strike destroyed a turbine blade (for which no replacement was readily available) and there was a cable fault caused by installation deficiencies. Better planning could have avoided lengthy shutdowns. The report covers the availability of the turbines and performance of ancillary equipment.

  5. Structural Flexibility of Large Direct Drive Generators for Wind Turbines

    NARCIS (Netherlands)

    Shrestha, G.

    2013-01-01

    The trend in wind energy is towards large offshore wind farms. This trend has led to the demand for high reliability and large single unit wind turbines. Different energy conversion topologies such as multiple stage geared generators, single stage geared generators and gearless (direct drive)

  6. The comprehensive atlas of wind farms in France

    International Nuclear Information System (INIS)

    Le Jannic, N.; Vincent, C.

    2014-01-01

    This article reports the 1075 wind farms installed or planned on the French territory. The figures were collected during the first semester of 2014. The total installed capacity is 8678.9 MW and the planned farms represent a future capacity of 4288.1 MW, the planned farms will enter into operation during the next 3 years. For each farm the following data has been reported: city, operator, capacity and number of wind turbines, manufacturer and date of entry into operation. The wind farms are classified according to the department in which they are located. (A.C.)

  7. Different Shades of Green: A Case Study of Support for Wind Farms in the Rural Midwest

    Science.gov (United States)

    Mulvaney, Kate K.; Woodson, Patrick; Prokopy, Linda Stalker

    2013-05-01

    Benton County, in north-central Indiana, USA has successfully sited more than 500 turbines. To understand Benton County's acceptance of wind farms, a holistic case study was conducted that included a document review, a survey of local residents and interviews with key stakeholders. Survey questionnaires were sent to 750 residents asking questions about attitudes toward the wind farms, perceived benefits and impacts from the wind farms, environmental attitudes, and demographic information. Key stakeholders were also interviewed for a deeper understanding of the historical timeline and community acceptance of the wind farm development. While there is limited opposition to the turbines, on the whole the community presents a front of acceptance. Financial, rather than environmental, benefits are the main reason for the acceptance. Although significant in other case studies, transparency and participation do not play a large role in Benton County's acceptance. Most residents are not concerned with either visual impacts or noise from the wind turbines. More concrete benefits to the community, such as reduced energy bills for county residents, could help to extend acceptance even further within the community. Although there are concerns about the acceptance of wind farms and the impacts of those farms on local residents in both peer-reviewed literature and popular media, we found little evidence of those concerns in Benton County. Instead, we found Benton County to be a community largely accepting of wind farms.

  8. Wind farms on undegraded peatlands are unlikely to reduce future carbon emissions

    International Nuclear Information System (INIS)

    Smith, Jo; Nayak, Dali Rani; Smith, Pete

    2014-01-01

    Onshore wind energy is a key component of the renewable energies used by governments to reduce carbon emissions from electricity production, but will carbon emissions be reduced when wind farms are located on carbon-rich peatands? Wind farms are often located in uplands because most are of low agricultural value, are distant from residential areas, and are windy. Many UK uplands are peatlands, with layers of accumulated peat that represent a large stock of soil carbon. When peatlands are drained for construction there is a higher risk of net carbon loss than for mineral soils. Previous work suggests that wind farms sited on peatlands can reduce net carbon emissions if strictly managed for maximum retention of carbon. Here we show that, whereas in 2010, most sites had potential to provide net carbon savings, by 2040 most sites will not reduce carbon emissions even with careful management. This is due to projected changes in the proportion of fossil fuels used to generate electricity. The results suggest future policy should avoid constructing wind farms on undegraded peatlands unless drainage of peat is minimal and the volume excavated in foundations can be significantly reduced compared to energy output. - Highlights: • Future wind farms located on undegraded peats will not reduce carbon emissions. • This is due to projected changes in fossil fuels used to generate electricity. • Future policy should avoid constructing wind farms on undegraded peats

  9. An assessment of the potential for business use of wind turbines on farms in Scotland

    International Nuclear Information System (INIS)

    Hunter, A.G.M.; Graham, R.; Morgan, O.W.

    1998-01-01

    High wind speeds on farms in Scotland, coupled with on-site demands for electricity, suggest there is potential for installing single wind turbines on these farms to generate electricity. The benefit of avoided costs for on-site supplies will help to lower the effective generating costs of surplus electricity for sale. Using a sensitivity analysis to examine a range of parameter settings for financial costs, wind speeds, and farm grants, it is shown that a turbine can be viable on a farm. The key to viability is to have correct and accurate matching between turbine and farm business, there being a place for both large turbines and small turbines under separate circumstances. There are scenarios where a wind turbine is viable on half the farms in Scotland. (Author)

  10. Optimized Power Dispatch Strategy for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Zhang, Baohua

    2016-01-01

    which are related to electrical system topology. This paper proposed an optimized power dispatch strategy (OPD) for minimizing the levelized production cost (LPC) of a wind farm. Particle swarm optimization (PSO) is employed to obtain final solution for the optimization problem. Both regular shape......Maximizing the power production of offshore wind farms using proper control strategy has become an important issue for wind farm operators. However, the power transmitted to the onshore substation (OS) is not only related to the power production of each wind turbine (WT) but also the power losses...... and irregular shape wind farm are chosen for the case study. The proposed dispatch strategy is compared with two other control strategies. The simulation results show the effectiveness of the proposed strategy....

  11. The complete list of wind farms in France

    International Nuclear Information System (INIS)

    Le jannic, N.

    2013-01-01

    This list takes into account all the wind farms present or being constructed in France at the end of may 2013. The installed capacity reached 7913.4 MW while the projected capacity represents 3925.1 MW. 982 wind farms are reported in this document. For each wind farm the following pieces of information are reported: the name of the operator, the power output, the number of wind turbines, the name of the turbine manufacturer, and the date of commissioning. (A.C.)

  12. Analysis of High Frequency Resonance in DFIG-based Offshore Wind Farm via Long Transmission Cable

    DEFF Research Database (Denmark)

    Song, Yipeng; Ebrahimzadeh, Esmaeil; Blaabjerg, Frede

    2018-01-01

    During the past two decades, the Doubly Fed Induction Generator (DFIG) based wind farm has been under rapid growth, and the increasing wind power penetration has been seen. Practically, these wind farms are connected to the three-phase AC grid through long transmission cable which can be modelled...... as several II units. The impedance of this cable cannot be neglected and requires careful investigation due to its long distance. As a result, the impedance interaction between the DFIG based wind farm and the long cable is inevitable, and may produce High Frequency Resonance (HFR) in the wind farm....... This paper discusses the HFR of the large scale DFIG based wind farm connected to the long cable. Several influencing factors, including 1) the length of the cable, 2) the output active power and 3) the rotor speed, are investigated. Simulation validations using MATLAB / Simulink have been conducted...

  13. Accurate wind farm development and operation. Advanced wake modelling

    Energy Technology Data Exchange (ETDEWEB)

    Brand, A.; Bot, E.; Ozdemir, H. [ECN Unit Wind Energy, P.O. Box 1, NL 1755 ZG Petten (Netherlands); Steinfeld, G.; Drueke, S.; Schmidt, M. [ForWind, Center for Wind Energy Research, Carl von Ossietzky Universitaet Oldenburg, D-26129 Oldenburg (Germany); Mittelmeier, N. REpower Systems SE, D-22297 Hamburg (Germany))

    2013-11-15

    The ability is demonstrated to calculate wind farm wakes on the basis of ambient conditions that were calculated with an atmospheric model. Specifically, comparisons are described between predicted and observed ambient conditions, and between power predictions from three wind farm wake models and power measurements, for a single and a double wake situation. The comparisons are based on performance indicators and test criteria, with the objective to determine the percentage of predictions that fall within a given range about the observed value. The Alpha Ventus site is considered, which consists of a wind farm with the same name and the met mast FINO1. Data from the 6 REpower wind turbines and the FINO1 met mast were employed. The atmospheric model WRF predicted the ambient conditions at the location and the measurement heights of the FINO1 mast. May the predictability of the wind speed and the wind direction be reasonable if sufficiently sized tolerances are employed, it is fairly impossible to predict the ambient turbulence intensity and vertical shear. Three wind farm wake models predicted the individual turbine powers: FLaP-Jensen and FLaP-Ainslie from ForWind Oldenburg, and FarmFlow from ECN. The reliabilities of the FLaP-Ainslie and the FarmFlow wind farm wake models are of equal order, and higher than FLaP-Jensen. Any difference between the predictions from these models is most clear in the double wake situation. Here FarmFlow slightly outperforms FLaP-Ainslie.

  14. Analysis of losses within SMES system for compensating output fluctuation of wind power farm

    Energy Technology Data Exchange (ETDEWEB)

    Park, S. I.; Kim, J. H.; Le, T. D.; Lee, D. H.; Kim, H. M. [Jeju National University, Jeju (Korea, Republic of); Yoon, Y. S. [Dept. of Electrical Engineering, Shin Ansan University, Ansan (Korea, Republic of); Yoon, K. Y. [Dept. of lectrical and Electronic Engineering, Yonsei University, Seoul (Korea, Republic of)

    2014-12-15

    Output fluctuation which is generated in wind power farm can hinder stability of total power system. The electric energy storage (EES) reduces unstable output, and superconducting magnetic energy storage (SMES) of various EESs has the proper performance for output compensation of wind power farm since it charges and discharges large scale power quickly with high efficiency. However, because of the change of current within SMES, the electromagnetic losses occur in the process of output compensation. In this paper, the thermal effect of the losses that occur in SMES system while compensating in wind power farm is analyzed. The output analysis of wind power farm is processed by numerical analysis, and the losses of SMES system is analyzed by 3D finite element analysis (FEA) simulation tool.

  15. Analysis of losses within SMES system for compensating output fluctuation of wind power farm

    International Nuclear Information System (INIS)

    Park, S. I.; Kim, J. H.; Le, T. D.; Lee, D. H.; Kim, H. M.; Yoon, Y. S.; Yoon, K. Y.

    2014-01-01

    Output fluctuation which is generated in wind power farm can hinder stability of total power system. The electric energy storage (EES) reduces unstable output, and superconducting magnetic energy storage (SMES) of various EESs has the proper performance for output compensation of wind power farm since it charges and discharges large scale power quickly with high efficiency. However, because of the change of current within SMES, the electromagnetic losses occur in the process of output compensation. In this paper, the thermal effect of the losses that occur in SMES system while compensating in wind power farm is analyzed. The output analysis of wind power farm is processed by numerical analysis, and the losses of SMES system is analyzed by 3D finite element analysis (FEA) simulation tool.

  16. Adaptive neuro-fuzzy optimization of wind farm project net profit

    International Nuclear Information System (INIS)

    Shamshirband, Shahaboddin; Petković, Dalibor; Ćojbašić, Žarko; Nikolić, Vlastimir; Anuar, Nor Badrul; Mohd Shuib, Nor Liyana; Mat Kiah, Miss Laiha; Akib, Shatirah

    2014-01-01

    Highlights: • Analyzing of wind farm project investment. • Net present value (NPV) maximization of the wind farm project. • Adaptive neuro-fuzzy (ANFIS) optimization of the number of wind turbines to maximize NPV. • The impact of the variation in the wind farm parameters. • Adaptive neuro fuzzy application. - Abstract: A wind power plant which consists of a group of wind turbines at a specific location is also known as wind farm. To maximize the wind farm net profit, the number of turbines installed in the wind farm should be different in depend on wind farm project investment parameters. In this paper, in order to achieve the maximal net profit of a wind farm, an intelligent optimization scheme based on the adaptive neuro-fuzzy inference system (ANFIS) is applied. As the net profit measures, net present value (NPV) and interest rate of return (IRR) are used. The NPV and IRR are two of the most important criteria for project investment estimating. The general approach in determining the accept/reject/stay in different decision for a project via NPV and IRR is to treat the cash flows as known with certainty. However, even small deviations from the predetermined values may easily invalidate the decision. In the proposed model the ANFIS estimator adjusts the number of turbines installed in the wind farm, for operating at the highest net profit point. The performance of proposed optimizer is confirmed by simulation results. Some outstanding properties of this new estimator are online implementation capability, structural simplicity and its robustness against any changes in wind farm parameters. Based on the simulation results, the effectiveness of the proposed optimization strategy is verified

  17. Development of FAST.Farm: A New Multiphysics Engineering Tool for Wind-Farm Design and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, Jason; Annoni, Jennifer; Hayman, Greg; Jonkman, Bonnie; Purkayastha, Avi

    2017-01-09

    This paper presents the development of FAST.Farm, a new multiphysics tool applicable to engineering problems in research and industry involving wind farm performance and cost optimization that is needed to address the current underperformance, failures, and expenses plaguing the wind industry. Achieving wind cost-of-energy targets - which requires improvements in wind farm performance and reliability, together with reduced uncertainty and expenditures - has been eluded by the complicated nature of the wind farm design problem, especially the sophisticated interaction between atmospheric phenomena and wake dynamics and array effects. FAST.Farm aims to balance the need for accurate modeling of the relevant physics for predicting power performance and loads while maintaining low computational cost to support a highly iterative and probabilistic design process and system-wide optimization. FAST.Farm makes use of FAST to model the aero-hydro-servo-elastics of distinct turbines in the wind farm, and it is based on some of the principles of the Dynamic Wake Meandering (DWM) model, but avoids many of the limitations of existing DWM implementations.

  18. Deterministic and Stochastic Study of Wind Farm Harmonic Currents

    DEFF Research Database (Denmark)

    Sainz, Luis; Mesas, Juan Jose; Teodorescu, Remus

    2010-01-01

    Wind farm harmonic emissions are a well-known power quality problem, but little data based on actual wind farm measurements are available in literature. In this paper, harmonic emissions of an 18 MW wind farm are investigated using extensive measurements, and the deterministic and stochastic char...

  19. Proximity search heuristics for wind farm optimal layout

    DEFF Research Database (Denmark)

    Fischetti, Martina; Monaci, Michele

    2016-01-01

    A heuristic framework for turbine layout optimization in a wind farm is proposed that combines ad-hoc heuristics and mixed-integer linear programming. In our framework, large-scale mixed-integer programming models are used to iteratively refine the current best solution according to the recently...

  20. Monitoring of offshore wind farm using reliable communication

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, K.G.; Gajranib, K.; Bhargavac, A. [Rajasthan Technical Univ.. Dept. of Electrical Engineering, Kota (India)

    2012-07-01

    Due to rapid exhaustion of fossil fuels, new renewable technologies for electricity generation are insisted upon to meet the continuous growing demand of energy all across the globe. Wind energy as a green energy is a favorable option, among other available renewable sources. The offshore wind farm capacity is growing rapidly, but it's uncertain and intermittent nature offers great challenges to power system engineers. The cost of repair and down time, results into extensive damage and reduced profitability. This necessitates the requirement of fast and reliable communication network for the monitoring and controlling of the wind farm. In this paper, we have proposed the communication network for medium offshore wind farm (160MW). The wind farm consists of four clusters; each cluster comprises of 10 Wind Turbines (WTs), each of capacity 4MW. A WT can be represented by nine logical nodes according to IEC-61400-25 standard. The functions of logical nodes are modeled in terms of analogue /status/control information. The wind farm has been modeled in OPNET modeler and the performance of the communication network is evaluated in terms of End to End delay and packet drop, using Synchronous Optical NETwork (SONET) standard. (Author)

  1. Monitoring of offshore wind farm using reliable communication

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, K G; Gajranib, K; Bhargavac, A [Rajasthan Technical Univ. Dept. of Electrical Engineering, Kota (India)

    2012-07-01

    Due to rapid exhaustion of fossil fuels, new renewable technologies for electricity generation are insisted upon to meet the continuous growing demand of energy all across the globe. Wind energy as a green energy is a favorable option, among other available renewable sources. The offshore wind farm capacity is growing rapidly, but it's uncertain and intermittent nature offers great challenges to power system engineers. The cost of repair and down time, results into extensive damage and reduced profitability. This necessitates the requirement of fast and reliable communication network for the monitoring and controlling of the wind farm. In this paper, we have proposed the communication network for medium offshore wind farm (160MW). The wind farm consists of four clusters; each cluster comprises of 10 Wind Turbines (WTs), each of capacity 4MW. A WT can be represented by nine logical nodes according to IEC-61400-25 standard. The functions of logical nodes are modeled in terms of analogue /status/control information. The wind farm has been modeled in OPNET modeler and the performance of the communication network is evaluated in terms of End to End delay and packet drop, using Synchronous Optical NETwork (SONET) standard. (Author)

  2. Integrative modeling and novel particle swarm-based optimal design of wind farms

    Science.gov (United States)

    Chowdhury, Souma

    allowing simultaneous optimization of the type and the location of the turbines. Layout optimization (using UWFLO) of a hypothetical 25-turbine commercial-scale wind farm provides a remarkable 4.4% increase in capacity factor compared to a conventional array layout. A further 2% increase in capacity factor is accomplished when the types of turbines are also optimally selected. The scope of turbine selection and placement however depends on the land configuration and the nameplate capacity of the farm. Such dependencies are not clearly defined in the existing literature. We develop response surface-based models, which implicitly employ UWFLO, to quantify and analyze the roles of these other crucial design factors in optimal wind farm planning. The wind pattern at a site can vary significantly from year to year, which is not adequately captured by conventional wind distribution models. The resulting ill-predictability of the annual distribution of wind conditions introduces significant uncertainties in the estimated energy output of the wind farm. A new method is developed to characterize these wind resource uncertainties and model the propagation of these uncertainties into the estimated farm output. The overall wind pattern/regime also varies from one region to another, which demands turbines with capabilities uniquely suited for different wind regimes. Using the UWFLO method, we model the performance potential of currently available turbines for different wind regimes, and quantify their feature-based expected market suitability. Such models can initiate an understanding of the product variation that current turbine manufacturers should pursue, to adequately satisfy the needs of the naturally diverse wind energy market. The wind farm design problems formulated in this dissertation involve highly multimodal objective and constraint functions and a large number of continuous and discrete variables. An effective modification of the PSO algorithm is developed to address such

  3. Effects on harbour porpoises from Roedsand 2 Off-shore Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Teilmann, J.; Tougaard, J.; Carstensen, J.

    2012-11-15

    E.ON Vind Sverige has been commissioned the construction of Roedsand 2 Offshore Wind Farm comprising 90 wind turbines, south of Lolland-Falster, Denmark. The location of the wind farm is 3 km west of the existing Nysted Offshore Wind Farm with 72 turbines. In combination the two wind farms represents the largest wind farm area in the world. Porpoises were monitored by automatic acoustic dataloggers (T-PODs) according to a statistical BACI design and deployed during baseline (Sep 2008-Feb 2009) and during operation (Sep 2011-Mar 2012). These instruments were deployed at 10 stations covering a coastal stretch of 35 km from Gedser to Roedby, including the wind farm area with reference areas on both sides. In addition, background noise at four of the T-POD stations was recorded by automatic noise loggers. In order to assess the potential cumulative effect of two adjacent wind farms, similar data from the Nysted Offshore Wind Farm were also analysed. We found no overall change in echolocation activity over the entire monitoring area from baseline to operation of Roedsand 2 Offshore Wind Farm. Also, there was no significant change in the echolocation activity in Roedsand 2 Offshore Wind Farm relative to each or a combination of the three reference areas, i.e. changes from baseline to operation were similar in the impact and reference areas. Also no significant change in noise levels audible to porpoises was found. This could be due to a generally high noise level in the area, masking the turbine noise or that the noise loggers in the wind farm were deployed between the wind turbines, i.e. at distances {approx}350-450 m from the turbines. This study also shows that the echolocation activity is still significantly lower in Nysted Offshore Wind Farm since the baseline in 2001-2002, although the difference seem to gradually diminish possibly due to a habituation of the porpoises to the wind farm or better feeding posibilities. We found no cumulative effect of the two wind

  4. IEA-Task 31 WAKEBENCH: Towards a protocol for wind farm flow model evaluation. Part 2: Wind farm wake models

    DEFF Research Database (Denmark)

    Moriarty, Patrick; Rodrigo, Javier Sanz; Gancarski, Pawel

    2014-01-01

    Researchers within the International Energy Agency (IEA) Task 31: Wakebench have created a framework for the evaluation of wind farm flow models operating at the microscale level. The framework consists of a model evaluation protocol integrated with a web-based portal for model benchmarking (www.......windbench.net). This paper provides an overview of the building-block validation approach applied to wind farm wake models, including best practices for the benchmarking and data processing procedures for validation datasets from wind farm SCADA and meteorological databases. A hierarchy of test cases has been proposed...

  5. Design tool for offshore wind farm clusters

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Giebel, Gregor; Waldl, Igor

    2015-01-01

    . The software includes wind farm wake models, energy yield models, inter-array and long cable and grid component models, grid code compliance and ancillary services models. The common score for evaluation in order to compare different layouts is levelized cost of energy (LCoE). The integrated DTOC software...... Research Alliance (EERA) and a number of industrial partners. The approach has been to develop a robust, efficient, easy to use and flexible tool, which integrates software relevant for planning offshore wind farms and wind farm clusters and supports the user with a clear optimization work flow...... is developed within the project using open interface standards and is now available as the commercial software product Wind&Economy....

  6. Wind farm policy 1995

    International Nuclear Information System (INIS)

    Anon.

    1995-03-01

    Argyll and Bute District Council, having received a number of planning applications for the erection of wind farms, seeks, in this document, to set out its environmental policy on these installations in line with national government guidelines and those from Strathclyde Regional Council. District Council policy on thirteen environmental issues connected with wind farm construction is set out, covering issues such as environmental impacts on wild-life, noise pollution, access for construction, maintenance and decommissioning vehicles as well as planning consent issues. Recommendations are made to four interested bodies, Strathclyde Regional Council, the Forestry Authority and Scottish Natural Heritage and the Royal Society for the Protection of Birds. (UK)

  7. Modelling, Analysis and Control of DC-connected Wind Farms to Grid

    DEFF Research Database (Denmark)

    Iov, Florin; Sørensen, Poul; Hansen, Anca Daniela

    2006-01-01

    wind turbines/farms are clearly the variable speed operation and a grid connection through a power electronic interface, especially using doubly-fed induction generators. Using power electronics the control capabilities of these wind turbines/farms are extended and thus the grid requirements...... are fulfilled.  However, the traditional squirrel-cage generators based wind turbines/wind farms directly connected to the grid have less control capabilities. These wind turbines/farms cannot regulate their production and contribute to power system stability. A DC transmission system for connection...... of the active stall wind farms to the grid can provide these features and also maximize the produced power especially at low wind speeds by using variable voltage/frequency for the wind farm. The focus in this paper is in studying the variable speed operation for the active stall wind farms using a voltage...

  8. A Research on Wind Farm Micro-sitting Optimization in Complex Terrain

    DEFF Research Database (Denmark)

    Xu, Chang; Yang, Jianchuan; Li, Chenqi

    2013-01-01

    Wind farm layout optimization in complex terrain is a pretty difficult issue for onshore wind farm. In this article, a novel optimization method is proposed to optimize the layout for wind farms in complex terrain. This method utilized Lissaman and Jensen wake models for taking the terrain height...... that the CPSO method has a higher optimal value, and could be used to optimize the actual wind farm micro-sitting engineering projects.......Wind farm layout optimization in complex terrain is a pretty difficult issue for onshore wind farm. In this article, a novel optimization method is proposed to optimize the layout for wind farms in complex terrain. This method utilized Lissaman and Jensen wake models for taking the terrain height...... turbines’ park coordinates which subject to the boundary and minimum distance conditions between two wind turbines. A Cross Particle Swarm Optimization (CPSO) method is developed and applied to optimize the layout for a certain wind farm case. Compared with the uniform and experience method, results show...

  9. Estimation of the Possible Power of a Wind Farm

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Göçmen Bozkurt, Tuhfe; Giebel, Gregor

    2014-01-01

    the possible power calculated based on the estimated effective wind speed of a down regulated wind farm (the industry standard) is compared against the calculated possible power based on the algorithm presented in the paper. The latter takes into account the eect of the wakes of down regulated turbines......It seems possible to increase competitiveness of wind power plants by offering grid services (also called ancillary services) and enter the wind power plants into the ancillary market. One of the ancillary services is called reserve power, the differential capacity between the generated power...... and the available power in the farm. The total amount of energy that a wind farm can potentially generate is called possible power. It is very important for a wind farm owner to have a relatively accurate estimate of the possible power of the wind farm in order to be able to trade the reserve power. In this paper...

  10. Prediction models for wind speed at turbine locations in a wind farm

    DEFF Research Database (Denmark)

    Knudsen, Torben; Bak, Thomas; Soltani, Mohsen

    2011-01-01

    In wind farms, individual turbines disturb the wind field by generating wakes that influence other turbines in the farm. From a control point of view, there is an interest in dynamic optimization of the balance between fatigue and production, and an understanding of the relationship between turbines...... on standard turbine measurements such as rotor speed and power produced, an effective wind speed, which represents the wind field averaged over the rotor disc, is derived. The effective wind speed estimator is based on a continuous–discrete extended Kalman filter that takes advantage of nonlinear time varying...... on the result related to effective wind speed, it is possible to predict wind speeds at neighboring turbines, with a separation of over 700 m, up to 1 min ahead reducing the error by 30% compared with a persistence method. The methodological results are demonstrated on data from an off-shore wind farm...

  11. Review report 2004. The Danish offshore wind farm demonstration project: Horns Rev and Nysted offshore wind farms. Environmental impact assessment and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-10-15

    The present review report presents the two wind farms Horns Rev and Nysted with regard to environmental characteristics and the results of the environmental studies carried out in connection with the Environmental Impact Assessment (EIA) and the baseline and monitoring programmes at the two sites. The descriptions of the programmes are based on extracts from the individual annual reports. Detailed information on method, programmes and conclusions can be found in these reports (see Appendix 1). This review report is divided into two parts. The first part contains a description of the potential environmental impacts of offshore wind farms and the potentially affected part of the environment. The second part includes a description of Horns Rev and Nysted Offshore Wind Farm and the environmental studies carried out here until the end of 2003. Appendix I is a list of the literature published on the studies carried out at Horns Rev and Nysted Offshore Wind Farm. Appendix II is a list of some of the literature relevant to the demonstration projects but not directly related to the projects. The offshore wind farm situated in the Roedsand area is officially denoted Nysted Offshore Wind Farm, and in the present report the denotation 'Nysted' will be used as well when referring to Nysted Offshore Wind Farm. The denotation Roedsand will be used when referring to the actual area Roedsand. (au)

  12. Review report 2003. The Danish offshore wind farm demonstration project: Horns Rev and Nysted offshore wind farms. Environmental impact assessment and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-09-15

    The present review report presents the two wind farms Homs Rev and Nysted, with regard to environmental characteristics and the results of the environmental studies carried out in connection with the Environmental Impact Assessment (EIA) and the baseline and monitoring programmes at the two sites. The descriptions of the programmes are based on extracts from the individual annual reports. Detailed information on methods, programmes and conclusions can be found in these reports. This review report is divided into two parts. The first part contains a description of the potential environmentally impacts of offshore wind farms and the potentially affected part of the environment. The second part includes a description of Horns Rev and Nysted Offshore Wind Farm and the environmental studies carried out here until the end of 2003. Appendix I is a list of the literature published on the studies carried out at Hors Rev and Nysted Offshore Wind Farm. Appendix II is a list of some of the literature relevant to the demonstration projects but not directly related to the projects. The offshore wind farm situated at the bdsand area is officially denoted Nysted Offshore Wind Farm, and in the present report the denotation 'Nysted' will be used as well when referring to Nysted Offshore Wind Farm. The denotation Roedsand will be used when referring to the actual area Roedsand. (au)

  13. Review report 2004. The Danish offshore wind farm demonstration project: Horns Rev and Nysted offshore wind farms. Environmental impact assessment and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-10-15

    The present review report presents the two wind farms Horns Rev and Nysted with regard to environmental characteristics and the results of the environmental studies carried out in connection with the Environmental Impact Assessment (EIA) and the baseline and monitoring programmes at the two sites. The descriptions of the programmes are based on extracts from the individual annual reports. Detailed information on method, programmes and conclusions can be found in these reports (see Appendix 1). This review report is divided into two parts. The first part contains a description of the potential environmental impacts of offshore wind farms and the potentially affected part of the environment. The second part includes a description of Horns Rev and Nysted Offshore Wind Farm and the environmental studies carried out here until the end of 2003. Appendix I is a list of the literature published on the studies carried out at Horns Rev and Nysted Offshore Wind Farm. Appendix II is a list of some of the literature relevant to the demonstration projects but not directly related to the projects. The offshore wind farm situated in the Roedsand area is officially denoted Nysted Offshore Wind Farm, and in the present report the denotation 'Nysted' will be used as well when referring to Nysted Offshore Wind Farm. The denotation Roedsand will be used when referring to the actual area Roedsand. (au)

  14. Modeling and Simulation of a 12 MW Wind Farm

    Directory of Open Access Journals (Sweden)

    GROZA, V.

    2010-05-01

    Full Text Available The installation of wind turbines in power systems has developed rapidly through the last 20 years. In this paper a complete simulation model of a 6 x 2 MW wind turbines is presented using data from a wind farm installed in Denmark. A model of the wind turbine with cage-rotor induction generator is presented in details. A set of simulations are performed and they show that it is possible to simulate a complete wind farm from wind to the grid. The simulation tool can also be used to simulate bigger wind farms connected to the grid.

  15. Power Performance Verification of a Wind Farm Using the Friedman's Test.

    Science.gov (United States)

    Hernandez, Wilmar; López-Presa, José Luis; Maldonado-Correa, Jorge L

    2016-06-03

    In this paper, a method of verification of the power performance of a wind farm is presented. This method is based on the Friedman's test, which is a nonparametric statistical inference technique, and it uses the information that is collected by the SCADA system from the sensors embedded in the wind turbines in order to carry out the power performance verification of a wind farm. Here, the guaranteed power curve of the wind turbines is used as one more wind turbine of the wind farm under assessment, and a multiple comparison method is used to investigate differences between pairs of wind turbines with respect to their power performance. The proposed method says whether the power performance of the specific wind farm under assessment differs significantly from what would be expected, and it also allows wind farm owners to know whether their wind farm has either a perfect power performance or an acceptable power performance. Finally, the power performance verification of an actual wind farm is carried out. The results of the application of the proposed method showed that the power performance of the specific wind farm under assessment was acceptable.

  16. The wind farm business

    International Nuclear Information System (INIS)

    Kirby, T.

    1995-01-01

    This article highlights the tasks to be undertaken by the wind farm business starting with the initial site selection, through the planning stage and the consideration of technical matters, to the implementation and financial aspects. The current situation in the UK with regard to installed wind turbines, public attitude, and future prospects are discussed. (UK)

  17. An Improved Adaptive-Torque-Gain MPPT Control for Direct-Driven PMSG Wind Turbines Considering Wind Farm Turbulences

    Directory of Open Access Journals (Sweden)

    Xiaolian Zhang

    2016-11-01

    Full Text Available Maximum power point tracking (MPPT plays an important role in increasing the efficiency of a wind energy conversion system (WECS. In this paper, three conventional MPPT methods are reviewed: power signal feedback (PSF control, decreased torque gain (DTG control, and adaptive torque gain (ATG control, and their potential challenges are investigated. It is found out that the conventional MPPT method ignores the effect of wind turbine inertia and wind speed fluctuations, which lowers WECS efficiency. Accordingly, an improved adaptive torque gain (IATG method is proposed, which customizes adaptive torque gains and enhances MPPT performances. Specifically, the IATG control considers wind farm turbulences and works out the relationship between the optimal torque gains and the wind speed characteristics, which has not been reported in the literature. The IATG control is promising, especially under the ongoing trend of building wind farms with large-scale wind turbines and at low and medium wind speed sites.

  18. Comparison of the effectiveness of analytical wake models for wind farm with constant and variable hub heights

    International Nuclear Information System (INIS)

    Wang, Longyan; Tan, Andy C.C.; Cholette, Michael; Gu, Yuantong

    2016-01-01

    Highlights: • The effectiveness of three analytical wake models is studied. • The results of the analytical wake models are compared with the CFD simulations. • The results of CFD simulation are verified by comparison to the offshore wind farm observation data. • The onshore wind farm with both constant and different hub height turbines are analyzed. • PARK model is able to predict the total wind farm power production well with tuned surface roughness value. - Abstract: Extensive power losses of wind farm have been witnessed due to the wake interactions between wind turbines. By applying analytical wake models which describe the wind speed deficits in the wake quantitatively, the power losses can be regained to a large extent through wind farm layout optimization, and this has been extensively reported in literature. Nevertheless, the effectiveness of the analytical wake models in predicting the wind farm power production have rarely been studied and compared for wind farm with both constant and variable wind turbine hub heights. In this study, the effectiveness of three different analytical wake models (PARK model, Larsen model and B-P model) is thoroughly compared over a wide range of wake properties. After the validation with the observation data from offshore wind farm, CFD simulations are used to verify the effectiveness of the analytical wake models for an onshore wind farm. The results show that when using the PARK model the surface roughness value (z 0 ) must be carefully tuned to achieve good performance in predicting the wind farm power production. For the other two analytical wake models, their effectiveness varies depending on the situation of wind farm (offshore or onshore) and the wind turbine hub heights (constant or variable). It was found that the results of B-P model agree well with the CFD simulations for offshore wind farm, but not for the onshore wind farm. The Larsen model is more accurate for the wind farm with variable wind turbine

  19. Multi-criteria decision making on strategic selection of wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Amy H.I. [Department of Industrial Engineering and System Management, Chung Hua University, Hsinchu (China); Chen, Hsing Hung [Faculty of Management and Administration, Macau University of Science and Technology, Taipa (Macau); Kang, He-Yau [Department of Industrial Engineering and Management, National Chin-Yi University of Technology, Taiping, Taichung (China)

    2009-01-15

    With maturity of advanced technologies and urgent requirement for maintaining a healthy environment with reasonable price, China is moving toward a trend of generating electricity from renewable wind resources. How to select a suitable wind farm becomes an important focus for stakeholders. This paper first briefly introduces wind farm and then develops its critical success criteria. A new multi-criteria decision-making (MCDM) model, based on the analytic hierarchy process (AHP) associated with benefits, opportunities, costs and risks (BOCR), is proposed to help select a suitable wind farm project. Multiple factors that affect the success of wind farm operations are analyzed by taking into account experts' opinions, and a performance ranking of the wind farms is generated. (author)

  20. Large-Eddy Simulation of Waked Turbines in a Scaled Wind Farm Facility

    Science.gov (United States)

    Wang, J.; McLean, D.; Campagnolo, F.; Yu, T.; Bottasso, C. L.

    2017-05-01

    The aim of this paper is to present the numerical simulation of waked scaled wind turbines operating in a boundary layer wind tunnel. The simulation uses a LES-lifting-line numerical model. An immersed boundary method in conjunction with an adequate wall model is used to represent the effects of both the wind turbine nacelle and tower, which are shown to have a considerable effect on the wake behavior. Multi-airfoil data calibrated at different Reynolds numbers are used to account for the lift and drag characteristics at the low and varying Reynolds conditions encountered in the experiments. The present study focuses on low turbulence inflow conditions and inflow non-uniformity due to wind tunnel characteristics, while higher turbulence conditions are considered in a separate study. The numerical model is validated by using experimental data obtained during test campaigns conducted with the scaled wind farm facility. The simulation and experimental results are compared in terms of power capture, rotor thrust, downstream velocity profiles and turbulence intensity.

  1. Active Power Control of Waked Wind Farms: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Paul A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); van Wingerden, Jan-Willem [Delft University of Technology; Pao, Lucy [University of Colorado; Aho, Jacob [University of Colorado

    2017-08-15

    Active power control can be used to balance the total power generated by wind farms with the power consumed on the electricity grid. With the increasing penetration levels of wind energy, there is an increasing need for this ancillary service. In this paper, we show that the tracking of a certain power reference signal provided by the transmission system operator can be significantly improved by using feedback control at the wind farm level. We propose a simple feedback control law that significantly improves the tracking behavior of the total power output of the farm, resulting in higher performance scores. The effectiveness of the proposed feedback controller is demonstrated using high-fidelity computational fluid dynamics simulations of a small wind farm.

  2. Onshore Wind Farms: Value Creation for Stakeholders in Lithuania

    Science.gov (United States)

    Burinskienė, Marija; Rudzkis, Paulius; Kanopka, Adomas

    With the costs of fossil fuel consistently rising worldwide over the last decade, the development of green technologies has become a major goal in many countries. Therefore the evaluation of wind power projects becomes a very important task. To estimate the value of the technologies based on renewable resources also means taking into consideration social, economic, environmental, and scientific value of such projects. This article deals with economic evaluation of electricity generation costs of onshore wind farms in Lithuania and the key factors that have influence on wind power projects and offer a better understanding of social-economic context behind wind power projects. To achieve these goals, this article makes use of empirical data of Lithuania's wind power farms as well as data about the investment environment of the country.Based on empirical data of wind power parks, the research investigates the average wind farm generation efficiency in Lithuania. Employing statistical methods the return on investments of wind farms in Lithuania is calculated. The value created for every party involved and the total value of the wind farm is estimated according to Stakeholder theory.

  3. Moroccan wind farm potential feasibility. Case study

    International Nuclear Information System (INIS)

    Nouri, Abdellatif; Ait Babram, Mohamed; Elwarraki, Elmostafa; Enzili, Mustapha

    2016-01-01

    Highlights: • A new methodology for the technical feasibility of wind farm potentials is proposed. • The wind resources of two different sites in Morocco are compared. • Comparison between short and long term data using multivariate analysis is made. • Geographic information system implementation. • A 10 MW wind farm is designed and optimized. - Abstract: The subject of this paper is the elaboration of a methodology to study the technical feasibility of a wind farm potential. The implementation of this methodology allows a comparison between the wind resources of two different sites in Morocco. One site is located in the region of Essaouira, whereas the other one is located in the region of Safi. The comparison is based on real wind data collected from two masts at the heights of 30, 50, and 60 m. Each of the masts is installed at one of the mentioned potential sites over a fixed time period, lasting fifteen months for the first site, and eight months for the second one. The aim is the determination of the most applicable site presenting a good potential for a statistical study in order to predict long-term wind behaviors. Thus, the geographical situation study of the chosen site including topography, roughness and obstacles, is carried out. Furthermore, the wind resource using data, generated by the measuring masts, is evaluated. Finally, the areas which present great wind potential are located and the wind farm turbine locations are optimized by using the WAsP software.

  4. Using Wind Tunnels to Predict Bird Mortality in Wind Farms: The Case of Griffon Vultures

    OpenAIRE

    de Lucas, Manuela; Ferrer, Miguel; Janss, Guyonne F. E.

    2012-01-01

    Background: Wind farms have shown a spectacular growth during the last 15 years. Avian mortality through collision with moving rotor blades is well-known as one of the main adverse impacts of wind farms. In Spain, the griffon vulture incurs the highest mortality rates in wind farms. Methodology/Principal Findings: As far as we know, this study is the first attempt to predict flight trajectories of birds in order to foresee potentially dangerous areas for wind farm development. We analyse topo...

  5. A Response Surface-Based Cost Model for Wind Farm Design

    International Nuclear Information System (INIS)

    Zhang Jie; Chowdhury, Souma; Messac, Achille; Castillo, Luciano

    2012-01-01

    A Response Surface-Based Wind Farm Cost (RS-WFC) model is developed for the engineering planning of wind farms. The RS-WFC model is developed using Extended Radial Basis Functions (E-RBF) for onshore wind farms in the U.S. This model is then used to explore the influences of different design and economic parameters, including number of turbines, rotor diameter and labor cost, on the cost of a wind farm. The RS-WFC model is composed of three components that estimate the effects of engineering and economic factors on (i) the installation cost, (ii) the annual Operation and Maintenance (O and M) cost, and (iii) the total annual cost of a wind farm. The accuracy of the cost model is favorably established through comparison with pertinent commercial data. The final RS-WFC model provided interesting insights into cost variation with respect to critical engineering and economic parameters. In addition, a newly developed analytical wind farm engineering model is used to determine the power generated by the farm, and the subsequent Cost of Energy (COE). This COE is optimized for a unidirectional uniform “incoming wind speed” scenario using Particle Swarm Optimization (PSO). We found that the COE could be appreciably minimized through layout optimization, thereby yielding significant cost savings. - Highlights: ► We present a Response Surface-Based Wind Farm Cost (RS-WFC) model for wind farm design. ► The model could estimate installation cost, Operation and Maintenance cost, and total annual cost of a wind farm. ► The Cost of Energy is optimized using Particle Swarm Optimization. ► Layout optimization could yield significant cost savings.

  6. Gradient-Based Optimization of Wind Farms with Different Turbine Heights

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, Andrew P. J.; Thomas, Jared; Ning, Andrew; Annoni, Jennifer; Dykes, Katherine; Fleming, Paul

    2017-01-09

    Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5%-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and a low wind shear exponent.

  7. Results of Sexbierum Wind Farm: single wake measurements

    NARCIS (Netherlands)

    Cleijne, J.W.

    1993-01-01

    In the framework of the JOULE-0064 'Full-scale Measurements in Wind Turbine Arrays' in the period between June-November 1992 measurements have been performed in the Sexbierum Wind Farm. The aim of the measurements is to provide data for the validation of wake and wind farm models, which are being

  8. Development of FAST.Farm: A New Multiphysics Engineering Tool for Wind Farm Design and Analysis: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, Jason; Annoni, Jennifer; Hayman, Greg; Jonkman, Bonnie; Purkayastha, Avi

    2017-01-01

    This paper presents the development of FAST.Farm, a new multiphysics tool applicable to engineering problems in research and industry involving wind farm performance and cost optimization that is needed to address the current underperformance, failures, and expenses plaguing the wind industry. Achieving wind cost-of-energy targets - which requires improvements in wind farm performance and reliability, together with reduced uncertainty and expenditures - has been eluded by the complicated nature of the wind farm design problem, especially the sophisticated interaction between atmospheric phenomena and wake dynamics and array effects. FAST.Farm aims to balance the need for accurate modeling of the relevant physics for predicting power performance and loads while maintaining low computational cost to support a highly iterative and probabilistic design process and system-wide optimization. FAST.Farm makes use of FAST to model the aero-hydro-servo-elastics of distinct turbines in the wind farm, and it is based on some of the principles of the Dynamic Wake Meandering (DWM) model, but avoids many of the limitations of existing DWM implementations.

  9. Wind Turbine Power Curve Design for Optimal Power Generation in Wind Farms Considering Wake Effect

    Directory of Open Access Journals (Sweden)

    Jie Tian

    2017-03-01

    Full Text Available In modern wind farms, maximum power point tracking (MPPT is widely implemented. Using the MPPT method, each individual wind turbine is controlled by its pitch angle and tip speed ratio to generate the maximum active power. In a wind farm, the upstream wind turbine may cause power loss to its downstream wind turbines due to the wake effect. According to the wake model, downstream power loss is also determined by the pitch angle and tip speed ratio of the upstream wind turbine. By optimizing the pitch angle and tip speed ratio of each wind turbine, the total active power of the wind farm can be increased. In this paper, the optimal pitch angle and tip speed ratio are selected for each wind turbine by the exhausted search. Considering the estimation error of the wake model, a solution to implement the optimized pitch angle and tip speed ratio is proposed, which is to generate the optimal control curves for each individual wind turbine off-line. In typical wind farms with regular layout, based on the detailed analysis of the influence of pitch angle and tip speed ratio on the total active power of the wind farm by the exhausted search, the optimization is simplified with the reduced computation complexity. By using the optimized control curves, the annual energy production (AEP is increased by 1.03% compared to using the MPPT method in a case-study of a typical eighty-turbine wind farm.

  10. On wake modeling, wind-farm gradients and AEP predictions at the Anholt wind farm

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Hansen, Kurt Schaldemose; Ott, Søren

    2017-01-01

    of the mesoscale simulations and supervisory control and data acquisition (SCADA), we show that for westerly flow in particular, there is a clear horizontal wind-speed gradient over the wind farm. We also use the mesoscale simulations to derive the undisturbed inflow conditions that are coupled with three commonly....... When looking at westerly flow wake cases, where the impact of the horizontal wind-speed gradient on the power of the undisturbed turbines is largest, the wake models agree with the SCADA fairly well; when looking at a southerly flow case, where the wake losses are highest, the wake models tend...... to underestimate the wake loss. With the mesoscale-wake model setup, we are also able to estimate the capacity factor of the wind farm rather well when compared to that derived from the SCADA. Finally, we estimate the uncertainty of the wake models by bootstrapping the SCADA. The models tend to underestimate...

  11. OffWindSolver: Wind farm design tool based on actuator line/actuator disk concept in OpenFoam architecture

    Directory of Open Access Journals (Sweden)

    Panjwani Balram

    2014-01-01

    Full Text Available Wind energy is a good alternative to meet the energy requirements in some parts of the world; however the efficiency of wind farm depends on the optimized location of the wind turbines. Therefore a software tool that is capable of predicting the in-situ performance of multiple turbine installations in different operating conditions with reliable accuracy is needed. In present study wind farm layout design tool OffWindSolver is developed within the OpenFoam architecture. Unsteady PisoFoam solver is extended to account for wind turbines, where each turbine is modeled as a sink term in the momentum equation. Turbine modeling is based on actuator line concepts derived from SOWFA code, where each blade of the turbine is represented as a line. The loading on each line/blade of the turbine is estimated using the Blade Element Method (BEM. The inputs for the solver are tabulated airfoil aerodynamic data, dimension and height of the wind turbines, wind magnitude and direction. OffWindSolver is validated for a real wind farm – Lillgrund offshore facility in Sweden/Denmark operated by Vattenfall Vindkraft AB. Because of the scale of the computation, we only examine the effect of wind from one direction at one speed. In the absence of time dependent Marine Atmospheric Boundary Layer (MABL, a log wind profile with surface roughness of 0.04 is used at the inlet. The simulated power production of each turbine is compared to the field data and large-eddy simulation. The overall power of the wind farm is well predicted. The simulation shows the significant decreases of the power for those turbines that were in the wake.

  12. Electrical system studies for the grid connection of wind farms

    International Nuclear Information System (INIS)

    Arp, K.; Hanson, J.; Hopp, S.; Zimmermann, W.

    2007-01-01

    Wind power is gaining momentum in the world's energy balance. Several issues have to be addressed whenever power-generating devices are connected to the grid. The paper describes studies needed to evaluate the influence of wind farms on the connected transmission system and how faults in the system impact on induction generators in a wind farm. Some generalized results of studies for an offshore wind farm in the North Sea and a Bulgarian wind farm show how studies can influence the layout of the internal network and the electrical equipment. (authors)

  13. Analysis of a commercial wind farm in Taiwan

    DEFF Research Database (Denmark)

    Wang, Li; Yeh, Tai-Her; Lee, Wei-Jen

    2009-01-01

    wind farm. With twenty-three 2-MW DFIG-type wind turbine generators, this wind farm is connected to the 161-kV extra high-voltage substation of Taiwan Power System through a 23/161-kV, 60-MVA step-up main transformer from six feeders. Through comparing field measured results, this paper establishes...

  14. Lightning Damage to Wind Turbine Blades From Wind Farms in the U.S

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Madsen, Søren Find; Nissim, Maya

    2016-01-01

    , laminate structure, and lightning protection systems. The statistics consist of the distribution of lightning damage along the blade and classify the damage by severity. In addition, the frequency of lightning damage to more than one blade of a wind turbine after a thunderstorm is assessed. The results......This paper presents statistical data about lightning damage on wind turbine blades reported at different wind farms in the U.S. The analysis is based on 304 cases of damage due to direct lightning attachment on the blade surface. This study includes a large variety of blades with different lengths...

  15. Development of a generic wind farm SCADA system

    Energy Technology Data Exchange (ETDEWEB)

    Smith, G.

    2001-07-01

    The aim of the project is to develop a 'Generic Wind Farm Supervisory Control and Data Acquisition (SCADA) System' for the wind energy industry. A SCADA is a computer-based system that allows local and remote control of basic wind turbine functions and collects data from the wind farm that can be used to analyse and report on the operational performance. As wind farm size, complexity and remoteness of location increase an industry standard SCADA is vitally important to allow effective operation, monitoring, control and reporting. Turbine manufacturers offer a number of existing systems but these do not always fully meet the needs of wind farm operators and owners. Operators and owners who are involved with more than one turbine supplier end up with a number of incompatible systems. This causes operational difficulties and makes it hard to compared performance data from different turbines. This project aims to address these issues and develop a system that will communicate with all turbine types and calculate and store performance data in a consistent way. (Author)

  16. Wind farm struggles in Flanders fields: A sociological perspective

    International Nuclear Information System (INIS)

    Pepermans, Yves; Loots, Ilse

    2013-01-01

    In this article we analyse how protests against wind farms reflect symbolic distances or alienations, typical to Flanders (Belgium), as consequences of wider societal trends. A thorough qualitative study of three wind farm projects in Flanders, including group discussions and interviews with crucial stakeholders, shows that the current siting process reinforces disagreements and leads to a stalemate between different framings of the wind farms. Using insights from our case studies and the literature, we argue for spatial planning which strives for a negotiation over acceptable solutions rather than acceptance of fixed proposals. - Highlights: • Flemish wind farm siting is characterized by social, spatial and political distances. • These symbolic distances make the legitimacy of new infrastructure less self-evident. • The current ‘decide-announce and defend’ siting procedure is a problem for acceptance. • We propose a siting procedure for wind farms which allows democratic debate over alternatives between stakeholders

  17. Modeling and Identification of Harmonic Instability Problems In Wind Farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2016-01-01

    In power electronics based power systems like wind farms, the interactions between the inner control systems of the power converters and the passive components may lead to high frequency oscillations, which can be called harmonic instability. In this paper, a simple methodology is presented...... to identify harmonic instability problems in wind farms, where many wind turbines, cables, transformers, capacitor banks, shunt reactors, etc, typically are located. This methodology introduces the wind farm as a Multi-Input Multi-Outpur (MIMO) control system, where the linearized models of fast inner control....../EMTDC software environment for a 400-MW wind farm. The proposed analytical analysis method and time-domain simulation results show that both dynamics of the power electronic converter and the parameters of the passive component can effect on the wind farm stability....

  18. Wind Farm-LA Coordinated Operation Mode and Dispatch Model in Wind Power Accommodation Promotion

    Directory of Open Access Journals (Sweden)

    Li Lin

    2018-05-01

    Full Text Available With the support of a smart grid, a load aggregator (LA that aggregates the demand response resources of small- and medium-sized customers to participate in the electricity market would be a novel way to promote wind power accommodation. This paper proposes a wind farm–LA coordinated operation mode (WLCOM, which enables LAs to deal with wind farms directly at an agreement price. Afterwards, according to the accommodation demand of the wind farm, a coordinated dispatch model taking advantage of the various response capabilities of different flexible loads is set up to maximize the revenue of the LA. A case study was conducted to demonstrate the effectiveness of the proposed WLCOM and the coordinated dispatch model. The demonstration indicates that: (a load fluctuations and wind curtailment were obviously reduced; and (b both the LA and the wind farm participating in coordinated operation obtained higher revenues. Factors that influence the accommodation level, as well as revenues of wind farms and LA, are also investigated.

  19. Large-scale offshore wind farms in Denmark. Update of ''Future offshore sites for wind turbines 2025''; Stor-skala havmoelleparker i Danmark. Opdatering af fremtidens havmoelleplaceringer

    Energy Technology Data Exchange (ETDEWEB)

    2011-04-15

    This updating of the ''Future offshore sites for wind turbines 2025'', is made by the Offshore Wind Farm Committee and adjusts primarily the existing sites in relation to a updated data basis. The sites are adjusted within the already identified areas, and no new areas are therefore included. In addition to an update of the underlying data base, including the revised sailing routes, the new Natura 2000 sites and mineral resources, there are now further collected knowledge about the seabed in the designated areas. Moreover, the underlying assumptions for construction costs and grid connection updated, which has resulted in a revised socio-economic priority of the areas. The Offshore Wind Farm Committee's report confirms that the placement of the 600 MW Kriegers Flak Offshore Wind Farm in the Baltic Sea is the best location for Denmark's next major offshore wind farm. Kriegers Flak Offshore Wind Farm is already included in the Government's energy strategy. (LN)

  20. Optimization of wind farm turbines layout using an evolutive algorithm

    International Nuclear Information System (INIS)

    Gonzalez, Javier Serrano; Santos, Jesus Riquelme; Payan, Manuel Burgos; Gonzalez Rodriguez, Angel G.; Mora, Jose Castro

    2010-01-01

    The optimum wind farm configuration problem is discussed in this paper and an evolutive algorithm to optimize the wind farm layout is proposed. The algorithm's optimization process is based on a global wind farm cost model using the initial investment and the present value of the yearly net cash flow during the entire wind-farm life span. The proposed algorithm calculates the yearly income due to the sale of the net generated energy taking into account the individual wind turbine loss of production due to wake decay effects and it can deal with areas or terrains with non-uniform load-bearing capacity soil and different roughness length for every wind direction or restrictions such as forbidden areas or limitations in the number of wind turbines or the investment. The results are first favorably compared with those previously published and a second collection of test cases is used to proof the performance and suitability of the proposed evolutive algorithm to find the optimum wind farm configuration. (author)

  1. A static VAR compensator model for improved ride-through capability of wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Akhmatov, V.; Soebrink, K.

    2004-12-01

    Dynamic reactive compensation is associated with reactive power and voltage control of induction generator based wind turbines. With regard to wind power, application areas of dynamic reactive compensation can be improvement of the power quality and the voltage stability, the control of the reactive power exchange between the wind farm and the power grid in the wind farm connection point as well as improvement of the ride-through capability of the wind farm. This article presents a model of a Static VAR Compensator (SVC) with dynamic generic control that is a kind of dynamic reactive compensation device. The term 'generic' implies that the model is general and must cover a variety of the SVC units and their specific controls from different manufacturers. The SVC model with dynamic generic control is implemented by Eltra in the simulation tool Powerfactory and validated from the SVC model in the tool PSCAD/EMTDC. Implementation in the tool Powerfactory makes it possible to apply the SVC model with dynamic generic control in investigations of power system stability with regard to establishment of large wind farms without restrictions on the model size of the power grid. (Author)

  2. The Explicit Wake Parametrisation V1.0: a wind farm parametrisation in the mesoscale model WRF

    Directory of Open Access Journals (Sweden)

    P. J. H. Volker

    2015-11-01

    Full Text Available We describe the theoretical basis, implementation, and validation of a new parametrisation that accounts for the effect of large offshore wind farms on the atmosphere and can be used in mesoscale and large-scale atmospheric models. This new parametrisation, referred to as the Explicit Wake Parametrisation (EWP, uses classical wake theory to describe the unresolved wake expansion. The EWP scheme is validated for a neutral atmospheric boundary layer against filtered in situ measurements from two meteorological masts situated a few kilometres away from the Danish offshore wind farm Horns Rev I. The simulated velocity deficit in the wake of the wind farm compares well to that observed in the measurements, and the velocity profile is qualitatively similar to that simulated with large eddy simulation models and from wind tunnel studies. At the same time, the validation process highlights the challenges in verifying such models with real observations.

  3. Making space for wind farms: Practices of territorial stigmatisation in rural Denmark

    DEFF Research Database (Denmark)

    Rudolph, David Philipp; Kirkegaard, Julia Kirch

    of territorial stigmatisation are mobilised and aligned by developers and municipalities in order to make space for and legitimise large wind farm projects in rural areas. In doing so, the paper will illustrate how stigmatisation practices are embedded in discourses of rurality as ‘Outskirts......Whilst issues of siting wind farms have mostly revolved around their public acceptance resulting from an unequal distribution of local costs and benefits, the perceived fairness of the planning process and the disruption of places, the challenge of finding adequate locations and getting access...... community involvement and ownership of wind farms, access to diminishing spatial resources reflects a key concern for developers, while putting the role of private landowners at the core of successful projects. By drawing on case studies from rural Northern Denmark it will be demonstrated how narratives...

  4. Analyzing complex wake-terrain interactions and its implications on wind-farm performance.

    Science.gov (United States)

    Tabib, Mandar; Rasheed, Adil; Fuchs, Franz

    2016-09-01

    Rotating wind turbine blades generate complex wakes involving vortices (helical tip-vortex, root-vortex etc.).These wakes are regions of high velocity deficits and high turbulence intensities and they tend to degrade the performance of down-stream turbines. Hence, a conservative inter-turbine distance of up-to 10 times turbine diameter (10D) is sometimes used in wind-farm layout (particularly in cases of flat terrain). This ensures that wake-effects will not reduce the overall wind-farm performance, but this leads to larger land footprint for establishing a wind-farm. In-case of complex-terrain, within a short distance (say 10D) itself, the nearby terrain can rise in altitude and be high enough to influence the wake dynamics. This wake-terrain interaction can happen either (a) indirectly, through an interaction of wake (both near tip vortex and far wake large-scale vortex) with terrain induced turbulence (especially, smaller eddies generated by small ridges within the terrain) or (b) directly, by obstructing the wake-region partially or fully in its flow-path. Hence, enhanced understanding of wake- development due to wake-terrain interaction will help in wind farm design. To this end the current study involves: (1) understanding the numerics for successful simulation of vortices, (2) understanding fundamental vortex-terrain interaction mechanism through studies devoted to interaction of a single vortex with different terrains, (3) relating influence of vortex-terrain interactions to performance of a wind-farm by studying a multi-turbine wind-farm layout under different terrains. The results on interaction of terrain and vortex has shown a much faster decay of vortex for complex terrain compared to a flatter-terrain. The potential reasons identified explaining the observation are (a) formation of secondary vortices in flow and its interaction with the primary vortex and (b) enhanced vorticity diffusion due to increased terrain-induced turbulence. The implications of

  5. Modeling large offshore wind farms under different atmospheric stability regimes with the Park wake model

    DEFF Research Database (Denmark)

    Peña, Alfredo; Réthoré, Pierre-Elouan; Rathmann, Ole

    2013-01-01

    Here, we evaluate a modified version of the Park wake model against power data from a west-east row in the middle of the Horns Rev I offshore wind farm. The evaluation is performed on data classified in four different atmospheric stability conditions, for a narrow wind speed range, and a wide ran...

  6. A model to predict the power output from wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Landberg, L. [Riso National Lab., Roskilde (Denmark)

    1997-12-31

    This paper will describe a model that can predict the power output from wind farms. To give examples of input the model is applied to a wind farm in Texas. The predictions are generated from forecasts from the NGM model of NCEP. These predictions are made valid at individual sites (wind farms) by applying a matrix calculated by the sub-models of WASP (Wind Atlas Application and Analysis Program). The actual wind farm production is calculated using the Riso PARK model. Because of the preliminary nature of the results, they will not be given. However, similar results from Europe will be given.

  7. Using wind tunnels to predict bird mortality in wind farms: the case of griffon vultures.

    Science.gov (United States)

    de Lucas, Manuela; Ferrer, Miguel; Janss, Guyonne F E

    2012-01-01

    Wind farms have shown a spectacular growth during the last 15 years. Avian mortality through collision with moving rotor blades is well-known as one of the main adverse impacts of wind farms. In Spain, the griffon vulture incurs the highest mortality rates in wind farms. As far as we know, this study is the first attempt to predict flight trajectories of birds in order to foresee potentially dangerous areas for wind farm development. We analyse topography and wind flows in relation to flight paths of griffon vultures, using a scaled model of the wind farm area in an aerodynamic wind tunnel, and test the difference between the observed flight paths of griffon vultures and the predominant wind flows. Different wind currents for each wind direction in the aerodynamic model were observed. Simulations of wind flows in a wind tunnel were compared with observed flight paths of griffon vultures. No statistical differences were detected between the observed flight trajectories of griffon vultures and the wind passages observed in our wind tunnel model. A significant correlation was found between dead vultures predicted proportion of vultures crossing those cells according to the aerodynamic model. Griffon vulture flight routes matched the predominant wind flows in the area (i.e. they followed the routes where less flight effort was needed). We suggest using these kinds of simulations to predict flight paths over complex terrains can inform the location of wind turbines and thereby reduce soaring bird mortality.

  8. Comparing offshore wind farm wake observed from satellite SAR and wake model results

    Science.gov (United States)

    Bay Hasager, Charlotte

    2014-05-01

    Offshore winds can be observed from satellite synthetic aperture radar (SAR). In the FP7 EERA DTOC project, the European Energy Research Alliance project on Design Tools for Offshore Wind Farm Clusters, there is focus on mid- to far-field wind farm wakes. The more wind farms are constructed nearby other wind farms, the more is the potential loss in annual energy production in all neighboring wind farms due to wind farm cluster effects. It is of course dependent upon the prevailing wind directions and wind speed levels, the distance between the wind farms, the wind turbine sizes and spacing. Some knowledge is available within wind farm arrays and in the near-field from various investigations. There are 58 offshore wind farms in the Northern European seas grid connected and in operation. Several of those are spaced near each other. There are several twin wind farms in operation including Nysted-1 and Rødsand-2 in the Baltic Sea, and Horns Rev 1 and Horns Rev 2, Egmond aan Zee and Prinses Amalia, and Thompton 1 and Thompton 2 all in the North Sea. There are ambitious plans of constructing numerous wind farms - great clusters of offshore wind farms. Current investigation of offshore wind farms includes mapping from high-resolution satellite SAR of several of the offshore wind farms in operation in the North Sea. Around 20 images with wind farm wake cases have been retrieved and processed. The data are from the Canadian RADARSAT-1/-2 satellites. These observe in microwave C-band and have been used for ocean surface wind retrieval during several years. The satellite wind maps are valid at 10 m above sea level. The wakes are identified in the raw images as darker areas downwind of the wind farms. In the SAR-based wind maps the wake deficit is found as areas of lower winds downwind of the wind farms compared to parallel undisturbed flow in the flow direction. The wind direction is clearly visible from lee effects and wind streaks in the images. The wind farm wake cases

  9. Output Power Smoothing Control for a Wind Farm Based on the Allocation of Wind Turbines

    Directory of Open Access Journals (Sweden)

    Ying Zhu

    2018-06-01

    Full Text Available This paper presents a new output power smoothing control strategy for a wind farm based on the allocation of wind turbines. The wind turbines in the wind farm are divided into control wind turbines (CWT and power wind turbines (PWT, separately. The PWTs are expected to output as much power as possible and a maximum power point tracking (MPPT control strategy combining the rotor inertia based power smoothing method is adopted. The CWTs are in charge of the output power smoothing for the whole wind farm by giving the calculated appropriate power. The battery energy storage system (BESS with small capacity is installed to be the support and its charge and discharge times are greatly reduced comparing with the traditional ESSs based power smoothing strategies. The simulation model of the permanent magnet synchronous generators (PMSG based wind farm by considering the wake effect is built in Matlab/Simulink to test the proposed power smoothing method. Three different working modes of the wind farm are given in the simulation and the simulation results verify the effectiveness of the proposed power smoothing control strategy.

  10. Evaluation of the wind direction uncertainty and its impact on wake modeling at the Horns Rev offshore wind farm

    DEFF Research Database (Denmark)

    Gaumond, M.; Réthoré, Pierre-Elouan; Ott, Søren

    2014-01-01

    of the wind direction inside the wind farm and the variability of the wind direction within the averaging period. The results show that the technique corrects the predictions of the models when the simulations and data are averaged over narrow wind direction sectors. In addition, the agreement of the shape...... of the power deficit in a single wake situation is improved. The robustness of the method is verified using the Jensen model, the Larsen model and Fuga, which are three different engineering wake models. The results indicate that the discrepancies between the traditional numerical simulations and power...... production data for narrow wind direction sectors are not caused by an inherent inaccuracy of the current wake models, but rather by the large wind direction uncertainty included in the dataset. The technique can potentially improve wind farm control algorithms and layout optimization because both...

  11. TOPFARM: Multi-fidelity optimization of wind farms

    DEFF Research Database (Denmark)

    Réthoré, Pierre-Elouan; Fuglsang, Peter; Larsen, Gunner Chr.

    2014-01-01

    design of the Middelgrunden wind farm, this work focuses on demonstrating a method that optimizes the profit of wind farms over their lifetime based on a balance of the energy production income, the electrical grid costs, the foundations cost, and the cost of wake turbulence induced fatigue degradation...... of different wind turbine components. A multi-fidelity concept is adapted, which uses cost function models of increasing complexity (and decreasing speed) to accelerate the convergence to an optimum solution. In the EU-FP6 TOPFARM project, three levels of complexity are considered. The first level uses...... a simple stationary wind farm wake model to estimate the Annual Energy Production (AEP), a foundations cost model depending on the water depth and an electrical grid cost function dictated by cable length. The second level calculates the AEP and adds a wake-induced fatigue degradation cost function...

  12. Optimization of offshore wind farm layout in restricted zones

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Cong

    2016-01-01

    In this research, an optimization method for offshore wind farm layout design is proposed. With the purpose of maximizing the energy production of the wind farm, the wind turbine (WT) positions are optimized. Due to the limitations of seabed conditions, marine traffic limitations or shipwrecks, etc...... with multiple adaptive methods (PSO-MAM) is adopted. The simulation results indicate that the proposed method can find a layout which outperforms a baseline layout of a reference wind farm (RWF) by increasing the energy yield by 3.84%....

  13. Wind farm electrical power production model for load flow analysis

    International Nuclear Information System (INIS)

    Segura-Heras, Isidoro; Escriva-Escriva, Guillermo; Alcazar-Ortega, Manuel

    2011-01-01

    The importance of renewable energy increases in activities relating to new forms of managing and operating electrical power: especially wind power. Wind generation is increasing its share in the electricity generation portfolios of many countries. Wind power production in Spain has doubled over the past four years and has reached 20 GW. One of the greatest problems facing wind farms is that the electrical power generated depends on the variable characteristics of the wind. To become competitive in a liberalized market, the reliability of wind energy must be guaranteed. Good local wind forecasts are therefore essential for the accurate prediction of generation levels for each moment of the day. This paper proposes an electrical power production model for wind farms based on a new method that produces correlated wind speeds for various wind farms. This method enables a reliable evaluation of the impact of new wind farms on the high-voltage distribution grid. (author)

  14. Reactive Power Compensation of a 24 MW Wind Farm using a 12-Pulse Voltage Source Converter

    DEFF Research Database (Denmark)

    Pedersen, Knud Ole Helgesen; Pedersen, Jørgen Kaas

    1998-01-01

    Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop and investig......Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop...... and investigate the use of a STATCOM by modelling and field testing an 8 MVar unit in a 24 MW wind farm....

  15. Scavenger removal: Bird and bat carcass persistence in a tropical wind farm

    Science.gov (United States)

    Villegas-Patraca, Rafael; Macías-Sánchez, Samuel; MacGregor-Fors, Ian; Muñoz-Robles, Carlos

    2012-08-01

    Energy produced by wind farms has diverse positive environmental effects, but can also be related to negative impacts, including wildlife mortality through collisions with wind turbines. Bird and bat mortality caused by collisions with wind turbines can be estimated indirectly by counting carcasses within wind farms. However, carcass removal by scavengers often biases such measurements. In this study, we identified the main scavengers removing bird and bat carcasses in a tropical wind farm. A known fate analysis was done to assess the effect of carcass type (i.e., small bird, large bird, bat), vegetation type (i.e., secondary vegetation, croplands) and season (dry and rainy seasons of 2009) on carcass persistence rates. We identified three main scavenger groups, with mammals being the most abundant group. Our results show high rates of carcass removal relative to previous studies, especially for bats; there were fewer remaining carcasses after 20 days in our tropical site than in non-tropical environments reported elsewhere. We found a higher carcass persistence rate during the rainy season than in the dry season, possibly due to a greater abundance of food resources for scavenger organisms in the rainy season. Although we found some evidence for higher persistence rates for large bird carcasses than for small bird and bat carcasses during the rainy season, overall carcass type was not a strong predictor of persistence rates. Similarly, we did not find a strong effect of vegetation type on carcass persistence rates. Results suggest that in order to estimate accurate bird and bat mortality in tropical wind farm areas, seasonality should be incorporated to correction factors of carcass removal rates.

  16. Statistical meandering wake model and its application to yaw-angle optimisation of wind farms

    International Nuclear Information System (INIS)

    Thøgersen, E; Tranberg, B; Greiner, M; Herp, J

    2017-01-01

    The wake produced by a wind turbine is dynamically meandering and of rather narrow nature. Only when looking at large time averages, the wake appears to be static and rather broad, and is then well described by simple engineering models like the Jensen wake model (JWM). We generalise the latter deterministic models to a statistical meandering wake model (SMWM), where a random directional deflection is assigned to a narrow wake in such a way that on average it resembles a broad Jensen wake. In a second step, the model is further generalised to wind-farm level, where the deflections of the multiple wakes are treated as independently and identically distributed random variables. When carefully calibrated to the Nysted wind farm, the ensemble average of the statistical model produces the same wind-direction dependence of the power efficiency as obtained from the standard Jensen model. Upon using the JWM to perform a yaw-angle optimisation of wind-farm power output, we find an optimisation gain of 6.7% for the Nysted wind farm when compared to zero yaw angles and averaged over all wind directions. When applying the obtained JWM-based optimised yaw angles to the SMWM, the ensemble-averaged gain is calculated to be 7.5%. This outcome indicates the possible operational robustness of an optimised yaw control for real-life wind farms. (paper)

  17. Statistical meandering wake model and its application to yaw-angle optimisation of wind farms

    Science.gov (United States)

    Thøgersen, E.; Tranberg, B.; Herp, J.; Greiner, M.

    2017-05-01

    The wake produced by a wind turbine is dynamically meandering and of rather narrow nature. Only when looking at large time averages, the wake appears to be static and rather broad, and is then well described by simple engineering models like the Jensen wake model (JWM). We generalise the latter deterministic models to a statistical meandering wake model (SMWM), where a random directional deflection is assigned to a narrow wake in such a way that on average it resembles a broad Jensen wake. In a second step, the model is further generalised to wind-farm level, where the deflections of the multiple wakes are treated as independently and identically distributed random variables. When carefully calibrated to the Nysted wind farm, the ensemble average of the statistical model produces the same wind-direction dependence of the power efficiency as obtained from the standard Jensen model. Upon using the JWM to perform a yaw-angle optimisation of wind-farm power output, we find an optimisation gain of 6.7% for the Nysted wind farm when compared to zero yaw angles and averaged over all wind directions. When applying the obtained JWM-based optimised yaw angles to the SMWM, the ensemble-averaged gain is calculated to be 7.5%. This outcome indicates the possible operational robustness of an optimised yaw control for real-life wind farms.

  18. High Penetrated Wind Farm Impacts on the Electricity Price

    DEFF Research Database (Denmark)

    Haji Bashi, Mazaher; Yousefi, G. R.; Bak, Claus Leth

    2016-01-01

    of the high penetrated wind farm integration into electricity markets. Then, stochastic programming approach is employed to compare the volume of trades for a typical wind farm in a high and low wind penetrated market. Although increasing price spikes and volatility was reported in the literature......Energy trading policies, intermittency of wind farm output power, low marginal cost of the production, are the key factors that cause the wind farms to be effective on the electricity price. In this paper, the Danish electricity market is studied as a part of Nord Pool. Considering the completely...... fossil fuel free overview in Danish energy policies, and the currently great share of wind power (more than 100% for some hours) in supplying the load, it is an interesting benchmark for the future electricity markets. Negative prices, price spikes, and price volatility are considered as the main effects...

  19. Power Performance Verification of a Wind Farm Using the Friedman’s Test

    Science.gov (United States)

    Hernandez, Wilmar; López-Presa, José Luis; Maldonado-Correa, Jorge L.

    2016-01-01

    In this paper, a method of verification of the power performance of a wind farm is presented. This method is based on the Friedman’s test, which is a nonparametric statistical inference technique, and it uses the information that is collected by the SCADA system from the sensors embedded in the wind turbines in order to carry out the power performance verification of a wind farm. Here, the guaranteed power curve of the wind turbines is used as one more wind turbine of the wind farm under assessment, and a multiple comparison method is used to investigate differences between pairs of wind turbines with respect to their power performance. The proposed method says whether the power performance of the specific wind farm under assessment differs significantly from what would be expected, and it also allows wind farm owners to know whether their wind farm has either a perfect power performance or an acceptable power performance. Finally, the power performance verification of an actual wind farm is carried out. The results of the application of the proposed method showed that the power performance of the specific wind farm under assessment was acceptable. PMID:27271628

  20. Power Performance Verification of a Wind Farm Using the Friedman’s Test

    Directory of Open Access Journals (Sweden)

    Wilmar Hernandez

    2016-06-01

    Full Text Available In this paper, a method of verification of the power performance of a wind farm is presented. This method is based on the Friedman’s test, which is a nonparametric statistical inference technique, and it uses the information that is collected by the SCADA system from the sensors embedded in the wind turbines in order to carry out the power performance verification of a wind farm. Here, the guaranteed power curve of the wind turbines is used as one more wind turbine of the wind farm under assessment, and a multiple comparison method is used to investigate differences between pairs of wind turbines with respect to their power performance. The proposed method says whether the power performance of the specific wind farm under assessment differs significantly from what would be expected, and it also allows wind farm owners to know whether their wind farm has either a perfect power performance or an acceptable power performance. Finally, the power performance verification of an actual wind farm is carried out. The results of the application of the proposed method showed that the power performance of the specific wind farm under assessment was acceptable.

  1. Wind Energy Development in India and a Methodology for Evaluating Performance of Wind Farm Clusters

    Directory of Open Access Journals (Sweden)

    Sanjeev H. Kulkarni

    2016-01-01

    Full Text Available With maturity of advanced technologies and urgent requirement for maintaining a healthy environment with reasonable price, India is moving towards a trend of generating electricity from renewable resources. Wind energy production, with its relatively safer and positive environmental characteristics, has evolved from a marginal activity into a multibillion dollar industry today. Wind energy power plants, also known as wind farms, comprise multiple wind turbines. Though there are several wind-mill clusters producing energy in different geographical locations across the world, evaluating their performance is a complex task and is an important focus for stakeholders. In this work an attempt is made to estimate the performance of wind clusters employing a multicriteria approach. Multiple factors that affect wind farm operations are analyzed by taking experts opinions, and a performance ranking of the wind farms is generated. The weights of the selection criteria are determined by pairwise comparison matrices of the Analytic Hierarchy Process (AHP. The proposed methodology evaluates wind farm performance based on technical, economic, environmental, and sociological indicators. Both qualitative and quantitative parameters were considered. Empirical data were collected through questionnaire from the selected wind farms of Belagavi district in the Indian State of Karnataka. This proposed methodology is a useful tool for cluster analysis.

  2. Comparing satellite SAR and wind farm wake models

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Vincent, P.; Husson, R.

    2015-01-01

    . These extend several tens of kilometres downwind e.g. 70 km. Other SAR wind maps show near-field fine scale details of wake behind rows of turbines. The satellite SAR wind farm wake cases are modelled by different wind farm wake models including the PARK microscale model, the Weather Research and Forecasting...... (WRF) model in high resolution and WRF with coupled microscale parametrization....

  3. Reindeer habitat use in relation to two small wind farms, during preconstruction, construction, and operation.

    Science.gov (United States)

    Skarin, Anna; Alam, Moudud

    2017-06-01

    Worldwide there is a rush toward wind power development and its associated infrastructure. In Fennoscandia, large-scale wind farms comprising several hundred windmills are currently built in important grazing ranges used for Sámi reindeer husbandry. In this study, reindeer habitat use was assessed using reindeer fecal pellet group counts in relation to two relatively small wind farms, with 8 and 10 turbines, respectively. In 2009, 1,315 15-m 2 plots were established and pellet groups were counted and cleaned from the plots. This was repeated once a year in May, during preconstruction, construction, and operation of the wind farms, covering 6 years (2009-2014) of reindeer habitat use in the area. We modeled the presence/absence of any pellets in a plot at both the local (wind farm site) and regional (reindeer calving to autumn range) scale with a hierarchical logistic regression, where spatial correlation was accounted for via random effects, using vegetation type, and the interaction between distance to wind turbine and time period as predictor variables. Our results revealed an absolute reduction in pellet groups by 66% and 86% around each wind farm, respectively, at local scale and by 61% at regional scale during the operation phase compared to the preconstruction phase. At the regional, scale habitat use declined close to the turbines in the same comparison. However, at the local scale, we observed increased habitat use close to the wind turbines at one of the wind farms during the operation phase. This may be explained by continued use of an important migration route close to the wind farm. The reduced use at the regional scale nevertheless suggests that there may be an overall avoidance of both wind farms during operation, but further studies of reindeer movement and behavior are needed to gain a better understanding of the mechanisms behind this suggested avoidance.

  4. Wind Farm Reliability Modelling Using Bayesian Networks and Semi-Markov Processes

    Directory of Open Access Journals (Sweden)

    Robert Adam Sobolewski

    2015-09-01

    Full Text Available Technical reliability plays an important role among factors affecting the power output of a wind farm. The reliability is determined by an internal collection grid topology and reliability of its electrical components, e.g. generators, transformers, cables, switch breakers, protective relays, and busbars. A wind farm reliability’s quantitative measure can be the probability distribution of combinations of operating and failed states of the farm’s wind turbines. The operating state of a wind turbine is its ability to generate power and to transfer it to an external power grid, which means the availability of the wind turbine and other equipment necessary for the power transfer to the external grid. This measure can be used for quantitative analysis of the impact of various wind farm topologies and the reliability of individual farm components on the farm reliability, and for determining the expected farm output power with consideration of the reliability. This knowledge may be useful in an analysis of power generation reliability in power systems. The paper presents probabilistic models that quantify the wind farm reliability taking into account the above-mentioned technical factors. To formulate the reliability models Bayesian networks and semi-Markov processes were used. Using Bayesian networks the wind farm structural reliability was mapped, as well as quantitative characteristics describing equipment reliability. To determine the characteristics semi-Markov processes were used. The paper presents an example calculation of: (i probability distribution of the combination of both operating and failed states of four wind turbines included in the wind farm, and (ii expected wind farm output power with consideration of its reliability.

  5. Parameter study of electric power production in wind farms - experiments using two model scale wind turbines

    OpenAIRE

    Ceccotti, Clio

    2015-01-01

    Wind farms are widely developed even if several unsolved problems need to be faced. The rotor-wake interaction involves different physical phenomena, not yet fully understood, directly affecting the overall wind farm power production. Numerical models and engineering rules have always been used to design wind farm layout but a spread between power predictions and results is verified. In this context wind energy research assumes a "back to basic" approach, by means of wind tunne...

  6. Fault Detection and Load Distribution for the Wind Farm Challenge

    DEFF Research Database (Denmark)

    Borchersen, Anders Bech; Larsen, Jesper Abildgaard; Stoustrup, Jakob

    2014-01-01

    In this paper a fault detection system and a fault tolerant controller for a wind farm model is designed and tested. The wind farm model is taken from the wind farm challenge which is a public available challenge where a wind farm consisting of nine turbines is proposed. The goal of the challenge...... normal and faulty conditions. Thus a fault detection system and a fault tolerant controller has been designed and combined. The fault tolerant control system has then been tested and compared to the reference system and shows improvement on all measures....

  7. Analysis of Anholt offshore wind farm SCADA measurements

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Volker, Patrick; Pena Diaz, Alfredo

    SCADA measurements from the Danish Anholt offshore wind farm (ANH) for a period of 2½ years have been qualified. ANH covers 12 km × 22 km and is located between Djursland and the island Anholt in Kattegat, Denmark. This qualification encompasses identification of curtailment and idling periods......, start/stop events and a power curve control for each wind turbine in the wind farm. Data also include wind speed measurements from a nearby WindCube lidar and simulations from the WRF model for the same period as the SCADA. An equivalent wind speed (wsi) is derived from the combined power and pitch...

  8. Using wind tunnels to predict bird mortality in wind farms: the case of griffon vultures.

    Directory of Open Access Journals (Sweden)

    Manuela de Lucas

    Full Text Available BACKGROUND: Wind farms have shown a spectacular growth during the last 15 years. Avian mortality through collision with moving rotor blades is well-known as one of the main adverse impacts of wind farms. In Spain, the griffon vulture incurs the highest mortality rates in wind farms. METHODOLOGY/PRINCIPAL FINDINGS: As far as we know, this study is the first attempt to predict flight trajectories of birds in order to foresee potentially dangerous areas for wind farm development. We analyse topography and wind flows in relation to flight paths of griffon vultures, using a scaled model of the wind farm area in an aerodynamic wind tunnel, and test the difference between the observed flight paths of griffon vultures and the predominant wind flows. Different wind currents for each wind direction in the aerodynamic model were observed. Simulations of wind flows in a wind tunnel were compared with observed flight paths of griffon vultures. No statistical differences were detected between the observed flight trajectories of griffon vultures and the wind passages observed in our wind tunnel model. A significant correlation was found between dead vultures predicted proportion of vultures crossing those cells according to the aerodynamic model. CONCLUSIONS: Griffon vulture flight routes matched the predominant wind flows in the area (i.e. they followed the routes where less flight effort was needed. We suggest using these kinds of simulations to predict flight paths over complex terrains can inform the location of wind turbines and thereby reduce soaring bird mortality.

  9. Long Term Expected Revenue of Wind Farms Considering the Bidding Admission Uncertainty

    DEFF Research Database (Denmark)

    Bashi, Mazaher Haji; Yousefi, G.R.; Bak, Claus Leth

    2016-01-01

    in the long term expected revenue of wind farms. We show that this consideration could perfectly explain the observed bid shading behavior of wind farm owners. We use a novel market price model with a stochastic model of a wind farm to derive indices describing the uncertainty of bidding admission....... The optimal behavior of the wind farm is then obtained by establishing a multi objective optimization problem and subsequently solved using genetic algorithm. The method is applied to the analysis of long term bidding behavior of a wind farm participating in a Pay-as-Bid (PAB) auction such as Iran Electricity...... Market (IEM). The results demonstrate that wind farm owners change their bid shading behavior in a PAB Auction. However, the expected revenue of the wind farm will also decrease in a PAB auction. As a result, it is not recommended to make an obligation for the wind farms to participate in a PAB auction...

  10. Beauty or Bane: Advancing an Aesthetic Appreciation of Wind Turbine Farms

    Directory of Open Access Journals (Sweden)

    Tyson-Lord J. Gray

    2012-01-01

    Full Text Available I begin this paper by looking at declining wind turbine sales during the years 2007 to 2010. In an attempt to locate a reason for this decline, I evaluate two claims by wind farm opponents: 1 that wind farms reduce property value, and 2 that wind farms ruin the beauty of nature. The first claim I respond to by looking at three studies conducted on residential property sales located near wind farms. For the second claim, I engage in a comparison of Immanuel Kant’s and John Dewey’s aesthetics. I ultimately advance an aesthetic appreciation of wind farms that seeks to view beauty as an integration of both emotional and cognitive perceptions.

  11. Noise impact assessment of wind farms

    International Nuclear Information System (INIS)

    Hayes, M.

    1993-01-01

    The noise impact assessment of a wind farm is dependent upon a number of factors pertinent to the site. The most controversial is the selection of a criterion which is acceptable to both the developer of a site, in terms of maximising the number of turbines he may operate without fear of injunction to stop, and the local residents and Environmental Health Officer who will have to enforce any agreements. A number of British Standards exist which cover noise issues. There are, however, certain reservations about their use when applied to potential wind farm developments; some of the more relevant standards are outlined. In addition, Draft Planning Guidance notes which have recently been issued are discussed. These are intended to provide an indication to local planning authorities as to what noise levels and criteria may be acceptable when considering noise emitted by wind farms. No European standard for noise emission from wind farms exists but the legislative position in Denmark, the Netherlands, Germany and Sweden is briefly considered. It is considered that when a maximum level criterion is set it should take into account the existing background noise levels based on measurements which are taken at the most sensitive dwellings to the site. A method for calculating emitted noise levels from turbine arrays is described. (UK)

  12. Power-flow control and stability enhancement of four parallel-operated offshore wind farms using a line-commutated HVDC link

    DEFF Research Database (Denmark)

    Wang, Li; Wang, Kuo-Hua; Lee, Wei-Jen

    2010-01-01

    This paper presents an effective control scheme using a line-commutated high-voltage direct-current (HVDC) link with a designed rectifier current regulator (RCR) to simultaneously perform both power-fluctuation mitigation and damping improvement of four parallel-operated 80-MW offshore wind farms...... delivering generated power to a large utility grid. The proposed RCR of the HVDC link is designed by using modal control theory to contribute adequate damping to the studied four offshore wind farms under various wind speeds. A systematic analysis using a frequency-domain approach based on eigenvalue...... characteristics to the studied offshore wind farms under various wind speeds but also effectively mitigate power fluctuations of the offshore wind farms under wind-speed disturbance conditions....

  13. 3. International Workshop on Transmission Networks for Offshore Wind Farms. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, T [ed.

    2002-07-01

    The emphasis is on both theoretical discussions and on practical applications. After almost a decade with mainly demonstration projects in the area of offshore wind power, this year will see the first large commercial offshore wind projects with more than 50 MW installed capacity and more and more larger projects are scheduled for the coming years. Also more and more energy policy makers, electric utilities as well as the media recognize the enormous potential of offshore wind power as a large-scale sustainable energy source. The development in this area results in new ideas, questions and research proposals. Such a new topic is, hydrogen production using offshore wind farms.

  14. Avoidance of wind farms by harbour seals is limited to pile driving activities.

    Science.gov (United States)

    Russell, Debbie J F; Hastie, Gordon D; Thompson, David; Janik, Vincent M; Hammond, Philip S; Scott-Hayward, Lindesay A S; Matthiopoulos, Jason; Jones, Esther L; McConnell, Bernie J

    2016-12-01

    As part of global efforts to reduce dependence on carbon-based energy sources there has been a rapid increase in the installation of renewable energy devices. The installation and operation of these devices can result in conflicts with wildlife. In the marine environment, mammals may avoid wind farms that are under construction or operating. Such avoidance may lead to more time spent travelling or displacement from key habitats. A paucity of data on at-sea movements of marine mammals around wind farms limits our understanding of the nature of their potential impacts.Here, we present the results of a telemetry study on harbour seals Phoca vitulina in The Wash, south-east England, an area where wind farms are being constructed using impact pile driving. We investigated whether seals avoid wind farms during operation, construction in its entirety, or during piling activity. The study was carried out using historical telemetry data collected prior to any wind farm development and telemetry data collected in 2012 during the construction of one wind farm and the operation of another.Within an operational wind farm, there was a close-to-significant increase in seal usage compared to prior to wind farm development. However, the wind farm was at the edge of a large area of increased usage, so the presence of the wind farm was unlikely to be the cause.There was no significant displacement during construction as a whole. However, during piling, seal usage (abundance) was significantly reduced up to 25 km from the piling activity; within 25 km of the centre of the wind farm, there was a 19 to 83% (95% confidence intervals) decrease in usage compared to during breaks in piling, equating to a mean estimated displacement of 440 individuals. This amounts to significant displacement starting from predicted received levels of between 166 and 178 dB re 1 μPa (p-p) . Displacement was limited to piling activity; within 2 h of cessation of pile driving, seals were distributed as

  15. Underwater acoustic characteristics of the OWEZ wind farm operation (T1)

    NARCIS (Netherlands)

    Haan, de D.; Burggraaf, D.; Wal, van der J.T.; Hal, van R.

    2013-01-01

    In Holland the first two offshore wind farms, the Offshore Wind Farm Egmond aan Zee (OWEZ) and “Prinses Amalia” were built in respectively 2006 and 2007. Beside the main goal of producing electric energy from wind resource the construction of the first wind farm (OWEZ) was also used to demonstrate

  16. Optimization of Wind Farm Layout: A Refinement Method by Random Search

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2013-01-01

    Wind farm layout optimization is to find the optimal positions of wind turbines inside a wind farm, so as to maximize and/or minimize a single objective or multiple objectives, while satisfying certain constraints. Most of the works in the literature divide the wind farm into cells in which turbi...

  17. Preliminary manual of the wind farms impacts study

    International Nuclear Information System (INIS)

    2000-11-01

    This document aims to present and propose tools and methods allowing the improve the environmental quality of the future wind farms projects. After a presentation of general notions on the wind farms and the economy of the wind energy, it presents the regulation and the procedures concerning the environmental impact. It proposes then the main possible effects and the impacts study themes. (A.L.B.)

  18. Comparative study of the behavior of wind-turbines in a wind farm

    Energy Technology Data Exchange (ETDEWEB)

    Migoya, Emilio; Crespo, Antonio; Garcia, Javier; Manuel, Fernando; Jimenez, Angel [Universidad Politecnica de Madrid (UPM), Madrid (Spain). Departamento de Ingenieria Energetica y Fluidomecanica, Laboratorio de Mecanica de Fluidos; Moreno, Fermin [Comision Nacional de la Energia, Madrid (Spain); Costa, Alexandre [Energia Eolica, Division de Energias Renovables, CIEMAT, Madrid (Spain)

    2007-10-15

    The Sotavento wind farm is an experimental wind farm which has different types of wind turbines. It is located in an area whose topography is moderately complex, and where wake effects can be significant. One of the objectives of Sotavento wind farm is to compare the performances of the different machines; particularly regarding power production, maintenance and failures. However, because of wakes and topography, the different machines are not working under identical conditions. Two linearized codes have been used to estimate topography effects: UPMORO and WAsP. For wind directions in which topography is abrupt, the non-linear flow equations have been solved with the commercial code FLUENT, although the results are only qualitatively used. For wake effects, the UPMPARK code has been applied. As a result, the incident velocity over each wind turbine is obtained, and the power production is estimated by means of the power curve of each machine. Experimental measurements give simultaneously the wind characteristics at the measuring stations, the wind velocity, at the nacelle anemometer, and the power production of each wind turbine. These experimental results are employed to validate the numerical predictions. The main objective of this work is to deduce and validate a relationship between the wind characteristics measured in the anemometers and the wind velocity and the power output in each machine. (author)

  19. Comparative evaluation of different offshore wind turbine installation vessels for Korean west–south wind farm

    Directory of Open Access Journals (Sweden)

    Dang Ahn

    2017-01-01

    Full Text Available The purpose of this study is to evaluate various means of wind power turbines installation in the Korean west–south wind farm (Test bed 100 MW, Demonstrate site 400 MW. We presented the marine environment of the southwest offshore wind farm in order to decide the appropriate installation vessel to be used in this site. The various vessels would be WTIV (Wind turbine installation vessel, jack-up barge, or floating crane … etc. We analyzed the installation cost of offshore wind turbine and the transportation duration for each vessel. The analysis results showed the most suitable installation means for offshore wind turbine in the Korean west–south wind farm.

  20. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2013-01-01

    In the recent years the wind turbine industry has focused on optimizing the cost of energy. One of the important factors in this is to increase reliability of the wind turbines. Advanced fault detection, isolation and accommodation are important tools in this process. Clearly most faults are deal...... scenarios. This benchmark model is used in an international competition dealing with Wind Farm fault detection and isolation and fault tolerant control....

  1. Gradient-Based Optimization of Wind Farms with Different Turbine Heights: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, Andrew P. J.; Thomas, Jared; Ning, Andrew; Annoni, Jennifer; Dykes, Katherine; Fleming, Paul

    2017-05-08

    Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5%-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and a low wind shear exponent.

  2. Wind farms providing secondary frequency regulation: Evaluating the performance of model-based receding horizon control

    International Nuclear Information System (INIS)

    Shapiro, Carl R.; Meneveau, Charles; Gayme, Dennice F.; Meyers, Johan

    2016-01-01

    We investigate the use of wind farms to provide secondary frequency regulation for a power grid. Our approach uses model-based receding horizon control of a wind farm that is tested using a large eddy simulation (LES) framework. In order to enable real-time implementation, the control actions are computed based on a time-varying one-dimensional wake model. This model describes wake advection and interactions, both of which play an important role in wind farm power production. This controller is implemented in an LES model of an 84-turbine wind farm represented by actuator disk turbine models. Differences between the velocities at each turbine predicted by the wake model and measured in LES are used for closed-loop feedback. The controller is tested on two types of regulation signals, “RegA” and “RegD”, obtained from PJM, an independent system operator in the eastern United States. Composite performance scores, which are used by PJM to qualify plants for regulation, are used to evaluate the performance of the controlled wind farm. Our results demonstrate that the controlled wind farm consistently performs well, passing the qualification threshold for all fastacting RegD signals. For the RegA signal, which changes over slower time scales, the controlled wind farm's average performance surpasses the threshold, but further work is needed to enable the controlled system to achieve qualifying performance all of the time. (paper)

  3. Fast simulation approaches for power fluctuation model of wind farm based on frequency domain

    DEFF Research Database (Denmark)

    Lin, Jin; Gao, Wen-zhong; Sun, Yuan-zhang

    2012-01-01

    This paper discusses one model developed by Riso, DTU, which is capable of simulating the power fluctuation of large wind farms in frequency domain. In the original design, the “frequency-time” transformations are time-consuming and might limit the computation speed for a wind farm of large size....... Under this background, this paper proposes four efficient approaches to accelerate the simulation speed. Two of them are based on physical model simplifications, and the other two improve the numerical computation. The case study demonstrates the efficiency of these approaches. The acceleration ratio...... is more than 300 times if all these approaches are adopted, in any low, medium and high wind speed test scenarios....

  4. Complete wind farm electromagnetic transient modelling for grid integration studies

    International Nuclear Information System (INIS)

    Zubia, I.; Ostolaza, X.; Susperregui, A.; Tapia, G.

    2009-01-01

    This paper presents a modelling methodology to analyse the impact of wind farms in surrounding networks. Based on the transient modelling of the asynchronous generator, the multi-machine model of a wind farm composed of N generators is developed. The model incorporates step-up power transformers, distribution lines and surrounding loads up to their connection to the power network. This model allows the simulation of symmetric and asymmetric short-circuits located in the distribution network and the analysis of transient stability of wind farms. It can be also used to study the islanding operation of wind farms

  5. Potential climatic impacts and reliability of large-scale offshore wind farms

    International Nuclear Information System (INIS)

    Wang Chien; Prinn, Ronald G

    2011-01-01

    The vast availability of wind power has fueled substantial interest in this renewable energy source as a potential near-zero greenhouse gas emission technology for meeting future world energy needs while addressing the climate change issue. However, in order to provide even a fraction of the estimated future energy needs, a large-scale deployment of wind turbines (several million) is required. The consequent environmental impacts, and the inherent reliability of such a large-scale usage of intermittent wind power would have to be carefully assessed, in addition to the need to lower the high current unit wind power costs. Our previous study (Wang and Prinn 2010 Atmos. Chem. Phys. 10 2053) using a three-dimensional climate model suggested that a large deployment of wind turbines over land to meet about 10% of predicted world energy needs in 2100 could lead to a significant temperature increase in the lower atmosphere over the installed regions. A global-scale perturbation to the general circulation patterns as well as to the cloud and precipitation distribution was also predicted. In the later study reported here, we conducted a set of six additional model simulations using an improved climate model to further address the potential environmental and intermittency issues of large-scale deployment of offshore wind turbines for differing installation areas and spatial densities. In contrast to the previous land installation results, the offshore wind turbine installations are found to cause a surface cooling over the installed offshore regions. This cooling is due principally to the enhanced latent heat flux from the sea surface to lower atmosphere, driven by an increase in turbulent mixing caused by the wind turbines which was not entirely offset by the concurrent reduction of mean wind kinetic energy. We found that the perturbation of the large-scale deployment of offshore wind turbines to the global climate is relatively small compared to the case of land

  6. Impacts of Wind Farms on Cumulus Cloud Development in the Central Great Plains

    Science.gov (United States)

    Mahoney, L. C.; Wagner, T. J.; L'Ecuyer, T. S.; Kulie, M.

    2014-12-01

    Cumulus clouds have a net cooling effect on the surface radiative balance by reflecting more downwelling solar radiation than absorbing upwelling terrestrial radiation. As boundary layer cumuli form from buoyant, moist plumes ascending from the surface, their growth may be hindered by the turbulent deformation of the plume by wind farms. A natural laboratory to study the impact of wind farms on cumulus formation are the states of Iowa and Nebraska. Despite their prime location for wind resources and similar synoptic forcings, regulatory issues cause these two states to vary vastly in their wind power offerings. In 2013, Iowa ranked 3rd in the nation for total megawatts installed and generates over a quarter of its electricity from wind energy, more than any other state. In contrast, Nebraska has an order of magnitude fewer turbines installed, and less than five percent of the state's electrical load is wind-generated. This variance in wind power in close proximity makes Iowa and Nebraska a prime area for initial research. This study uses Geostationary Operational Environmental Satellite (GOES) visible satellite imagery from the summer of 2009 to 2013 to investigate cumulus development in these adjacent states, as the majority of large-scale wind farms in Iowa were completed by 2009. Image reflectances in Nebraska and Iowa are compared to determine the magnitude of cumulus growth. Preliminary analysis indicates a reduction in cumulus development near the existing wind farms; a synoptic investigation of these cases will be completed to determine causality.

  7. Microplastics in a wind farm area: A case study at the Rudong Offshore Wind Farm, Yellow Sea, China.

    Science.gov (United States)

    Wang, Teng; Zou, Xinqing; Li, Baojie; Yao, Yulong; Li, Jiasheng; Hui, Hejiu; Yu, Wenwen; Wang, Chenglong

    2018-03-01

    Despite the rapid construction of offshore wind farms, the available information regarding the risks of this type of development in terms of emerging pollutants, particularly microplastics, is scarce. In this study, we quantified the level of microplastic pollution at an offshore wind farm in the Yellow Sea, China, in 2016. The abundance of microplastics was 0.330 ± 0.278 items/m 3 in the surface water and 2.58 ± 1.14 items/g (dry) in the sediment. To the best of our knowledge, the level of microplastic pollution in our study area was slightly higher than that in coastal areas around the world. The microplastics detected in the surface waters and sediments were mainly fibrous (75.3% and 68.7%, respectively) and consisted of some granules and films. The microplastics in the samples might originate from garments or ropes via wastewater discharge. The abundance of plastic in the water and sediment samples collected from the wind farm area was lower than that in the samples collected from outside the wind farm area. The anthropogenic hydrodynamic effect was the main factor affecting the local distribution of microplastics. The presence of a wind farm could increase the bed shear stress during ebb tide, disturbing the bed sediment, facilitating its initiation and transport, and ultimately increasing the ease of washing away the microplastics adhered to the sediment. This study will serve as a reference for further studies of the distribution and migration of microplastics in coastal zones subjected to similar marine utilization. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Beauty or Bane: Advancing an Aesthetic Appreciation of Wind Turbine Farms

    OpenAIRE

    Tyson-Lord J. Gray

    2012-01-01

    I begin this paper by looking at declining wind turbine sales during the years 2007 to 2010. In an attempt to locate a reason for this decline, I evaluate two claims by wind farm opponents: 1) that wind farms reduce property value, and 2) that wind farms ruin the beauty of nature. The first claim I respond to by looking at three studies conducted on residential property sales located near wind farms. For the second claim, I engage in a comparison of Immanuel Kant’s and John Dewey’s aesthet...

  9. Wind farms in hostile terrain

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    This report summarises the results of a study aimed at reducing risks associated with wind farms in hostile conditions, evaluating and refining design procedures for such sites, and reviewing the results in terms of the current design practice. The scientific and technical background to the study is described, and measurements taken at two hostile sites in the UK and Italy, the wind data, wind turbine loads, the impact of icing, and wind turbine design for hostile conditions are examined, and actual and planned activities are compared.

  10. Guest Editorial Modeling and Advanced Control of Wind Turbines/Wind Farms

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J.; Hou, Y.; Zhu, Z.; Xu, D.; Xu, D.; Muljadi, E.; Liu, F.; Iwanski, G.; Geng, H.; Erlich, I.; Wen, J.; Harnefors, L.; Fan, L.; El Moursi, M. S.; Kjaer, P. C.; Nelson, R. J.; Cardenas, R.; Feng, S.; Islam, S.; Qiao, W.; Yuan, X.

    2017-09-01

    The papers in this special section brings together papers focused on the recent advancements and breakthroughs in the technology of modeling and enhanced active/reactive power control of wind power conversion systems, ranging from components of wind turbines to wind farms.

  11. Optimal siting and sizing of wind farms

    NARCIS (Netherlands)

    Cetinay-Iyicil, H.; Kuipers, F.A.; Guven, A. Nezih

    2017-01-01

    In this paper, we propose a novel technique to determine the optimal placement of wind farms, thereby taking into account wind characteristics and electrical grid constraints. We model the long-term variability of wind speed using a Weibull distribution according to wind direction intervals, and

  12. Dynamic Federalism and Wind Farm Siting

    Science.gov (United States)

    2014-05-18

    shining through the rotating blades. The turbines can interfere with 19 television and radio reception. Wind farms are known to kill birds and bats...Id. at 332.20 NAT’L WIND COORDINATING COLLABORATIVE, WIND TURBINE INTERACTIONS WITH 21 BIRDS , BATS, AND THEIR HABITATS: A SUMMARY OF RESEARCH...drawbacks, however. Among these, the mechanical and electromagnetic properties of wind turbines pose significant hazards and complications to U.S

  13. Simulation of interaction between wind farm and power system

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Hansen, Anca Daniela; Janosi, L.

    2002-01-01

    A dynamic model of the wind farm Hagesholm has been implemented in the dedicated power system simulation program DIgSILENT. The wind farm con- sists of six 2MW NM2000/72 wind turbines from NEG-Micon. The model has been verified using simultaneous powerquality measurements on the 10 kV terminals...

  14. Multi-objective genetic algorithm based innovative wind farm layout optimization method

    International Nuclear Information System (INIS)

    Chen, Ying; Li, Hua; He, Bang; Wang, Pengcheng; Jin, Kai

    2015-01-01

    Highlights: • Innovative optimization procedures for both regular and irregular shape wind farm. • Using real wind condition and commercial wind turbine parameters. • Using multiple-objective genetic algorithm optimization method. • Optimize the selection of different wind turbine types and their hub heights. - Abstract: Layout optimization has become one of the critical approaches to increase power output and decrease total cost of a wind farm. Previous researches have applied intelligent algorithms to optimizing the wind farm layout. However, those wind conditions used in most of previous research are simplified and not accurate enough to match the real world wind conditions. In this paper, the authors propose an innovative optimization method based on multi-objective genetic algorithm, and test it with real wind condition and commercial wind turbine parameters. Four case studies are conducted to investigate the number of wind turbines needed in the given wind farm. Different cost models are also considered in the case studies. The results clearly demonstrate that the new method is able to optimize the layout of a given wind farm with real commercial data and wind conditions in both regular and irregular shapes, and achieve a better result by selecting different type and hub height wind turbines.

  15. The pattern of complaints about Australian wind farms does not match the establishment and distribution of turbines: support for the psychogenic, 'communicated disease' hypothesis.

    Science.gov (United States)

    Chapman, Simon; St George, Alexis; Waller, Karen; Cakic, Vince

    2013-01-01

    With often florid allegations about health problems arising from wind turbine exposure now widespread, nocebo effects potentially confound any future investigation of turbine health impact. Historical audits of health complaints are therefore important. We test 4 hypotheses relevant to psychogenic explanations of the variable timing and distribution of health and noise complaints about wind farms in Australia. All Australian wind farms (51 with 1634 turbines) operating 1993-2012. Records of complaints about noise or health from residents living near 51 Australian wind farms were obtained from all wind farm companies, and corroborated with complaints in submissions to 3 government public enquiries and news media records and court affidavits. These are expressed as proportions of estimated populations residing within 5 km of wind farms. There are large historical and geographical variations in wind farm complaints. 33/51 (64.7%) of Australian wind farms including 18/34 (52.9%) with turbine size >1 MW have never been subject to noise or health complaints. These 33 farms have an estimated 21,633 residents within 5 km and have operated complaint-free for a cumulative 267 years. Western Australia and Tasmania have seen no complaints. 129 individuals across Australia (1 in 254 residents) appear to have ever complained, with 94 (73%) being residents near 6 wind farms targeted by anti wind farm groups. The large majority 116/129(90%) of complainants made their first complaint after 2009 when anti wind farm groups began to add health concerns to their wider opposition. In the preceding years, health or noise complaints were rare despite large and small-turbine wind farms having operated for many years. The reported historical and geographical variations in complaints are consistent with psychogenic hypotheses that expressed health problems are "communicated diseases" with nocebo effects likely to play an important role in the aetiology of complaints.

  16. A comprehensive atlas of wind farms in France

    International Nuclear Information System (INIS)

    Ducuing, S.; Guillier, A.; Guichard, M.A.

    2015-01-01

    This article reports all the wind farms that have been carried out or are in project in France at the date of may 2015. All these installations represent an installed capacity of 13.817 MW including 3.524 MW that are in project (they are expected to enter into service during the next 3 years) and 434 MW that have been carried out during the first 5 months of 2015. A total of 1148 wind farms are reported. For each wind farm the following information is given: the name of the operator, the power output, the number of turbines, the name of the turbine manufacturer and the commissioning date. (A.C.)

  17. Numerical investigation of interactions between marine atmospheric boundary layer and offshore wind farm

    Science.gov (United States)

    Lyu, Pin; Chen, Wenli; Li, Hui; Shen, Lian

    2017-11-01

    In recent studies, Yang, Meneveau & Shen (Physics of Fluids, 2014; Renewable Energy, 2014) developed a hybrid numerical framework for simulation of offshore wind farm. The framework consists of simulation of nonlinear surface waves using a high-order spectral method, large-eddy simulation of wind turbulence on a wave-surface-fitted curvilinear grid, and an actuator disk model for wind turbines. In the present study, several more precise wind turbine models, including the actuator line model, actuator disk model with rotation, and nacelle model, are introduced into the computation. Besides offshore wind turbines on fixed piles, the new computational framework has the capability to investigate the interaction among wind, waves, and floating wind turbines. In this study, onshore, offshore fixed pile, and offshore floating wind farms are compared in terms of flow field statistics and wind turbine power extraction rate. The authors gratefully acknowledge financial support from China Scholarship Council (No. 201606120186) and the Institute on the Environment of University of Minnesota.

  18. Site selection for offshore wind farms along the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    ManiMurali, R.; Vidya, P.J.; Modi, P.; JayaKumar, S.

    This study deals with locating the potential sites for offshore wind farms and also deals with feasibility of installing offshore wind farms through scientific examination of the requirements along the coast of India Offshore wind energy is almost...

  19. Great expectations: large wind turbines

    International Nuclear Information System (INIS)

    De Vries, E.

    2001-01-01

    This article focuses on wind turbine product development, and traces the background to wind turbines from the first generation 1.5 MW machines in 1995-6, plans for the second generation 3-5 MW class turbines to meet the expected boom in offshore wind projects, to the anticipated installation of a 4.5 MW turbine, and offshore wind projects planned for 2000-2002. The switch by the market leader Vestas to variable speed operation in 2000, the new product development and marketing strategy taken by the German Pro + Pro consultancy in their design of a 1.5 MW variable speed pitch control concept, the possible limiting of the size of turbines due to logistical difficulties, opportunities offered by air ships for large turbines, and the commissioning of offshore wind farms are discussed. Details of some 2-5 MW offshore wind turbine design specifications are tabulated

  20. Shadowing effects of offshore wind farms - an idealised mesoscale model study

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    The study of wind farm (WF) interaction is expected to gain importance, since the offshore wind farm density will increase especially in the North Sea in the near future. We present preliminary results of wind farm interaction simulated by mesoscale models. We use the Explicit Wake Parametrisatio...

  1. Small signal modeling of wind farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2017-01-01

    -Input Multi-Output (MIMO) dynamic system, where the current control loops with Phase-Locked Loops (PLLs) are linearized around an operating point. Each sub-module of the wind farm is modeled as a 2×2 admittance matrix in dq-domain and all are combined together by using a dq nodal admittance matrix....... The frequency and damping of the oscillatory modes are calculated by finding the poles of the introduced MIMO matrix. Time-domain simulation results obtained from a 400-MW wind farm are used to verify the effectiveness of the presented model....

  2. Financial structures for wind farms

    International Nuclear Information System (INIS)

    Johns, J.H.

    1994-01-01

    This paper provides a summary of the structures used to finance wind farms. It takes into account the impact of the 3rd tranche of the NFFO and provides an evaluation of cash returns using Ernst and Young's wind energy model. Suggestions for further developments in financing include the use of specialist financial instruments and tax planning techniques. (author)

  3. Review of grid code frequency requirements for wind farms

    Energy Technology Data Exchange (ETDEWEB)

    El Itani, S.; Joos, G. [McGill Univ., Montreal, PQ (Canada)

    2010-07-01

    This paper presented frequency grid code requirements for the connection of wind farms to power systems at the high voltage level. The necessity of ensuring that connected wind farms will contribute to the secure operation of the power system in a manner similar to conventional generators has led to the development of several grid code requirements (GCRs) for the integration of wind farms to the grid. These provisions are in place to ensure that wind projects do not negatively impact system stability and reliability. A comparative overview of the main requirements was conducted, looking at national and regional codes from areas with high wind penetration levels. These requirements provide wind farms with the control and regulation capabilities encountered in conventional power plants, which is necessary for the safe, reliable, and economic operation of the system. These requirements have heavily influenced the development of wind turbine generator (WTGs) technology over the last decade. It was concluded that modern WTGs are capable of meeting all the requirements thus far set for active power and ramp rates, extended frequency range, and frequency response required for functional incorporation into modern power grids. 17 refs., 6 tabs., 11 figs.

  4. Effects of the Horns Reef wind farm on harbour porpoises

    International Nuclear Information System (INIS)

    Tougaard, J.; Teilmann, J.; Rye Hansen, J.

    2004-09-01

    Horns Reef offshore wind farm was established in 2002. It consists of 80 2 MW wind turbines, mounted on steel monopile foundations. A harbour porpoise monitoring program was set up in connection with the environmental impact assessment (EIA) of the wind farm project. This monitoring program started in 1999 with collection of baseline data and has continued though construction and operational period. The program continues through 2005. Baseline studies showed that harbour porpoises are abundant in the area, including the area where the wind farm is now located. Significant effects on behaviour and distribution of the porpoises were observed during the construction of the wind farm. Changes could be linked to pile driving operations, where monopile foundations were rammed into the seabed. This procedure produced high levels of underwater noise and mitigation procedures in the form of a ramp up procedure and deployment of acoustic alarms were employed. During the construction period very few animals were observed inside the wind farm area. Acoustic monitoring data showed a significant increase in waiting time between porpoise encounters in connection with pile driving operations, followed by a rapid return to levels normal for the construction period as a whole. However, when the entire construction period was considered as a whole, T-POD activity increased relative to baseline. Observations during operation of the wind farm in 2003 showed a return to baseline levels on most of the indicators derived from the acoustic monitoring and animals were again seen inside the wind farm area. (au)

  5. Optimal Coordinated Control of Power Extraction in LES of a Wind Farm with Entrance Effects

    Directory of Open Access Journals (Sweden)

    Jay P. Goit

    2016-01-01

    Full Text Available We investigate the use of optimal coordinated control techniques in large eddy simulations of wind farm boundary layer interaction with the aim of increasing the total energy extraction in wind farms. The individual wind turbines are considered as flow actuators, and their energy extraction is dynamically regulated in time, so as to optimally influence the flow field. We extend earlier work on wind farm optimal control in the fully-developed regime (Goit and Meyers 2015, J. Fluid Mech. 768, 5–50 to a ‘finite’ wind farm case, in which entrance effects play an important role. For the optimal control, a receding horizon framework is employed in which turbine thrust coefficients are optimized in time and per turbine. Optimization is performed with a conjugate gradient method, where gradients of the cost functional are obtained using adjoint large eddy simulations. Overall, the energy extraction is increased 7% by the optimal control. This increase in energy extraction is related to faster wake recovery throughout the farm. For the first row of turbines, the optimal control increases turbulence levels and Reynolds stresses in the wake, leading to better wake mixing and an inflow velocity for the second row that is significantly higher than in the uncontrolled case. For downstream rows, the optimal control mainly enhances the sideways mean transport of momentum. This is different from earlier observations by Goit and Meyers (2015 in the fully-developed regime, where mainly vertical transport was enhanced.

  6. Sequential Convex Programming for Power Set-point Optimization in a Wind Farm using Black-box Models, Simple Turbine Interactions, and Integer Variables

    DEFF Research Database (Denmark)

    Hovgaard, Tobias Gybel; Larsen, Lars F. S.; Jørgensen, John Bagterp

    2012-01-01

    We consider the optimization of power set-points to a large number of wind turbines arranged within close vicinity of each other in a wind farm. The goal is to maximize the total electric power extracted from the wind, taking the wake effects that couple the individual turbines in the farm into a...... is far superior to, a more naive distribution scheme. We employ a fast convex quadratic programming solver to carry out the iterations in the range of microseconds for even large wind farms....

  7. Probabilistic Capacity of a Grid connected Wind Farm

    DEFF Research Database (Denmark)

    Zhao, Menghua; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    This paper proposes a method to find the maximum acceptable wind power injection regarding the thermal limits, steady state stability limits and voltage limits of the grid system. The probabilistic wind power is introduced based on the probability distribution of wind speed. Based on Power Transfer...... Distribution Factor (PTDF) and voltage sensitivities, a predictor-corrector method is suggested to calculate the acceptable active power injection. Then this method is combined with the probabilistic model of wind power to compute the allowable capacity of the wind farm. Finally, an example is illustrated...... to test this method. It is concluded that proposed method in this paper is a feasible, fast, and accurate approach to find the size of a wind farm....

  8. Forecasting wind power production from a wind farm using the RAMS model

    DEFF Research Database (Denmark)

    Tiriolo, L.; Torcasio, R. C.; Montesanti, S.

    2015-01-01

    of the ECMWF Integrated Forecasting System (IFS), whose horizontal resolution over Central Italy is about 25 km at the time considered in this paper. Because wind observations were not available for the site, the power curve for the whole wind farm was derived from the ECMWF wind operational analyses available......The importance of wind power forecast is commonly recognized because it represents a useful tool for grid integration and facilitates the energy trading. This work considers an example of power forecast for a wind farm in the Apennines in Central Italy. The orography around the site is complex...... and the horizontal resolution of the wind forecast has an important role. To explore this point we compared the performance of two 48 h wind power forecasts using the winds predicted by the Regional Atmospheric Modeling System (RAMS) for the year 2011. The two forecasts differ only for the horizontal resolution...

  9. Peigan Nation to start 101 MW wind farm this month

    International Nuclear Information System (INIS)

    McArthur, D.; Salaff, S.

    1998-01-01

    A joint venture, named Weather-Dancer Wind Power Inc., between Advanced Thermodynamics Corporation (ATC) and the Peigan First Nation Community in Alberta will begin construction in June of a wind farm on its 39,000 hectare reserve. The construction will be progressive, up to a maximum of 101 MW. If and when the farm reaches its full size, it will have cost around $175 million. The wind farm will utilize Nordex Balcke-Duerr (Nordex BD) wind turbines from Denmark. ATC is the sole distributor of these turbines in Canada, and will seek opportunities to market Nordex BD turbines and components throughout Alberta and Western Canada. ATC is also aggressively pursuing opportunities in Quebec and in Atlantic Canada. Financing for the construction of the wind farm and a long-term power purchase and distribution agreement with TransAlta Utilities are as yet incomplete, but negotiations are reported to be progressing well. The Nordex BD N54/1000, rated at one MW, will be the largest turbine, and the Peigan Nation Farm the largest wind farm in North America. This is the second attempt by the Peigan Nation to develop a wind farm on the reserve. On the first attempt, the development failed to secure access to the land needed for the project. This time around, a referendum will be held well in advance of the starting date for construction to obtain majority band approval of the site

  10. A Novel Energy Yields Calculation Method for Irregular Wind Farm Layout

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Soltani, Mohsen

    2015-01-01

    Due to the increasing size of offshore wind farm, the impact of the wake effect on energy yields become more and more evident. The Seafloor topography would limit the layout of the wind farm so that irregular layout is usually adopted inlarge scale offshore wind farm. However, the calculation...

  11. Simulation of wake effects between two wind farms

    International Nuclear Information System (INIS)

    Hansen, K S; Réthoré, P-E; Peña, A; Ott, S; Van der Laan, M P; Volker, P; Palma, J; Hevia, B G; Prospathopoulos, J; Schepers, G; Palomares, A

    2015-01-01

    SCADA data, recorded on the downstream wind farm, has been used to identify flow cases with visible clustering effects. The inflow condition is derived from a partly undisturbed wind turbine, due to lack of mast measurements. The SCADA data analysis concludes that centre of the deficit for the downstream wind farm with disturbed inflow has a distinct visible maximum deficit zone located only 5-10D downstream from the entrance. This zone, representing 20-30% speed reduction, increases and moves downstream for increasing cluster effect and is not visible outside a flow sector of 20-30°. The eight flow models represented in this benchmark include both RANS models, mesoscale models and engineering models. The flow cases, identified according to the wind speed level and inflow sector, have been simulated and validated with the SCADA results. The model validation concludes that all models more or less are able to predict the location and size of the deficit zone inside the downwind wind farm. (paper)

  12. InfraSound from wind turbines : observations from Castle River wind farm. Volume 1

    International Nuclear Information System (INIS)

    Edworthy, J.; Hepburn, H.

    2005-01-01

    Although infrasound has been discussed as a concern by groups opposed to wind farm facilities, there is very little information available about infrasound and wind turbines. This paper presented details of a project conducted by VisionQuest, the largest wind power producer in Canada. Three sensor types were used: precision sound analyzer, seismic geophones, and calibrated microphones to take measurements in low, medium and high winds. The project also measured infrasound when the wind farm was not operating. Acquisition geometry was presented, as well as details of apparent attenuations of wind noise. It was noted that high wind noise was a dominant factor and that there was little difference when the wind farm was not operational. It was suggested that turbines have no impact with high wind, since wind noise is not attenuated with distance. It was noted that increased geophone amplitudes indicate high wind coupled motion which is attenuated when the turbines are on. Results indicate that all frequencies showed attenuation with distance. Evidence showed that low frequency sound pressure levels were often lower when the turbines were switched on. Where turbines contributed to sound pressure levels, the magnitude of the contribution was below levels of concern to human health. Ambient sound pressure levels were much higher than contributions from wind turbines. It was concluded that wind itself generates infrasound. Wind turbines generate low levels of infrasound, detectable very close to facilities at low to medium wind speeds. Wind turbines may reduce ambient infrasound levels at high wind speeds by converting the energy from the wind into electricity. refs., tabs., figs

  13. A preliminary benefit-cost study of a Sandia wind farm.

    Energy Technology Data Exchange (ETDEWEB)

    Ehlen, Mark Andrew; Griffin, Taylor; Loose, Verne W.

    2011-03-01

    In response to federal mandates and incentives for renewable energy, Sandia National Laboratories conducted a feasibility study of installing an on-site wind farm on Sandia National Laboratories and Kirtland Air Force Base property. This report describes this preliminary analysis of the costs and benefits of installing and operating a 15-turbine, 30-MW-capacity wind farm that delivers an estimated 16 percent of 2010 onsite demand. The report first describes market and non-market economic costs and benefits associated with operating a wind farm, and then uses a standard life-cycle costing and benefit-cost framework to estimate the costs and benefits of a wind farm. Based on these 'best-estimates' of costs and benefits and on factor, uncertainty and sensitivity analysis, the analysis results suggest that the benefits of a Sandia wind farm are greater than its costs. The analysis techniques used herein are applicable to the economic assessment of most if not all forms of renewable energy.

  14. Wind farm turbulence impacts on general aviation airports in Kansas.

    Science.gov (United States)

    2014-01-01

    Wind turbines and wind farms have become popular in the State of Kansas. Some general aviation pilots have expressed a concern about the : turbulence that the spinning blades are creating. If a wind farm is built near an airport, does this affect the...

  15. In-operation learning of optimal wind farm operation strategy

    OpenAIRE

    Oliva Gratacós, Joan

    2017-01-01

    In a wind farm, power losses due to wind turbine wake effects can be up to 30-40% under certain conditions. As the global installed wind power capacity increases, the mitigation of wake effects in wind farms is gaining more importance. Following a conventional control strategy, each individual turbine maximizes its own power production without taking into consideration its effects on the performance of downstream turbines. Therefore, this control scheme results in operation con...

  16. Global experience curves for wind farms

    International Nuclear Information System (INIS)

    Junginger, M.; Faaij, A.; Turkenburg, W.C.

    2005-01-01

    In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline

  17. Are wind farms set to become the next dotcom bubble?

    International Nuclear Information System (INIS)

    Desbarres, A.

    2008-01-01

    In the current context of soaring turbine prices, supply bottlenecks and record wind farm valuations, carefully crafted entry strategies are key to growing profitable and competitive wind portfolios. The wind energy industry is growing rapidly on the back of technological advancements, political will and government subsidies. Utility companies, independent power providers, institutional investors and oil companies are all seeking to capitalise on lucrative support mechanisms to unlock greater commercial and competitive advantages, meet their renewables targets and boost their green credentials. Strong growth therefore continues on the back of record sustainable energy investments, yet record wind-farm development costs and valuations are now driving 'dotcom' comparisons as the economics of wind farming projects come under increasing pressure. However, a new series of reports by market analyst Datamonitor reveals that wind farm projects can still be profitable and competitive under very specific financial, technical, regulatory and legislative conditions [nl

  18. Optimal Control of a Wind Farm Group Using the WindEx System

    Directory of Open Access Journals (Sweden)

    Piotr Kacejko

    2014-09-01

    Full Text Available The aim of this paper is to present achievements obtained in implementing the framework project N R01 0021 06 in the Power System Department of Lublin University of Technology. The result of the work was “A system of optimal wind farm power control in the conditions of limited transmission capabilities of power networks”, which one of two main modules is a state estimator. The featured wind farm control system was integrated with a SCADA dispatcher system WindEx using the WebSVC service.

  19. Overall Optimization for Offshore Wind Farm Electrical System

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Cong

    2017-01-01

    Based on particle swarm optimization (PSO), an optimization platform for offshore wind farm electrical system (OWFES) is proposed in this paper, where the main components of an offshore wind farm and key technical constraints are considered as input parameters. The offshore wind farm electrical...... system is optimized in accordance with initial investment by considering three aspects: the number and siting of offshore substations (OS), the cable connection layout of both collection system (CS) and transmission system (TS) as well as the selection of electrical components in terms of voltage level...... that save 3.01% total cost compared with the industrial layout, and can be a useful tool for OWFES design and evaluation....

  20. Transient stability probability evaluation of power system incorporating with wind farm and SMES

    DEFF Research Database (Denmark)

    Fang, Jiakun; Miao, Lu; Wen, Jinyu

    2013-01-01

    Large scale renewable power generation brings great challenges to the power system operation and stabilization. Energy storage is one of the most important technologies to face the challenges. This paper proposes a method for transient stability probability evaluation of power system with wind farm...... and SMES. Firstly, a modified 11-bus test system with both wind farm and SMES has been implemented. The wind farm is represented as a doubly fed induction generator (DFIG). Then a stochastic-based approach to evaluate the probabilistic transient stability index of the power system is presented. Uncertain...... the probability indices. With the proposed method based on Monte-Carlo simulation and bisection method, system stability is "measured". Quantitative relationship of penetration level, SMES coil size and system stability is established. Considering the stability versus coil size to be the production curve...

  1. Application of SMES in wind farm to improve voltage stability

    International Nuclear Information System (INIS)

    Shi, J.; Tang, Y.J.; Ren, L.; Li, J.D.; Chen, S.J.

    2008-01-01

    For the wind farms introducing doubly fed induction generators (DFIGs), voltage stability is an essential issue which influences their widely integration into the power grid. This paper proposes the application of superconducting magnetic energy storage (SMES) in the power system integrated with wind farms. SMES can control the active and reactive power flow, realizing the operation in four quadrants independently. The introducing of SMES can smooth the output power flow of the wind farms, and supply dynamic voltage support. Using MATLAB/SIMULINK, the models of the DFIG, the power grid connected and the SMES are created. Simulation results show that the voltage stability of the power system integrated with wind farms can be improved considerably

  2. Regional climate model simulations indicate limited climatic impacts by operational and planned European wind farms.

    Science.gov (United States)

    Vautard, Robert; Thais, Françoise; Tobin, Isabelle; Bréon, François-Marie; Devezeaux de Lavergne, Jean-Guy; Colette, Augustin; Yiou, Pascal; Ruti, Paolo Michele

    2014-01-01

    The rapid development of wind energy has raised concerns about environmental impacts. Temperature changes are found in the vicinity of wind farms and previous simulations have suggested that large-scale wind farms could alter regional climate. However, assessments of the effects of realistic wind power development scenarios at the scale of a continent are missing. Here we simulate the impacts of current and near-future wind energy production according to European Union energy and climate policies. We use a regional climate model describing the interactions between turbines and the atmosphere, and find limited impacts. A statistically significant signal is only found in winter, with changes within ±0.3 °C and within 0-5% for precipitation. It results from the combination of local wind farm effects and changes due to a weak, but robust, anticyclonic-induced circulation over Europe. However, the impacts remain much weaker than the natural climate interannual variability and changes expected from greenhouse gas emissions.

  3. An Optimal Control Scheme to Minimize Loads in Wind Farms

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2012-01-01

    This work presents a control algorithm for wind farms that optimizes the power production of the farm and helps to increase the lifetime of wind turbines components. The control algorithm is a centralized approach, and it determines the power reference signals for individual wind turbines...

  4. Economic optimization of offshore wind farms

    International Nuclear Information System (INIS)

    Pauling, T.

    1996-09-01

    The study on the title subject continues the development of a cost model for offshore wind farms started at the Institute for Wind Energy (IW) in 1995, and applies it on different kinds of cost analyses. The model will be considered within the European research project 'Structural and Economic Optimization of Bottom-Mounted Offshore Wind Energy Converters' (Opti-OWECS, JOR3-CT95-0087) co-ordinated by the IW, where also the cost analyses and optimization will be extended. The conclusions of the investigations have already been presented at the European Union Wind Energy Conference '96 at Goeteborg, Sweden. In Chapter 1, a short overview of former offshore studies and projects is given, especially those dealing with cost analysis. Typical cost breakdowns of offshore and onshore wind farms are compared. Chapter 2 contains a brief description of the cost model in its present state. The recent improvements and extensions are documented in Chapter 3, and a validation by means of a recalculation of two former offshore studies is carried out in Chapter 4. In Chapter 5, four different offshore sites are compared with respect to the same farm size and an optimized farm design: Jade in the German part of the North Sea near Wilhelmshafen; Swansea Bay in the Bristol Channel at the British Atlantic Coast; Rostock at the German Baltic Coast, and IJmuiden in the Dutch part of the North Sea. In Chapter 6, a sensitivity study is carried out for a variety of site, design and economical parameters. The results of this project are summarized in Chapter 7, and an outlook is given in Chapter 8. The appendix contains among others a description of the SCOptiM2 code, where the model is implemented, as well as data obtained from the parameter studies and design optimizations. 30 figs., 8 tabs., 6 appendices, 40 refs

  5. Extreme wind estimate for Hornsea wind farm

    DEFF Research Database (Denmark)

    Larsén, Xiaoli Guo

    The purpose of this study is to provide estimation of the 50-year winds of 10 min and 1-s gust value at hub height of 100 m, as well as the design parameter shear exponent for the Hornsea offshore wind farm. The turbulence intensity required for estimating the gust value is estimated using two...... approaches. One is through the measurements from the wind Doppler lidar, WindCube, which implies serious uncertainty, and the other one is through similarity theory for the atmospheric surface layer where the hub height is likely to belong to during strong storms. The turbulence intensity for storm wind...... strength is taken as 0.1. The shear exponents at several heights were calculated from the measurements. The values at 100 m are less than the limit given by IEC standard for all sectors. The 50-year winds have been calculated from various global reanalysis and analysis products as well as mesoscale models...

  6. Simulation analysis of a wind farm with different aggregated models

    DEFF Research Database (Denmark)

    Li, H.; Wang, H.; Zhao, B.

    2011-01-01

    Based on a wind farm including wind turbines with squirrel cage induction generators (SCIGs), different aggregated models of a wind farm, such as a single weighted average model, a reduced-order re-scaled model, a parameter transformed model and a single weighted arithmetic model were presented, ...

  7. Combination of Deterministic and Probabilistic Meteorological Models to enhance Wind Farm Power Forecasts

    International Nuclear Information System (INIS)

    Bremen, Lueder von

    2007-01-01

    Large-scale wind farms will play an important role in the future worldwide energy supply. However, with increasing wind power penetration all stakeholders on the electricity market will ask for more skilful wind power predictions regarding save grid integration and to increase the economic value of wind power. A Neural Network is used to calculate Model Output Statistics (MOS) for each individual forecast model (ECMWF and HIRLAM) and to model the aggregated power curve of the Middelgrunden offshore wind farm. We showed that the combination of two NWP models clearly outperforms the better single model. The normalized day-ahead RMSE forecast error for Middelgrunden can be reduced by 1% compared to single ECMWF. This is a relative improvement of 6%. For lead times >24h it is worthwhile to use a more sophisticated model combination approach than simple linear weighting. The investigated principle component regression is able to extract the uncorrelated information from two NWP forecasts. The spread of Ensemble Predictions is related to the skill of wind power forecasts. Simple contingency diagrams show that low spread corresponds is more often related to low forecast errors and high spread to large forecast errors

  8. Wind Farms Community Engagement Good Practice Review

    DEFF Research Database (Denmark)

    Aitken, Mhairi; Haggett, Claire; Rudolph, David Philipp

    2014-01-01

    This report sets out the findings of a review of community engagement for wind farm developments. We focus in particular on the engagement carried out by developers with communities. The aims of the study were to evaluate current good practice for engaging people in decision making about on......- and offshore wind farms in different European countries; to evaluate the effect that different practices have on public opinion and acceptance; and to make relevant recommendations for Scottish policy and planning....

  9. Base line studies North Sea wind farms

    NARCIS (Netherlands)

    Krijgsveld, K.L.; Lieshout, S.M.J.; Schekkerman, H.; Lensink, Rick; Poot, M.J.M.; Dirksen, S.

    2003-01-01

    The Dutch government has granted ‘Noordzeewind’ (Nuon Renewable Energy Projects and Shell Wind Energy) the possibility to build a wind farm consisting of 36 wind turbines off the coast of the Netherlands, near Egmond. This project serves to evaluate the economical, technical, ecological and social

  10. Optimization of offshore wind farm layout in restricted zones

    International Nuclear Information System (INIS)

    Hou, Peng; Hu, Weihao; Chen, Cong; Soltani, Mohsen; Chen, Zhe

    2016-01-01

    In this research, an optimization method for offshore wind farm layout design is proposed. With the purpose of maximizing the energy production of the wind farm, the wind turbine (WT) positions are optimized. Due to the limitations of seabed conditions, marine traffic limitations or shipwrecks, etc., the WTs are expected to be placed outside specific areas. Based on this fact, a restriction zone concept is proposed in this paper and implemented with the penalty function method. In order to find a feasible solution, a recent proposed stochastic algorithm, particle swarm optimization algorithm with multiple adaptive methods (PSO-MAM) is adopted. The simulation results indicate that the proposed method can find a layout which outperforms a baseline layout of a reference wind farm (RWF) by increasing the energy yield by 3.84%. - Highlights: • The offshore restricted area concept is proposed. • The recent developed PSO-MAM algorithm is arranged to optimize the layout. • The penalty function method is adopted to help find the feasible solution. • The optimized layout increases energy yields 3.84% than reference wind farm.

  11. Collision risk of birds with modern large wind turbines

    NARCIS (Netherlands)

    Krijgsveld, K.L.; Akershoek, K.; Schenk, F.; Dijk, van F.; Dirksen, J.

    2009-01-01

    We studied collision rate of birds with modern, large 1.65 MW wind turbines in three wind farms in The Netherlands during three months in autumn and winter. Collision rate, after correction for retrieval and disappearance rate, was 0.08 birds per turbine per day on average (range 0.05-0.19).

  12. Monitoring and evaluation of Blyth Offshore Wind Farm. NAVAID (Navigational Aid) requirements for UK offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Pepper, L.

    2001-07-01

    The principle aim of this report is to review and evaluate the Navigational Aid (NAVAID) requirements for the Blyth Offshore Wind Farms as specified by Trinity House. The effectiveness of the NAVAIDs was monitored and reviewed by the project team with the assistance of the harbour master and the local vessel operators regularly using Blyth Harbour. This report particularly looks at the reasons for the NAVAID specification and the practicalities of using a similar system on larger offshore wind farms. The document not only describes the specification, but also reviews its effectiveness including any difficulties that were encountered during the installation. (author)

  13. The assessment and rating of noise from wind farms. Final report

    International Nuclear Information System (INIS)

    1996-09-01

    The findings of a Working Group on Wind Turbine Noise in the United Kingdom are presented. The broad topics covered are: the philosophy and practice of noise emission control; description of noise emission from wind turbines; a review of current practice and guidance; a survey of public reaction to noise from wind farms; recommendations on noise limits; noise monitoring; the planning obligation. In deriving suggested noise limits, a reasonable degree of protection to wind farm neighbours has been sought which will not place unreasonable restrictions and undue added costs and administrative burdens on wind farm developers or local authorities. Examples of practice in the control of noise emissions at wind farms in the United Kingdom and the USA are assembled in an Appendix. (29 figures; 13 tables; 32 references) (UK)

  14. Load flow analysis for variable speed offshore wind farms

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhao, Menghua; Blaabjerg, Frede

    2009-01-01

    factors such as the different wind farm configurations, the control of wind turbines and the power losses of pulse width modulation converters are considered. The DC/DC converter model is proposed and integrated into load flow algorithm by modifying the Jacobian matrix. Two iterative methods are proposed...... and integrated into the load flow algorithm: one takes into account the control strategy of converters and the other considers the power losses of converters. In addition, different types of variable speed wind turbine systems with different control methods are investigated. Finally, the method is demonstrated......A serial AC-DC integrated load flow algorithm for variable speed offshore wind farms is proposed. It divides the electrical system of a wind farm into several local networks, and different load flow methods are used for these local networks sequentially. This method is fast, more accurate, and many...

  15. New software for improving performance in wind farm operations

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Mark [Ekho for Wind (Canada)

    2011-07-01

    The performance of wind farms depends on multiple field and business systems. This makes operational planning difficult because of so many data being in separate systems, duplication of data and the impossibility of gathering all relevant data together in one place. The aim of this paper is to present a new software, Ekho for Wind, which helps improve performance in wind farm operations by providing features such as high level views, performance analysis, downtime tracking, quality data management and forecast generation. This new software provides operational intelligence which offers incentives for continuous improvement. Ekho for Wind can bring such benefits as maximization of generation, increased lifetime of assets, minimization of costs and increased profitability. This presentation introduced a new software for improving the performance of wind farms and the lifetime of assets, resulting in significant payback.

  16. A simulated-annealing-based approach for wind farm cabling

    NARCIS (Netherlands)

    Lehmann, S.; Rutter, I.; Wagner, D.; Wegner, F.

    2017-01-01

    We study the problem of computing a wind farm cabling with minimum costs allowing different cable types. Our model distinguishes different levels of granularity, where the highest level represents the cabling problem for the whole wind farm. Since even the most restricted of these problems is

  17. Benefits of Two Turbine Rotor Diameters and Hub Heights in the Same Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Stanley, Andrew P. J. [Brigham Young University; Ning, Andrew [Brigham Young University

    2018-01-12

    Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms with non-homogeneous turbines, especially when the turbines are spaced close together. For a unidirectional wind rose, including different turbine design in the wind farm has a similar decrease in COE to spreading the wind turbines farther apart. When the rotor diameter and hub height of the wind turbines in a farm are optimized uniformly, a COE decrease of 4% to 13% (depending on the grid spacing and wind shear exponent) is achieved compared to the baseline. When the rotor diameter and turbine heights are optimized non-uniformly, with two different diameters and heights throughout the farm, there is a COE decrease of 22% to 41% compared to the baseline. For a more spread wind rose with a dominant probability from the west, there is a COE decrease between 3% and 10% for uniformly optimized rotor diameter and height compared to the baseline. With two optimized rotor diameters and heights through the farm, a COE decrease of 3% to 19% is achieved. For a similar wind rose shifted such that the dominant wind direction is from the northwest, a COE decrease between 3% and 10% results from uniformly optimized wind turbines compared to the baseline. A COE decrease of 3% to 17% compared to the baseline occurs with two different turbines are optimized throughout the wind farm.

  18. Simulation of an offshore wind farm using fluid power for centralized electricity generation

    Directory of Open Access Journals (Sweden)

    A. Jarquin Laguna

    2017-07-01

    Full Text Available A centralized approach for electricity generation within a wind farm is explored through the use of fluid power technology. This concept considers a new way of generation, collection and transmission of wind energy inside a wind farm, in which electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A numerical model was developed to capture the relevant physics from the dynamic interaction between different turbines coupled to a common hydraulic network and controller. This paper presents a few examples of the time domain simulation results for a hypothetical hydraulic wind farm subject to turbulent wind conditions. The performance and operational parameters of individual turbines are compared with those of a reference wind farm based on conventional wind turbine generator technology using the same wind farm layout and environmental conditions. For the presented case studies, results indicate that the individual wind turbines are able to operate within operational limits. Despite the stochastic turbulent wind conditions and wake effects, the hydraulic wind farm is able to produce electricity with reasonable performance in both below and above rated conditions. With the current pressure control concept, a continuous operation of the hydraulic wind farm is shown including the full stop of one or more turbines.

  19. A Review of Methodological Approaches for the Design and Optimization of Wind Farms

    DEFF Research Database (Denmark)

    Herbert-Acero, José F.; Probst, Oliver; Réthoré, Pierre-Elouan

    2014-01-01

    This article presents a review of the state of the art of the Wind Farm Design and Optimization (WFDO) problem. The WFDO problem refers to a set of advanced planning actions needed to extremize the performance of wind farms, which may be composed of a few individual Wind Turbines (WTs) up to thou...... and offshore wind farms; and (3) to propose a comprehensive agenda for future research.......This article presents a review of the state of the art of the Wind Farm Design and Optimization (WFDO) problem. The WFDO problem refers to a set of advanced planning actions needed to extremize the performance of wind farms, which may be composed of a few individual Wind Turbines (WTs) up...

  20. Optimisation of Offshore Wind Farm Cable Connection Layout Considering Levelised Production Cost Using Dynamic Minimum Spanning Tree Algorithm

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Cong

    2016-01-01

    The approach in this paper hads been developed to optimize the cable connection layout of large scale offshore wind farms. The objective is to minimize the Levelised Production Cost (LPC) og an offshore wind farm by optimizing the cable connection configuration. Based on the minimum spanning tree...... (MST) algorithm, an improved algorithm, the Dynamic Minimum Spanning Tree (DMST) algorithm is proposed. The current carrying capacity of the cable is considered to be the main constraint and the cable sectional area is changed dynamically. An irregular shaped wind farm is chosen as the studie case...

  1. Wind tunnel study of the power output spectrum in a micro wind farm

    International Nuclear Information System (INIS)

    Bossuyt, Juliaan; Meyers, Johan; Howland, Michael F.; Meneveau, Charles

    2016-01-01

    Instrumented small-scale porous disk models are used to study the spectrum of a surrogate for the power output in a micro wind farm with 100 models of wind turbines. The power spectra of individual porous disk models in the first row of the wind farm show the expected -5/3 power law at higher frequencies. Downstream models measure an increased variance due to wake effects. Conversely, the power spectrum of the sum of the power over the entire wind farm shows a peak at the turbine-to-turbine travel frequency between the model turbines, and a near -5/3 power law region at a much wider range of lower frequencies, confirming previous LES results. Comparison with the spectrum that would result when assuming that the signals are uncorrelated, highlights the strong effects of correlations and anti-correlations in the fluctuations at various frequencies. (paper)

  2. Integration and control of wind farms in the Danish electricity system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bak-Jensen, B. (ed.); Suwannarat, A.; Chen, Z. (Aalborg Univ.. Dept. of Energy Technology, Aalborg (Denmark)) (and others)

    2009-07-01

    due to too high wind speed. First simulations, where only the central power plants and the decentralized combined heat and power plants participate in the balancing is performed, then the simulations are extended with the usage of the Great Belt Link and the links to Norway and Sweden, and finally also the usage of delta control in the wind farm and the ability to include planned power for the power plants is used. .From these simulations one can see the importance of using planned power, different control methods for the wind farms and being able to use the connections to our neighboring countries. It is found that this is decisive for the balancing situation in Denmark, and for the possibility to cope with large wind power penetration in the future. (LN)

  3. Landscape integration and harmonization assessment guide : wind farm siting project on public land

    Energy Technology Data Exchange (ETDEWEB)

    Bouchard, M.A.; Boudart, M.; Arsenault, M.; Lauzon, M.; Lizotte, C.; Munoz, P.; Poirier, C.; Guimont, C.; Sainte-Marie, L.

    2005-07-01

    The development of a wind farm industry depends greatly on obtaining land use rights. This paper describes a program created by the Quebec Government to make public land available for wind farm construction. In particular, the program allows the government to set aside public land to promote the development of the wind industry in the Gaspe Region and the Matane Regional County Municipality. It also awards land rights for wind farm construction to bidders who have signed wind energy sales contracts with Hydro-Quebec Distribution. The program allows the government to set lease rates for public land used for wind farms based on market rates. This document is a guide used by Quebec's Ministry of Natural Resources to evaluate projects and issue leases for parcels of public land to be used for wind turbine arrays. It identifies major landscape issues associated with wind farms and allows proponents to demonstrate the natural and anthropogenic impacts of a wind farm on the landscape and present mitigative measures to minimize these impacts. This document also identifies the wind farm landscape integration and harmonization principles for public lands in Quebec. It was noted that wind farm projects with 10 MW capacity or less are not subject to guidelines established by the Quebec Ministry of Sustainable Development, Environment and Parks. 23 refs., 2 tabs.

  4. Smoothing Control of Wind Farm Output by Using Kinetic Energy of Variable Speed Wind Power Generators

    Science.gov (United States)

    Sato, Daiki; Saitoh, Hiroumi

    This paper proposes a new control method for reducing fluctuation of power system frequency through smoothing active power output of wind farm. The proposal is based on the modulation of rotaional kinetic energy of variable speed wind power generators through power converters between permanent magnet synchronous generators (PMSG) and transmission lines. In this paper, the proposed control is called Fluctuation Absorption by Flywheel Characteristics control (FAFC). The FAFC can be easily implemented by adding wind farm output signal to Maximum Power Point Tracking control signal through a feedback control loop. In order to verify the effectiveness of the FAFC control, a simulation study was carried out. In the study, it was assumed that the wind farm consisting of PMSG type wind power generator and induction machine type wind power generaotors is connected with a power sysem. The results of the study show that the FAFC control is a useful method for reducing the impacts of wind farm output fluctuation on system frequency without additional devices such as secondary battery.

  5. Responses of two marine top predators to an offshore wind farm.

    Science.gov (United States)

    Vallejo, Gillian C; Grellier, Kate; Nelson, Emily J; McGregor, Ross M; Canning, Sarah J; Caryl, Fiona M; McLean, Nancy

    2017-11-01

    Quantifying the likely effects of offshore wind farms on wildlife is fundamental before permission for development can be granted by any Determining Authority. The effects on marine top predators from displacement from important habitat are key concerns during offshore wind farm construction and operation. In this respect, we present evidence for no significant displacement from a UK offshore wind farm for two broadly distributed species of conservation concern: common guillemot ( Uria aalge ) and harbor porpoise ( Phocoena phocoena ). Data were collected during boat-based line transect surveys across a 360 km 2 study area that included the Robin Rigg offshore wind farm. Surveys were conducted over 10 years across the preconstruction, construction, and operational phases of the development. Changes in guillemot and harbor porpoise abundance and distribution in response to offshore wind farm construction and operation were estimated using generalized mixed models to test for evidence of displacement. Both common guillemot and harbor porpoise were present across the Robin Rigg study area throughout all three development phases. There was a significant reduction in relative harbor porpoise abundance both within and surrounding the Robin Rigg offshore wind farm during construction, but no significant difference was detected between the preconstruction and operational phases. Relative common guillemot abundance remained similar within the Robin Rigg offshore wind farm across all development phases. Offshore wind farms have the potential to negatively affect wildlife, but further evidence regarding the magnitude of effect is needed. The empirical data presented here for two marine top predators provide a valuable addition to the evidence base, allowing future decision making to be improved by reducing the uncertainty of displacement effects and increasing the accuracy of impact assessments.

  6. Modelling seabird collision risk with off-shore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Mateos, Maria; Arroyo, Gonzalo Munoz; Rosario, Jose Juan Alonso del

    2011-07-01

    Full text: Recent concern about the adverse effects of collision mortality of avian migrants at wind farms has highlighted the need to understand bird-wind turbine interactions. Here, a stochastic collision model, based on data of seabird behaviour collected on- site, is presented, as a flexible and easy to take tool to assess the collisions probabilities of off-shore wind farms in a pre-construction phase. The collision prediction model considering the wind farm area as a risk window has been constructed as a stochastic model for avian migrants, based on Monte Carlo simulation. The model calculates the probable number of birds collided per time unit. Migration volume, wind farm dimensions, vertical and horizontal distribution of the migratory passage, flight direction and avoidance rates, between other variables, are taken into account in different steps of the model as the input variables. In order to assess the weighted importance of these factors on collision probability predictions, collision probabilities obtained from the set of scenarios resulting from the different combinations of the input variables were modelled by using Generalised Additive Models. The application of this model to a hypothetical project for erecting a wind farm at the Strait of Gibraltar showed that collision probability, and consequently mortality rates, strongly depend on the values of the avoidance rates taken into account, and the distribution of birds into the different altitude layers. These parameters should be considered as priorities to be addressed in post-construction studies. (Author)

  7. Optimisation of electrical system for offshore wind farms via genetic algorithm

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhao, Menghua; Blaabjerg, Frede

    2009-01-01

    An optimisation platform based on genetic algorithm (GA) is presented, where the main components of a wind farm and key technical specifications are used as input parameters and the electrical system design of the wind farm is optimised in terms of both production cost and system reliability....... The power losses, wind power production, initial investment and maintenance costs are considered in the production cost. The availability of components and network redundancy are included in the reliability evaluation. The method of coding an electrical system to a binary string, which is processed by GA......, is developed. Different GA techniques are investigated based on a real example offshore wind farm. This optimisation platform has been demonstrated as a powerful tool for offshore wind farm design and evaluation....

  8. The structure and strength of public attitudes towards wind farm development

    Science.gov (United States)

    Bidwell, David Charles

    A growing social science literature seeks to understand why, despite broad public support for wind energy, proposals for specific projects are often met with strong local opposition. This gap between general and specific attitudes is viewed as a significant obstacle to the deployment of wind energy technologies. This dissertation applies theoretical perspectives and methodological tools from social psychology to provide insights on the structure and strength of attitudes towards the potential development of commercial wind farm in three coastal areas of Michigan. A survey of attitudes was completed by 375 residents in these communities and structural equation modeling was used to explore the relationship among variables. The analysis found that attitudes towards wind farm development are shaped by anticipated economic benefits to the community, but expectations of economic benefit are driven by personal values. Social psychology has long recognized that all attitudes are not created equal. Weak attitudes are fleeting and prone to change, while strong attitudes are stable over time and resistant to change. There are two fundamental paths to strong attitudes: repeated experience with an attitude object or the application of deeply held principles or values to that object. Structural equation models were also used to understand the strength of attitudes among the survey respondents. Both the anticipated effects of wind farm development and personal values were found to influence the strength of attitudes towards wind farms. However, while expectations that wind farm development will have positive effects on the economy bolster two measures of attitude strength (collective identity and importance), these expectations are associated with a decline in a third measure (confidence). A follow-up survey asking identical questions was completed by completed by 187 respondents to the initial survey. Linear regressions models were used to determine the effects of attitude

  9. Maximum generation power evaluation of variable frequency offshore wind farms when connected to a single power converter

    Energy Technology Data Exchange (ETDEWEB)

    Gomis-Bellmunt, Oriol; Sumper, Andreas [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2, 08028 Barcelona (Spain); IREC Catalonia Institute for Energy Research, Barcelona (Spain); Junyent-Ferre, Adria; Galceran-Arellano, Samuel [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2, 08028 Barcelona (Spain)

    2010-10-15

    The paper deals with the evaluation of power generated by variable and constant frequency offshore wind farms connected to a single large power converter. A methodology to analyze different wind speed scenarios and system electrical frequencies is presented and applied to a case study, where it is shown that the variable frequency wind farm concept (VF) with a single power converter obtains 92% of the total available power, obtained with individual power converters in each wind turbine (PC). The PC scheme needs multiple power converters implying drawbacks in terms of cost, maintenance and reliability. The VF scheme is also compared to a constant frequency scheme CF, and it is shown that a significant power increase of more than 20% can be obtained with VF. The case study considers a wind farm composed of four wind turbines based on synchronous generators. (author)

  10. Robust lidar-based closed-loop wake redirection for wind farm control

    NARCIS (Netherlands)

    Raach, Steffen; Boersma, S.; van Wingerden, J.W.; Schlipf, David; Cheng, Po Wen; Dochain, Denis; Henrion, Didier; Peaucelle, Dimitri

    2017-01-01

    Wind turbine wake redirection is a promising concept for wind farm control to increase the total power of a wind farm. Further, the concept aims to avoid partial wake overlap on a downwind wind turbine and hence aims to decrease structural loads. Controller for wake redirection need to account

  11. A Wind Farm Active Power Dispatch Strategy for Fatigue Load Reduction

    DEFF Research Database (Denmark)

    Zhang, Baohua; N. Soltani, Mohsen; Hu, Weihao

    2016-01-01

    One of the biggest challenges in wind farm management is to cope with requirements from the grid companies and to optimize efficiency and minimize wear on wind turbines. This paper addresses an optimized active power dispatch strategy of a wind farm to reduce the fatigue load of wind turbines, wh...

  12. Development of an advanced noise propagation model for noise optimization in wind farm

    DEFF Research Database (Denmark)

    Barlas, Emre

    2017-01-01

    Increasing demand in renewable energy has resulted in large wind energy deployment. Even though wind turbines are among the most environmentally friendly way of generating electricity, the noise emitted by them is one of the main obstacles for further installation. Wind farm developers rely...... wind directions or time of the day). The latter causes turbines to be located at less resourceful sites in advance. Both of these scenarios increase the cost of energy. Hence there is a need for more accurate noise mapping tools. The thesis addresses this issue via development of a new tool based...... field sound pressure levels are addressed both in steady and unsteady manner. Enhanced far fields amplitude modulation is observed and associated with the wake dynamics and the rotating blades. Lastly, the developed tool is used for an onshore wind farm noise prediction taking the terrain and the flow...

  13. Wind farm power production in the changing wind: Robustness quantification and layout optimization

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2017-01-01

    Wind farms operate often in the changing wind. The wind condition variations in a wide range of time scales lead to the variability of wind farms’ power production. This imposes a major challenge to the power system operators who are facing a higher and higher penetration level of wind power. Thu...

  14. 76 FR 35882 - Paulding Wind Farm II, LLC, et al.;

    Science.gov (United States)

    2011-06-20

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket Nos. EG11-61-000, etc.] Paulding Wind Farm II, LLC, et al.; Notice of Effectiveness of Exempt Wholesale Generator Status Docket Nos. Paulding Wind Farm II LLC EG11-61-000 Macho Springs Power I, LLC EG11-63-000 Alta Wind III Owner Lessor A...

  15. Assessing noise from wind farm developments in Ireland: A consideration of critical wind speeds and turbine choice

    International Nuclear Information System (INIS)

    King, E.A.; Pilla, F.; Mahon, J.

    2012-01-01

    Wind farms are becoming increasingly popular in Ireland in an effort to increase the production of green energy within the state. As with any infrastructural development, wind farms must consider potential environmental impacts prior to construction. One particular issue that must be examined is the emission of noise from the development. In Ireland wind farm developments must adhere to planning conditions that usually outline permissible noise levels for both the construction and operational phases of the development. The critical wind speed is often cited as the wind speed at which these limits apply. This paper examines how the critical wind speed is determined and investigates its relationship with background noise levels and turbine choice. The study consisted of ten one-week monitoring periods during which meteorological conditions and background noise levels were simultaneously recorded. It was found that the critical wind speed is non-transferable, i.e. it depends on both the turbine choice and background noise environment and is specific to that particular turbine/site combination. Furthermore the critical wind speed during the night-time is often different to the overall critical wind speed suggesting that future noise studies should consider a range of critical wind speeds, particularly for night-time noise assessments. - Highlights: ► This paper considers the use of the critical wind speed when assessing noise impacts from wind farms. ► It was found that the critical wind speed could vary depending on the time of the day. ► The critical wind speed was found to be a non-transferable value. ► Noise assessments for wind farms should be developed over a range of critical wind speeds.

  16. The Pattern of Complaints about Australian Wind Farms Does Not Match the Establishment and Distribution of Turbines: Support for the Psychogenic, ‘Communicated Disease’ Hypothesis

    Science.gov (United States)

    Chapman, Simon; St. George, Alexis; Waller, Karen; Cakic, Vince

    2013-01-01

    Background and Objectives With often florid allegations about health problems arising from wind turbine exposure now widespread, nocebo effects potentially confound any future investigation of turbine health impact. Historical audits of health complaints are therefore important. We test 4 hypotheses relevant to psychogenic explanations of the variable timing and distribution of health and noise complaints about wind farms in Australia. Setting All Australian wind farms (51 with 1634 turbines) operating 1993–2012. Methods Records of complaints about noise or health from residents living near 51 Australian wind farms were obtained from all wind farm companies, and corroborated with complaints in submissions to 3 government public enquiries and news media records and court affidavits. These are expressed as proportions of estimated populations residing within 5 km of wind farms. Results There are large historical and geographical variations in wind farm complaints. 33/51 (64.7%) of Australian wind farms including 18/34 (52.9%) with turbine size >1 MW have never been subject to noise or health complaints. These 33 farms have an estimated 21,633 residents within 5 km and have operated complaint-free for a cumulative 267 years. Western Australia and Tasmania have seen no complaints. 129 individuals across Australia (1 in 254 residents) appear to have ever complained, with 94 (73%) being residents near 6 wind farms targeted by anti wind farm groups. The large majority 116/129(90%) of complainants made their first complaint after 2009 when anti wind farm groups began to add health concerns to their wider opposition. In the preceding years, health or noise complaints were rare despite large and small-turbine wind farms having operated for many years. Conclusions The reported historical and geographical variations in complaints are consistent with psychogenic hypotheses that expressed health problems are “communicated diseases” with nocebo effects likely to play an

  17. Benchmarking of wind farm scale wake models in the EERA - DTOC project

    DEFF Research Database (Denmark)

    Réthoré, Pierre-Elouan; Hansen, Kurt Schaldemose; Barthelmie, R.J.

    2013-01-01

    -flow to combine wind farm (micro) and cluster (meso) scale wake models. For this purpose, a benchmark campaign is organized on the existing wind farm wake models available within the project, in order to identify which model would be the most appropriate for this coupling. A number of standardized wake cases......Designing offshore wind farms next to existing or planned wind farm clusters has recently become a common practice in the North Sea. These types of projects face unprecedented challenges in term of wind energy siting. The currently ongoing European project FP7 EERA - DTOC (Design Tool for Offshore...... wind farm Clusters) is aiming at providing a new type of model work-flow to address this issue. The wake modeling part of the EERA - DTOC project is to improve the fundamental understanding of wind turbine wakes and modeling. One of these challenges is to create a new kind of wake modeling work...

  18. Bats in Dutch offshore wind farms in autumn 2012

    NARCIS (Netherlands)

    Lagerveld, S.; Jonge Poerink, B.; Haselager, R.; Verdaat, J.P.

    2014-01-01

    In the autumn of 2012, we conducted a pilot study with ultrasonic recorders to assess the occurrence of bats over the North Sea. At Offshore Wind Farm Egmond aan Zee (OWEZ) a recorder was installed at the meteorological mast and at Princess Amalia Wind Farm (PAWP) a recorder was attached to the

  19. Energy costs form European wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Milborrow, D [Windpower Monthly, Knebel (Denmark)

    1996-12-31

    Energy generation costs from European wind farms span a very wide range. Reasons for these variations, include differences in capital and operating costs, wind speeds and differing legislative and regulatory frameworks. This article compares costs, wind speeds and discount rates for British and German windfarms and sets these alongside data from elsewhere in the European Union. In this way it is possible to determine the reasons for differences in energy generation costs. (author)

  20. Energy costs form European wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Milborrow, D. [Windpower Monthly, Knebel (Denmark)

    1995-12-31

    Energy generation costs from European wind farms span a very wide range. Reasons for these variations, include differences in capital and operating costs, wind speeds and differing legislative and regulatory frameworks. This article compares costs, wind speeds and discount rates for British and German windfarms and sets these alongside data from elsewhere in the European Union. In this way it is possible to determine the reasons for differences in energy generation costs. (author)

  1. Energy costs form European wind farms

    International Nuclear Information System (INIS)

    Milborrow, D.

    1995-01-01

    Energy generation costs from European wind farms span a very wide range. Reasons for these variations, include differences in capital and operating costs, wind speeds and differing legislative and regulatory frameworks. This article compares costs, wind speeds and discount rates for British and German windfarms and sets these alongside data from elsewhere in the European Union. In this way it is possible to determine the reasons for differences in energy generation costs. (author)

  2. Acoustic and geophysical measurement of infrasound from turbines at wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Hepburn, H.G. [Hepburn Exploration Inc., Canmore, AB (Canada)

    2005-07-01

    An experiment was conducted at the Castle River Wind Farm in southern Alberta to measure and characterize infrasound from the turbines. The wind farm contains one 600 MW turbine and fifty-nine 660 MW wind turbines. Three types of sensors were used to measure both the low and high frequency acoustic energy and geophysical sound levels. These included low frequency geophones, acoustic microphones and a precision sound analyzer. Data was recorded for low, medium and high wind states, with the entire wind turbine array operating, and with the entire wind farm stopped. Downwind telemetry measurements were recorded for 30 continuous 50 metre offsets, up to a distance of 1450 metres from the wind farm. The objective of the project was to characterize the ambient noise levels and sound emitted by the turbines. Measurements were taken for wind speed and direction, atmospheric pressure, atmospheric temperature and turbine related data. Visual observations included atmospheric conditions, extraneous sources of noise such as aircraft, trains, motor vehicle traffic, highway noise, bird song, crickets and the rotational state of the turbines. It was concluded that for studying low frequency sound, the linear dB scale should be used instead of the dBA scale. Measurements of frequencies down to 6.3 Hz, showed that infrasound emission from the Castle River Wind Farm is not a significant concern. Lower frequencies down to about 2.5 Hz also confirmed that infrasound emissions are not significantly above the ambient noise levels. Any infrasound emissions were strongly coupled to the ground and were attenuated quickly. Time domain measurements showed that at all wind speeds and for frequencies up to 270 Hz, wind noise was actually attenuated when the wind farm is in operation. The noise levels were higher when the turbines were not turning. This finding was confirmed through spectral analysis. 12 refs., 2 tabs., 46 figs.

  3. Life cycle assessment of a wind farm and related externalities

    DEFF Research Database (Denmark)

    Schleisner, Liselotte

    2000-01-01

    This paper concentrates on the assessment of energy and emissions related to the production and manufacture of materials for an offshore wind farm as well as a wind farm on land based on a life cycle analysis (LCA) model. In Denmark a model has been developed for life cycle assessments of different...... materials. The model is able to assess the energy use related to the production, transportation and manufacture of 1 kg of material. The energy use is divided into fuels used in order to estimate the emissions through the life cycle. In the paper the model and the attached assumptions are described......, and the model is demonstrated for two wind farms. The externalities for the wind farms are reported, showing the importance of life cycle assessment for renewable energy technologies. (C) 2000 Elsevier Science Ltd. All rights reserved....

  4. Monitoring and evaluation of Blyth Offshore Wind Farm. Projected operation and maintenance costs of UK offshore wind farms based on the experience at Blyth

    Energy Technology Data Exchange (ETDEWEB)

    Greig, E.

    2004-07-01

    This is the fifth of seven reports in this series on specific aspects of the monitoring and evaluation of the Blyth offshore wind farm project. The report assesses the operation and maintenance (O and M) costs for the wind farm in its first full year of operation, and extrapolates these costs to give indicative costs for larger projects. It identifies both planned regular costs and unplanned site maintenance costs; some costs can be attributed to 'troubleshooting' during installation and would not be expected in future years. The Blyth wind farm, the first in the UK, consists of two 2 MW wind turbines installed approximately 1 km from the coast in water about 6 m deep at low tide. The site is exposed to the full impact of the North Sea weather, breaking waves and a significant tidal range (about 5 m). Location, boat availability, weather and insurance are identified as the key factors affecting O and M costs for future offshore wind farms in the UK.

  5. Measuring power output intermittency and unsteady loading in a micro wind farm model

    OpenAIRE

    Bossuyt, Juliaan; Howland, Michael; Meneveau, Charles; Meyers, Johan

    2016-01-01

    In this study porous disc models are used as a turbine model for a wind-tunnel wind farm experiment, allowing the measurement of the power output, thrust force and spatially averaged incoming velocity for every turbine. The model's capabilities for studying the unsteady turbine loading, wind farm power output intermittency and spatio temporal correlations between wind turbines are demonstrated on an aligned wind farm, consisting of 100 wind turbine models.

  6. A fast wind-farm boundary-layer model to investigate gravity wave effects and upstream flow deceleration

    Science.gov (United States)

    Allaerts, Dries; Meyers, Johan

    2017-11-01

    Wind farm design and control often relies on fast analytical wake models to predict turbine wake interactions and associated power losses. Essential input to these models are the inflow velocity and turbulent intensity at hub height, which come from prior measurement campaigns or wind-atlas data. Recent LES studies showed that in some situations large wind farms excite atmospheric gravity waves, which in turn affect the upstream wind conditions. In the current study, we develop a fast boundary-layer model that computes the excitation of gravity waves and the perturbation of the boundary-layer flow in response to an applied force. The core of the model is constituted by height-averaged, linearised Navier-Stokes equations for the inner and outer layer, and the effect of atmospheric gravity waves (excited by the boundary-layer displacement) is included via the pressure gradient. Coupling with analytical wake models allows us to study wind-farm wakes and upstream flow deceleration in various atmospheric conditions. Comparison with wind-farm LES results shows excellent agreement in terms of pressure and boundary-layer displacement levels. The authors acknowledge support from the European Research Council (FP7-Ideas, Grant No. 306471).

  7. Sociological investigation of the reception of Nysted Offshore wind farm. Annual report 2004[Denmark

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-08-15

    This annual report presents the work related to the sociological part of a socio-economic project that examines the effects on the local communities of the two demonstration off-shore wind farms: Horns Rev Offshore Wind Farm, west of Blaavands Huk in Jutland, and Nysted Offshore Wind Farm, south of Lolland. The socio-economic project is part of the monitoring programme in connection with the construction of the offshore wind farms. Unlike projects, which examine the impact of the wind farms on nature, the socio-economic project did not start until 2003. The other part of the socio-economic project is an environmental-economic study that among other things examines the preferences of the population in relation to location of the wind farm and the willingness to pay for increasing the distance between the wind farms and the coast. This sociological study is qualitative. The study is divided into three phases, as the aim is to investigate the public community's attitude towards the erection of an offshore wind farm before and after the construction of the wind farm. This aim is based on the assumption that attitudes may change once the wind farm is erected and the population has experienced the visibility of the wind farm, etc. The division into phases is as follows: 1) Phase 1 treats the conditions as they were before the erection of Nysted Offshore Wind Farm. 2) Phase 2 is a study of the development in attitudes towards Horns Rev Offshore Wind Farm a year after erection. 3) Phase 3 comprises a follow-up study of the local area at Nysted Offshore Wind Farm. The Horns Rev study was conclusive and was carried out September-November 2003. The study at Nysted on the other hand implies two parts. The first was carried out April-August 2003 and identified attitudes before the wind farm was completed. A follow-up study in August-December 2004 served the purpose of revealing the extent of attitude changes regarding the wind farm and the development of these changes of

  8. Measurements in support of wind farm simulations and power forecasts: The Crop/Wind-energy Experiments (CWEX)

    International Nuclear Information System (INIS)

    Takle, E S; Rajewski, D A; Lundquist, J K; Gallus, W A Jr; Sharma, A

    2014-01-01

    The Midwest US currently is experiencing a large build-out of wind turbines in areas where the nocturnal low-level jet (NLLJ) is a prominent and frequently occurring feature. We describe shear characteristics of the NLLJ and their influence on wind power production. Reports of individual turbine power production and concurrent measurements of near-surface thermal stratification are used to turbine wake interactions and turbine interaction with the overlying atmosphere. Progress in forecasting conditions such as wind ramps and shear are discussed. Finally, the pressure perturbation introduced by a line of turbines produces surface flow convergence that may create a vertical velocity and hence a mesoscale influence on cloud formation by a wind farm

  9. Wind farms providing secondary frequency regulation: evaluating the performance of model-based receding horizon control

    Directory of Open Access Journals (Sweden)

    C. R. Shapiro

    2018-01-01

    Full Text Available This paper is an extended version of our paper presented at the 2016 TORQUE conference (Shapiro et al., 2016. We investigate the use of wind farms to provide secondary frequency regulation for a power grid using a model-based receding horizon control framework. In order to enable real-time implementation, the control actions are computed based on a time-varying one-dimensional wake model. This model describes wake advection and wake interactions, both of which play an important role in wind farm power production. In order to test the control strategy, it is implemented in a large-eddy simulation (LES model of an 84-turbine wind farm using the actuator disk turbine representation. Rotor-averaged velocity measurements at each turbine are used to provide feedback for error correction. The importance of including the dynamics of wake advection in the underlying wake model is tested by comparing the performance of this dynamic-model control approach to a comparable static-model control approach that relies on a modified Jensen model. We compare the performance of both control approaches using two types of regulation signals, RegA and RegD, which are used by PJM, an independent system operator in the eastern United States. The poor performance of the static-model control relative to the dynamic-model control demonstrates that modeling the dynamics of wake advection is key to providing the proposed type of model-based coordinated control of large wind farms. We further explore the performance of the dynamic-model control via composite performance scores used by PJM to qualify plants for regulation services or markets. Our results demonstrate that the dynamic-model-controlled wind farm consistently performs well, passing the qualification threshold for all fast-acting RegD signals. For the RegA signal, which changes over slower timescales, the dynamic-model control leads to average performance that surpasses the qualification threshold, but further

  10. Compatibility Between Electric Components in Wind Farms

    DEFF Research Database (Denmark)

    Holdyk, Andrzej; Holbøll, Joachim; Arana Aristi, Iván

    2011-01-01

    The paper describes a method for investigation of the compatibility between electric components in wind farms by identifying critical resonances at different points of an offshore wind farm (OWF), based on systematic variation of critical parameters. In this way, the design of future OWF can...... be improved at a very early stage of the process. It is also revealed what parameters are the most important ones when considering compatibility. It was observed that a change of capacitance in the collection grid shifts the resonance peaks. A change in WT transformer capacitances influences the admittance...

  11. Methods development for cost-effective marine environmental monitoring at offshore wind farms in Norwegian waters

    Energy Technology Data Exchange (ETDEWEB)

    Dahlgren, Thomas; Schlaeppy, Marie-Lise; Olenin, Sergej; Shashkov, Alexej; Heggoey, Erling; Troedsson, Christofer

    2011-07-01

    Full text: Current understanding of the environmental impact from offshore wind farms and experiences in monitoring practices, are restricted to soft-bottom habitats. Due to the large expansion of this source of energy, and the national and international drive to place large parks offshore, there is at present a strong need to further increase our knowledge of the impact on the marine environment in a wider range of habitats. At a national level, it is of importance to develop monitoring methods that are suitable for Norwegian sites and that are adjusted to impact levels expected from wind parks. Biological data on the impact of offshore wind farms in marine ecosystems are predominantly focused on the southern Baltic and southern North Sea. It is shown that large wind farms do have an impact on the marine ecosystem. The most studied effects relate to the introduction of hard substrate (the turbine foundation and scour protection) in an area made exclusively of soft sediments. This leads to an introduction of a new category of fauna, a higher productivity and a shift in community structure and species composition. In addition, the construction of an offshore wind farm excludes other activities with potentially high negative impacts on the marine ecosystem such as bottom trawling. These findings are not necessary applicable to rocky shorelines such as those bordering the Norwegian coast and the first full-scale offshore wind farm, Havsul 1. The Havsul site borders an open ocean with high average yearly wind-speeds of more than 20 knots. A relatively narrow shelf and steep underwater topography creates waves of substantial heights and a benthic marine ecosystem that is fundamentally different from the shallow water, soft sediment substrates in the southern Baltic and North Seas. Instead, areas in Norway with water depths suitable for today.s design of offshore wind farms (down to a depth of about 30-50 m) have a complex topography and a mosaic of substrate types are

  12. WT Bird. Bird collision recording for offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Wiggelinkhuizen, E.J.; Rademakers, L.W.M.M.; Barhorst, S.A.M. [ECN Wind Energy, Petten (Netherlands); Den Boon, H. [E-Connection Project, Bunnik (Netherlands); Dirksen, S. [Bureau Waardenburg, Culemborg (Netherlands); Schekkerman, H. [Alterra, Wageningen (Netherlands)

    2004-11-01

    A new method for monitoring of bird collisions has been developed using video and audio registrations that are triggered by sound and vibration measurements. Remote access to the recorded images and sounds makes it possible to count the number of collisions as well as to identify the species. After the successful proof of principle and evaluation on small land-based turbines the system is now being designed for offshore wind farms. Currently the triggering system and video and audio registration are being tested on large land-based wind turbines using bird dummies. Tests of three complete prototype systems are planned for 2005.

  13. Influence of offshore wind farms layout on electrical resonances

    DEFF Research Database (Denmark)

    Holdyk, Andrzej; Holbøll, Joachim; Koldby, Erik

    2014-01-01

    , winding resistances and winding capacitances. Considering the frequency range of the present investigations, up to about 1 MHz, a lumped representation of the transformer characteristics was deemed sufficient. Breakers and capacitors are modelled as ideal components. The chosen wind farm layout includes...... ranges. The results show the influence of specific parameters being varied depending on the farm layout. In particular, cable lengths and transformer broad band characteristics turned out to have significant impact on the results....

  14. TOPFARM - next generation design tool for optimisation of wind farm topology and operation

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Aagaard Madsen, Helge; Troldborg, Niels

    for wind turbines interacting through wakes, various cost models, the optimization strategy and a priori defined constraints imposed on the wind farm topology. In TOPFARM, the object function used in the optimization platform is formulated in economical terms, thus ensuring the optimal balance between...... as of power production as seen in an economical perspective. Crucial factors in this regard are the overall wind climate at the wind farm site, the position of the individual wind turbines, the wind turbine characteristics, the internal wind farm wind climate, the wind turbine control/operation strategy...

  15. Final Report DE-EE0005380: Assessment of Offshore Wind Farm Effects on Sea Surface, Subsurface and Airborne Electronic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Hao [The University of Texas at Austin; Hamilton, Mark F. [The University of Texas at Austin Applied Research Laboratories; Bhalla, Rajan [Science Applications International Corporation; Brown, Walter E. [The University of Texas at Austin Applied Research Laboratories; Hay, Todd A. [The University of Texas at Austin Applied Research Laboratories; Whitelonis, Nicholas J. [The University of Texas at Austin; Yang, Shang-Te [The University of Texas at Austin; Naqvi, Aale R. [The University of Texas at Austin

    2013-09-30

    Offshore wind energy is a valuable resource that can provide a significant boost to the US renewable energy portfolio. A current constraint to the development of offshore wind farms is the potential for interference to be caused by large wind farms on existing electronic and acoustical equipment such as radar and sonar systems for surveillance, navigation and communications. The US Department of Energy funded this study as an objective assessment of possible interference to various types of equipment operating in the marine environment where offshore wind farms could be installed. The objective of this project was to conduct a baseline evaluation of electromagnetic and acoustical challenges to sea surface, subsurface and airborne electronic systems presented by offshore wind farms. To accomplish this goal, the following tasks were carried out: (1) survey electronic systems that can potentially be impacted by large offshore wind farms, and identify impact assessment studies and research and development activities both within and outside the US, (2) engage key stakeholders to identify their possible concerns and operating requirements, (3) conduct first-principle modeling on the interactions of electromagnetic signals with, and the radiation of underwater acoustic signals from, offshore wind farms to evaluate the effect of such interactions on electronic systems, and (4) provide impact assessments, recommend mitigation methods, prioritize future research directions, and disseminate project findings. This report provides a detailed description of the methodologies used to carry out the study, key findings of the study, and a list of recommendations derived based the findings.

  16. Simulation of an offshore wind farm using fluid power for centralized electricity generation

    International Nuclear Information System (INIS)

    Jarquin-Laguna, A

    2016-01-01

    A centralized approach for electricity generation within a wind farm is explored through the use of fluid power technology. This concept considers a new way of generation, collection and transmission of wind energy inside a wind farm, in which electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A numerical model was developed to capture the relevant physics from the dynamic interaction between different turbines coupled to a common hydraulic network and controller. This paper presents two examples of the time-domain simulation results for an hypothetical hydraulic wind farm subject to turbulent wind conditions. The performance and operational parameters of individual turbines are compared with those of a reference wind farm with conventional technology turbines, using the same wind farm layout and environmental conditions. For the presented case study, results indicate that the individual wind turbines are able to operate within operational limits with the current pressure control concept. Despite the stochastic turbulent wind input and wake effects, the hydraulic wind farm is able to produce electricity with reasonable performance in both below and above rated conditions. (paper)

  17. Stackelberg Game Model of Wind Farm and Electric Vehicle Battery Switch Station

    Science.gov (United States)

    Jiang, Zhe; Li, Zhimin; Li, Wenbo; Wang, Mingqiang; Wang, Mengxia

    2017-05-01

    In this paper, a cooperation method between wind farm and Electric vehicle battery switch station (EVBSS) was proposed. In the pursuit of maximizing their own benefits, the cooperation between wind farm and EVBSS was formulated as a Stackelberg game model by treating them as decision makers in different status. As the leader, wind farm will determine the charging/discharging price to induce the charging and discharging behavior of EVBSS reasonably. Through peak load shifting, wind farm could increase its profits by selling more wind power to the power grid during time interval with a higher purchase price. As the follower, EVBSS will charge or discharge according to the price determined by wind farm. Through optimizing the charging /discharging strategy, EVBSS will try to charge with a lower price and discharge with a higher price in order to increase its profits. Since the possible charging /discharging strategy of EVBSS is known, the wind farm will take the strategy into consideration while deciding the charging /discharging price, and will adjust the price accordingly to increase its profits. The case study proved that the proposed cooperation method and model were feasible and effective.

  18. Wind Farm parametrization in the mesoscale model WRF

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    2012-01-01

    , but are parametrized as another sub-grid scale process. In order to appropriately capture the wind farm wake recovery and its direction, two properties are important, among others, the total energy extracted by the wind farm and its velocity deficit distribution. In the considered parametrization the individual...... the extracted force is proportional to the turbine area interfacing a grid cell. The sub-grid scale wake expansion is achieved by adding turbulence kinetic energy (proportional to the extracted power) to the flow. The validity of both wind farm parametrizations has been verified against observational data. We...... turbines produce a thrust dependent on the background velocity. For the sub-grid scale velocity deficit, the entrainment from the free atmospheric flow into the wake region, which is responsible for the expansion, is taken into account. Furthermore, since the model horizontal distance is several times...

  19. Offshore wind farms in the local community - a survey at Nysted offshore wind farm. Background report; Havvindmoeller i lokalomraedet - en undersoegelse ved Nysted havmoellepark. Baggrundsrapport

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, S.

    2005-07-15

    This report is part of a socio-economic project about offshore wind farms' influence on the local community. The project is part of the monitoring programme in connection with the establishment of the offshore wind farms at Horns Rev and Nysted. The socio-economic project consists of a sociological and an environment-economic project. This report is part of the sociological project which has the purpose of identifying attitudes towards the wind farm before and after the erection with a view to identify possible changes in opinions and reasons for these changes. (BA)

  20. The collection of the main issues for wind farm optimisation in complex terrain

    DEFF Research Database (Denmark)

    Xu, Chang; Chen, Dandan; Han, Xingxing

    2016-01-01

    The paper aims at establishing the collection of the main issues for wind farm optimisation in complex terrain. To make wind farm cost effective, this paper briefly analyses the main factors influencing wind farm design in complex terrain and sets up a series of mathematical model that includes...... micro-siting, collector circuits, access roads design for optimization problems. The paper relies on the existing one year wind data in the wind farm area and uses genetic algorithm to optimize the micro-siting problem. After optimization of the turbine layout, single-source shortest path algorithm...

  1. Wind Farm Power Forecasting for Less Than an Hour Using Multi Dimensional Models

    DEFF Research Database (Denmark)

    Knudsen, Torben; Bak, Thomas; Jensen, Tom Nørgaard

    2018-01-01

    The paper focus on prediction of wind farm power for horizons of 0-10 minutes and not more than one hour using statistical methods. These short term predictions are relevant for both transmission system operators, wind farm operators and traders. Previous research indicates that for short time ho...... the prediction error variance estimate compared to the persistence method. We also present convincing examples showing that the predictions follow the wind farm power over a window of an hour.......The paper focus on prediction of wind farm power for horizons of 0-10 minutes and not more than one hour using statistical methods. These short term predictions are relevant for both transmission system operators, wind farm operators and traders. Previous research indicates that for short time...... horizons the persistence method performs as well as more complex methods. However, these results are based on accumulated power for an entire wind farm. The contribution in this paper is to develop multi-dimensional linear methods based on measurements of power or wind speed from individual wind turbine...

  2. Short-Circuit Current Analysis for DFIG Wind Farm Considering the Action of a Crowbar

    Directory of Open Access Journals (Sweden)

    Yan Hong Yuan

    2018-02-01

    Full Text Available With the increasing capacity of wind farms integrated into the power grid, the short-circuit current analysis for wind farms becomes more and more important. Since the wind turbine is usually integrated into the power grid via power electronic devices, the “crowbar” is installed in the wind turbine to protect the power electronic devices and to improve the fault ride through capability. The impact of the crowbar has to be considered during the short-circuit current analysis for the wind farm. In order to fully analyze the short-circuit current characteristics of a wind farm, the short-circuit currents for a doubly-fed induction generator (DFIG wind turbine under symmetrical and asymmetrical faults considering the crowbar action characteristic are derived firstly. Then the action situation of the crowbar of a DFIG wind turbine is studied and the action area curve is obtained. Taking the crowbar action, or not, as the grouping criterion, wind turbines in the wind farm are divided into two groups, and the wind farm is aggregated into two equivalent wind turbines. Using the equivalent model, the short-circuit current of a wind farm can be calculated accurately. Finally, simulations are performed in MATLAB/Simulink which is the commercial math software produced by the MathWorks company in Natick, Massachusetts, the United States to verify the proposed short-circuit current calculation method for the DFIG wind farm.

  3. Simulation of interaction between wind farm and power system[Flicker

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, P.; Hansen, A.; Janosi, L.; Bech, J.; Bak-Jensen, B.

    2001-12-01

    A dynamic model of the wind farm Hagesholm has been implemented in the dedicated power system simulation program DIgSILENT. The wind farm consists of six 2MW NM2000/72 wind turbines from NEG-Micon. The model has been verified using simultaneous power quality measurements on the 10 kV terminals of a single wind turbine and power performance measurements on two wind turbines. The verification shows a generally good agreement between simulations and measurements, although the simulations at higher wind speeds seem to underestimate the power and voltage fluctuations. A way to improve the simulation at higher wind speeds is suggested. (au)

  4. Wind Data Analysis and Wind Flow Simulation Over Large Areas

    Directory of Open Access Journals (Sweden)

    Terziev Angel

    2014-03-01

    Full Text Available Increasing the share of renewable energy sources is one of the core policies of the European Union. This is because of the fact that this energy is essential in reducing the greenhouse gas emissions and securing energy supplies. Currently, the share of wind energy from all renewable energy sources is relatively low. The choice of location for a certain wind farm installation strongly depends on the wind potential. Therefore the accurate assessment of wind potential is extremely important. In the present paper an analysis is made on the impact of significant possible parameters on the determination of wind energy potential for relatively large areas. In the analysis the type of measurements (short- and long-term on-site measurements, the type of instrumentation and the terrain roughness factor are considered. The study on the impact of turbulence on the wind flow distribution over complex terrain is presented, and it is based on the real on-site data collected by the meteorological tall towers installed in the northern part of Bulgaria. By means of CFD based software a wind map is developed for relatively large areas. Different turbulent models in numerical calculations were tested and recommendations for the usage of the specific models in flows modeling over complex terrains are presented. The role of each parameter in wind map development is made. Different approaches for determination of wind energy potential based on the preliminary developed wind map are presented.

  5. Patterns of migrating soaring migrants indicate attraction to marine wind farms.

    Science.gov (United States)

    Skov, Henrik; Desholm, Mark; Heinänen, Stefan; Kahlert, Johnny A; Laubek, Bjarke; Jensen, Niels Einar; Žydelis, Ramūnas; Jensen, Bo Præstegaard

    2016-12-01

    Monitoring of bird migration at marine wind farms has a short history, and unsurprisingly most studies have focused on the potential for collisions. Risk for population impacts may exist to soaring migrants such as raptors with K-strategic life-history characteristics. Soaring migrants display strong dependence on thermals and updrafts and an affinity to land areas and islands during their migration, a behaviour that creates corridors where raptors move across narrow straits and sounds and are attracted to islands. Several migration corridors for soaring birds overlap with the development regions for marine wind farms in NW Europe. However, no empirical data have yet been available on avoidance or attraction rates and behavioural reactions of soaring migrants to marine wind farms. Based on a post-construction monitoring study, we show that all raptor species displayed a significant attraction behaviour towards a wind farm. The modified migratory behaviour was also significantly different from the behaviour at nearby reference sites. The attraction was inversely related to distance to the wind farm and was primarily recorded during periods of adverse wind conditions. The attraction behaviour suggests that migrating raptor species are far more at risk of colliding with wind turbines at sea than hitherto assessed. © 2016 The Author(s).

  6. Hierarchical Communication Network Architectures for Offshore Wind Power Farms

    Directory of Open Access Journals (Sweden)

    Mohamed A. Ahmed

    2014-05-01

    Full Text Available Nowadays, large-scale wind power farms (WPFs bring new challenges for both electric systems and communication networks. Communication networks are an essential part of WPFs because they provide real-time control and monitoring of wind turbines from a remote location (local control center. However, different wind turbine applications have different requirements in terms of data volume, latency, bandwidth, QoS, etc. This paper proposes a hierarchical communication network architecture that consist of a turbine area network (TAN, farm area network (FAN, and control area network (CAN for offshore WPFs. The two types of offshore WPFs studied are small-scale WPFs close to the grid and medium-scale WPFs far from the grid. The wind turbines are modelled based on the logical nodes (LN concepts of the IEC 61400-25 standard. To keep pace with current developments in wind turbine technology, the network design takes into account the extension of the LNs for both the wind turbine foundation and meteorological measurements. The proposed hierarchical communication network is based on Switched Ethernet. Servers at the control center are used to store and process the data received from the WPF. The network architecture is modelled and evaluated via OPNET. We investigated the end-to-end (ETE delay for different WPF applications. The results are validated by comparing the amount of generated sensing data with that of received traffic at servers. The network performance is evaluated, analyzed and discussed in view of end-to-end (ETE delay for different link bandwidths.

  7. Power quality improvements of wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Soebrink, Kent H. [Eltra (Denmark); Stoeber, Ralf; Schettler, Frank; Bergmann, Klaus [Siemens (Germany); Jenkins, Nicholas; Ekanayake, Janaka; Saad-Saoud, Zouhir; Liboa, Maria Luiza; Strbac, Goran [UMIST (United Kingdom); Kaas Pedersen, Joergen; Helgesen Pedersen, Knud Ole [Technical Univ. of Denmark (Denmark)

    1998-06-01

    The main objective of the project was to investigate how the power quality of the electrical output of wind farms could be improved by the use of modern high power electronic technology. Although the research is of direct application to wind energy it will also be relevant to many other types of small-scale generation embedded in utility distribution networks. The operation of wind turbines with asynchronous generators requires reactive power which, if supplied form the network, leads to low voltages and increased losses. In order to improve the power factor of the generation, fixed capacitors are usually used to provide reactive power. However, if they are sized for the full requirement of the wind farm, they can cause self-excitation and potentially damaging and hazardous overvoltages if the wind turbines` connection with the network is interrupted and they become islanded. An advanced Static VAr Compensator (ASVC) uses a power electronic converter to generate or absorb reactive power. They can be used to provide reactive power with rapid control and with only modestly sized passive components (i.e. small capacitors and reactors). The objective of the project was to combine research and development of this novel form of electronic equipment with its application to increase the use of renewable energy, and wind power in particular, in the European Union. (EG) 19 refs.

  8. Coordinated Voltage Control of a Wind Farm based on Model Predictive Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Guo, Qinglai

    2016-01-01

    This paper presents an autonomous wind farm voltage controller based on Model Predictive Control (MPC). The reactive power compensation and voltage regulation devices of the wind farm include Static Var Compensators (SVCs), Static Var Generators (SVGs), Wind Turbine Generators (WTGs) and On...... are calculated based on an analytical method to improve the computation efficiency and overcome the convergence problem. Two control modes are designed for both voltage violated and normal operation conditions. A wind farm with 20 wind turbines was used to conduct case studies to verify the proposed coordinated...

  9. An Optimization Framework for Load and Power Distribution in Wind Farms

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal; Kanev, Stoyan

    2012-01-01

    The aim of this paper is to develop a controller for wind farms to optimize the load and power distribution. In this regard, the farm controller calculates the power reference signals for individual wind turbine controllers such that the sum of the power references tracks the power demanded...... by a system operator. Moreover, the reference signals are determined to reduce the load acting on wind turbines at low frequencies. Therefore, a trade-off is made for load and power control, which is formulated as an optimization problem. Afterwards, the optimization problem for the wind farm modeled...

  10. Planning and Development of Wind Farms: Wind Resource Assessment and Siting

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling

    These course notes are intended for the three-week course 45700 Planning and Development of Wind Farms given at the Technical University of Denmark. The purpose of the course notes is to give an introduction to wind resource assessment and siting issues using the WAsP suite of programs....

  11. Planning and Development of Wind Farms: Wind Resource Assessment and Siting

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling

    These course notes are intended for the three-week course 46200 Planning and Development of Wind Farms given at the Technical University of Denmark. The purpose of the course notes is to give an introduction to wind resource assessment and siting issues using the WAsP suite of programs....

  12. Offshore wind farms for hydrogen production subject to uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Kassem, Nabil [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Processes

    2002-07-01

    Wind power is a source of clean, nonpolluting electricity, which is fully competitive, if installed at favorable wind sites, with fossil fuel and nuclear power generation. Major technical growth has been in Europe, where government policies and high conventional energy costs favor the use of wind power. As part of its strategy, the EU-Commission has launched a target to increase the installed capacity of Wind power from 7 GWe, in 1998 to 40 GWe by year 2012. Wind power is an intermittent electricity generator, thus it does not provide electric power on an 'as needed' basis. Off-peak power generated from offshore wind farms can be utilized for hydrogen production using water electrolysis. Like electricity, hydrogen is a second energy carrier, which will pave the way for future sustainable energy systems. It is environmentally friendly, versatile, with great potentials in stationary and mobile power applications. Water electrolysis is a well-established technology, which depends on the availability of cheap electrical power. Offshore wind farms have longer lifetime due to lower mechanical fatigue loads, yet to be economic, they have to be of sizes greater than 150 MW using large turbines (> 1.5 MW). The major challenge in wind energy assessment is how accurately the wind speed and hence the error in wind energy can be predicted. Therefore, wind power is subject to a great deal of uncertainties, which should be accounted for in order to provide meaningful and reliable estimates of performance and economic figures-of-merit. Failure to account for uncertainties would result in deterministic estimates that tend to overstate performance and underestimate costs. This study uses methods of risk analysis to evaluate the simultaneous effect of multiple input uncertainties, and provide Life Cycle Assessment (LCA) of the-economic viability of offshore wind systems for hydrogen production subject to technical and economical uncertainties (Published in summary form only)

  13. Fishermen's Energy Atlantic City Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wissemann, Chris [Fishermen' s Atlantic City Windfarm, LLC, Atlantic City, NJ (United States)

    2017-05-04

    Fishermen's Energy Atlantic City Wind Farm final report under US DOE Advanced Technology Demonstration project documents achievements developing a demonstration scale offshore wind project off the coast of New Jersey.

  14. Active Power Dispatch Method for a Wind Farm Central Controller Considering Wake Effect

    DEFF Research Database (Denmark)

    Tian, Jie; Su, Chi; N. Soltani, Mohsen

    2014-01-01

    With the increasing integration of the wind power into the power system, wind farm are required to be controlled as a single unit and have all the same control tasks as conventional power plants. The wind farm central controller receives control orders from Transmission System Operator (TSO), the...... Optimization (PSO) is used to obtain the optimal wind power for each wind turbine. A case study is carried out. The available wind power of the wind farm was compared between the traditional dispatch method and the proposed dispatch method with the consideration of the wake effect....

  15. Evaluation of Quality of Life of Those Living near a Wind Farm.

    Science.gov (United States)

    Mroczek, Bożena; Banaś, Joanna; Machowska-Szewczyk, Małgorzata; Kurpas, Donata

    2015-05-29

    Health-related quality of life (HRQoL) can serve as a multidimensional means of evaluating the relationship between the presence of wind turbines in residential areas and their consequence for health. The purpose of this study was to determine whether a relationship exists between the presence of wind farms at different stages of development and the HRQoL of people living in their vicinity in Poland. The instruments employed in this study were the SF-36v2, a questionnaire measuring self-reported health problems, and a sociodemographic questionnaire. The study involved 1277 people who lived within 2 km from a wind turbine. The highest overall QoL scores were obtained by respondents living the closest to wind turbines. The mental health, role emotional, and social functioning scores were significantly higher among respondents living near wind farms and wind-farm construction sites than among those living close to locations where wind farms were planned but where construction had not yet begun. Positive correlations were found between physical and mental component scores and reactions to the news of plans to construct a wind farm. Significant differences in physical and mental component scores were observed between residents who reacted calmly and those who responded with apprehension. Residents who expected the improvement of their financial standing as a result of the wind farm assessed their general health higher than those who did not expect to receive any economic benefits. The lowest QoL scores corresponded to frequent headaches, stomach aches, and back pain over the previous three months, as well as recurrent problems with falling asleep, anxiety, and a lack of acceptance of the project. The lowest overall QoL and general health scores were noted among residents of places where wind-farm developments were either at the stage of planning or under construction. In order to find ways of reducing environmental stress and its adverse effects on health, it is

  16. Why the Coriolis force turns a wind farm wake clockwise in the Northern Hemisphere

    Directory of Open Access Journals (Sweden)

    M. P. van der Laan

    2017-05-01

    Full Text Available The interaction between the Coriolis force and a wind farm wake is investigated by Reynolds-averaged Navier–Stokes simulations, using two different wind farm representations: a high roughness and 5 × 5 actuator disks. Surprisingly, the calculated wind farm wake deflection is the opposite in the two simulations. A momentum balance in the cross flow direction shows that the interaction between the Coriolis force and the 5 × 5 actuator disks is complex due to turbulent mixing of veered momentum from above into the wind farm, which is not observed for the interaction between the Coriolis force and a roughness change. When the wind farm simulations are performed with a horizontally constant Coriolis force in order to isolate the effect of the wind veer, the wind farm wake deflection of the 5 × 5 actuator disks simulation remains unchanged. This proves that the present wind veer deflects the wind farm wake and not the local changes in the Coriolis force in the wake deficit region. An additional simulation of a single actuator disk, operating in a shallow atmospheric boundary layer, confirms that the Coriolis force indirectly turns a wind turbine wake clockwise, as observed from above, due to the presence of a strong wind veer.

  17. Life cycle assessment of the offshore wind farm alpha ventus

    International Nuclear Information System (INIS)

    Wagner, Hermann-Josef; Baack, Christoph; Eickelkamp, Timo; Epe, Alexa; Lohmann, Jessica; Troy, Stefanie

    2011-01-01

    Due to better wind conditions at sea, offshore wind farms have the advantage of higher electricity production compared to onshore and inland wind farms. In contrast, a greater material input, leading to increased energy consumptions and emissions during the production phase, is required to build offshore wind farms. These contrary effects are investigated for the first German offshore wind farm alpha ventus in the North Sea. In a life cycle assessment its environmental influence is compared to that of Germany's electricity mix. In comparison to the mix, alpha ventus had better indicators in nearly every investigated impact category. One kilowatt-hour electricity, generated by the wind farm, was burdened with 0.137 kWh Primary Energy-Equivalent and 32 g CO 2 -Equivalent, which represented only a small proportion of the accordant values for the mix. Furthermore, the offshore foundations as well as the submarine cable were the main energy intensive components. The energetic and greenhouse gas payback period was less than one year. Therefore, offshore wind power, even in deep water, is compatible with the switch to sustainable electricity production relying on renewable energies. Additional research, taking backup power plants as well as increasingly required energy storage systems into account, will allow further calculation. -- Highlights: → Offshore wind energy represents an environmentally friendly way of power generation. → The offshore foundations and the submarine cable are energy intensive components. → Alpha ventus emits 30 g CO 2 per kWh electricity over the entire life cycle. → Less specific emissions occur in comparison to the existing German electricity grid. → The energetic and greenhouse gas payback periods are less than one year.

  18. Willingness to pay for reduced visual disamenities from offshore wind farms in Denmark

    International Nuclear Information System (INIS)

    Ladenburg, Jacob; Dubgaard, Alex

    2007-01-01

    Expansion of offshore wind power plays a significant role in the energy policies of many EU countries. However, offshore wind farms create visual disamenities. These disamenities can be reduced by siting wind farms at larger distances from the coast-and accepting higher costs per kWh produced. In this paper willingness to pay for reducing the visual disamenities from future offshore wind farms is elicited using the economic valuation method Choice Experiments. The valuation scenario comprises the location of 720 offshore wind turbines (equivalent to 3600 MW) in farms at distances equal to: 12, 18 or 50 km from the shore, relative to an 8 km baseline. Using a fixed effect logit model average willingness to pay amounts were estimated as: 46, 96 and 122 Euros/household/year for having the wind farms located at 12, 18 and 50 km from the coast as opposed to 8 km. The results also reveal that WTP deviates significantly depending on the age of respondents and their experiences with offshore wind farms

  19. Study on offshore wind farm integration mode and reactive power compensation

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Xiaoyan; Hong, Lijun; Fu, Yang [Shanghai Univ. of Electrical Power (China). Power and Automation Engineering Dept.

    2013-07-01

    Two typical offshore wind farm grid-connected modes are introduced and dynamic characteristics under their modes are compared from the simulation by PSS/E. The result shows that offshore wind farm with VSC-HVDC has better dynamic characteristics on fault isolation, reactive power compensation, and fault ride through ability. In addition, STATCOM has been applied to the offshore wind farm, the simulation results indicates that it can improve the bus voltage stability in fault and maintain the voltage level under a small perturbation.

  20. Analysing wind farm efficiency on complex terrains

    DEFF Research Database (Denmark)

    Castellani, Francesco; Astolfi, Davide; Terzi, Ludovico

    2014-01-01

    The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representing...

  1. German support systems for onshore wind farms in the context of Polish acts limiting wind energy development

    Directory of Open Access Journals (Sweden)

    Dawid Leszek

    2017-09-01

    Full Text Available European energy system is undergoing a deep transition to low-emission energy sources, mainly wind farms. This transition is caused mostly by energy politics of European Union (EU and its goals in the topic of renewable energy. European wind energy is dominated by Germany that produces half of total wind energy in EU. The aim of this article is to present support systems for wind farms existing in Germany in the context of introducing in Poland the Act of 20 May 2016 on Wind Energy Investments limiting onshore wind farms localization and Act of 22 June 2016 introducing changes to the Act on Renewable Energy Sources (RES and some other acts. It is postulated to make amendments of acts regulating RES while considering German solutions.

  2. 基于等效风速的风电场等值建模%Equivalent model of wind farm By Using the Equivalent Wind Speed

    Institute of Scientific and Technical Information of China (English)

    严干贵; 李鸿博; 穆钢; 崔杨; 刘玉

    2011-01-01

    With the increasing scale of the integration of wind power into power grids,the influence of wind power fluctuation begins even more significant on the power system,and therefore the modeling of wind farms has become an important research topic.In this paper,a new equivalent model of wind farm is proposed to represent the collective behavior of all the generator units for large power systems simulations,instead of using a complete model of wind farms where all the wind turbines are modeled.The model proposed here is based on aggregating wind turbines into an equivalent wind turbine which receives an equivalent wind of the ones incident on the aggregated wind turbines and generates the same power as the sum of all the wind turbines.Among the possible wind combinations of all wind turbines,the wind which is the most relative with the output power of all the wind turbines selected as the equivalent wind,and the concept and the calculation method of wind energy conversion efficiency is also proposed.The equivalent model of a wind farm equipped with 58 doublyfed induction wind turbines is established using the method proposed here,and the output power of the wind farm is also calculated using the model and is compared with the actual value of the wind farm.The validity of the model is also verified.The proposed equivalent model can be used for fast calculation of the output power of wind farm with given wind conditions and suitable for large-scale simulation of.wind farm interconnection to power grids.%随着风电场联网规模的不断扩大,风电功率波动对电网影响愈加显著,风电场建模已成为一项重要研究课题。本文提出了用一台等值机来表征场内风电机组整体性能的风电场等值模型,该等值机

  3. Offshore wind farms in the local community - a survey at Horns Rev wind farm. Background report; Havvindmoeller i lokalomraedet - en undersoegelse ved Horns Rev havmoellepark. Baggrundsrapport

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, S.

    2005-07-15

    This report is part of a socio-economic project about offshore wind farms' influence on the local community. The project is part of the monitoring programme in connection with the establishment of the offshore wind farms at Horns Rev and Nysted. The socio-economic project consists of a sociological and an environment-economic project. This report is part of the sociological project which has the purpose of identifying attitudes towards the wind farm before and after the erection with a view to identify possible changes in opinions and reasons for these changes. (BA)

  4. Transient Stability Assessment of Power System with Large Amount of Wind Power Penetration

    DEFF Research Database (Denmark)

    Liu, Leo; Chen, Zhe; Bak, Claus Leth

    2012-01-01

    Recently, the security and stability of power system with large amount of wind power are the concerned issues, especially the transient stability. In Denmark, the onshore and offshore wind farms are connected to distribution system and transmission system respectively. The control and protection...... methodologies of onshore and offshore wind farms definitely affect the transient stability of power system. In this paper, the onshore and offshore wind farms are modeled in detail in order to assess the transient stability of western Danish power system. Further, the computation of critical clearing time (CCT...... plants, load consumption level and high voltage direct current (HVDC) transmission links are taken into account. The results presented in this paper are able to provide an early awareness of power system security condition of the western Danish power system....

  5. Statistical Analysis and Comparison of Harmonics Measured in Offshore Wind Farms

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2011-01-01

    The paper shows statistical analysis of harmonic components measured in different offshore wind farms. Harmonic analysis is a complex task and requires many aspects, such as measurements, data processing, modeling, validation, to be taken into consideration. The paper describes measurement process...... and shows sophisticated analysis on representative harmonic measurements from Avedøre Holme, Gunfleet Sands and Burbo Bank wind farms. The nature of generation and behavior of harmonic components in offshore wind farms clearly presented and explained based on probabilistic approach. Some issues regarding...... commonly applied standards are also put forward in the discussion. Based on measurements and data analysis it is shown that a general overview about wind farm harmonic behaviour cannot be fully observed only based on single-value measurements as suggested in the standards but using more descriptive...

  6. Neighborhood Effects in Wind Farm Performance: A Regression Approach

    Directory of Open Access Journals (Sweden)

    Matthias Ritter

    2017-03-01

    Full Text Available The optimization of turbine density in wind farms entails a trade-off between the usage of scarce, expensive land and power losses through turbine wake effects. A quantification and prediction of the wake effect, however, is challenging because of the complex aerodynamic nature of the interdependencies of turbines. In this paper, we propose a parsimonious data driven regression wake model that can be used to predict production losses of existing and potential wind farms. Motivated by simple engineering wake models, the predicting variables are wind speed, the turbine alignment angle, and distance. By utilizing data from two wind farms in Germany, we show that our models can compete with the standard Jensen model in predicting wake effect losses. A scenario analysis reveals that a distance between turbines can be reduced by up to three times the rotor size, without entailing substantial production losses. In contrast, an unfavorable configuration of turbines with respect to the main wind direction can result in production losses that are much higher than in an optimal case.

  7. Optimized dispatch of wind farms with power control capability for power system restoration

    DEFF Research Database (Denmark)

    Xie, Yunyun; Liu, Changsheng; Wu, Qiuwei

    2017-01-01

    As the power control technology of wind farms develops, the output power of wind farms can be constant, which makes it possible for wind farms to participate in power system restoration. However, due to the uncertainty of wind energy, the actual output power can’t reach a constant dispatch power...... in all time intervals, resulting in uncertain power sags which may induce the frequency of the system being restored to go outside the security limits. Therefore, it is necessary to optimize the dispatch of wind farms participating in power system restoration. Considering that the probability...... distribution function (PDF) of transient power sags is hard to obtain, a robust optimization model is proposed in this paper, which can maximize the output power of wind farms participating in power system restoration. Simulation results demonstrate that the security constraints of the restored system can...

  8. Practical difficulties in raising finance for wind farms

    International Nuclear Information System (INIS)

    Johns, J.H.

    1995-01-01

    The 15 year term of NFFO3 will significantly alter the financial structures of wind farm projects. Senior debt terms will extend to 10-12 years and returns are unlikely to reach the levels required by venture capitalists. Returns to equity investors can be enhanced by debt and equity gearing techniques, for example the introduction of preference shares. Two investment schemes and an additional capital gains relief which were introduced in the November 1993 budget could benefit potential investors in wind farms. (Author)

  9. Analysis of superconducting magnetic energy storage applications at a proposed wind farm site near Browning, Montana

    Science.gov (United States)

    Gaustad, K. L.; Desteese, J. G.

    1993-07-01

    A computer program was developed to analyze the viability of integrating superconducting magnetic energy storage (SMES) with proposed wind farm scenarios at a site near Browning, Montana. The program simulated an hour-by-hour account of the charge/discharge history of a SMES unit for a representative wind-speed year. Effects of power output, storage capacity, and power conditioning capability on SMES performance characteristics were analyzed on a seasonal, diurnal, and hourly basis. The SMES unit was assumed to be charged during periods when power output of the wind resource exceeded its average value. Energy was discharged from the SMES unit into the grid during periods of low wind speed to compensate for below-average output of the wind resource. The option of using SMES to provide power continuity for a wind farm supplemented by combustion turbines was also investigated. Levelizing the annual output of large wind energy systems operating in the Blackfeet area of Montana was found to require a storage capacity too large to be economically viable. However, it appears that intermediate-sized SMES economically levelize the wind energy output on a seasonal basis.

  10. Optimization of rotating equipment in offshore wind farm

    International Nuclear Information System (INIS)

    Okunade, O A

    2014-01-01

    The paper considered the improvement of rotating equipment in a wind farm, and how these could maximise the farm power capacity. It aimed to increase capacity of electricity generation through a renewable source in UK and contribute to 15 per cent energy- consumption target, set by EU on electricity through renewable sources by 2020. With reference to a case study in UK offshore wind farm, the paper analysed the critique of the farm, as a design basis for its optimization. It considered power production as design situation, load cases and constraints, in order to reflect characteristics and behaviour of a standard design. The scope, which considered parts that were directly involved in power generation, covered rotor blades and the impacts of gearbox and generator to power generation. The scope did not however cover support structures like tower design. The approaches of detail data analysis of the blade at typical wind load conditions, were supported by data from acceptable design standards, relevant authorities and professional bodies. The findings in proposed model design showed at least over 3 per cent improvement on the existing electricity generation. It also indicated overall effects on climate change

  11. Optimization of rotating equipment in offshore wind farm

    Science.gov (United States)

    Okunade, O. A.

    2014-07-01

    The paper considered the improvement of rotating equipment in a wind farm, and how these could maximise the farm power capacity. It aimed to increase capacity of electricity generation through a renewable source in UK and contribute to 15 per cent energy- consumption target, set by EU on electricity through renewable sources by 2020. With reference to a case study in UK offshore wind farm, the paper analysed the critique of the farm, as a design basis for its optimization. It considered power production as design situation, load cases and constraints, in order to reflect characteristics and behaviour of a standard design. The scope, which considered parts that were directly involved in power generation, covered rotor blades and the impacts of gearbox and generator to power generation. The scope did not however cover support structures like tower design. The approaches of detail data analysis of the blade at typical wind load conditions, were supported by data from acceptable design standards, relevant authorities and professional bodies. The findings in proposed model design showed at least over 3 per cent improvement on the existing electricity generation. It also indicated overall effects on climate change.

  12. Initial results of local grid control using wind farms with grid support

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Iov, F.; Blaabjerg, F.

    2005-09-01

    This report describes initial results with simulation of local grid control using wind farms with grid support. The focus is on simulation of the behaviour of the wind farms when they are isolated from the main grid and establish a local grid together with a few other grid components. The isolated subsystems used in the work presented in this report do not intend to simulate a specific subsystem, but they are extremely simplified single bus bar systems using only a few more components than the wind farm. This approach has been applied to make it easier to understand the dynamics of the subsystem. The main observation is that the fast dynamics of the wind turbines seem to be able to contribute significantly to the grid control, which can be useful where the wind farm is isolated with a subsystem from the main grid with surplus of generation. Thus, the fast down regulation of the wind farm using automatic frequency control can keep the subsystem in operation and thereby improve the reliability of the grid. (LN)

  13. Actuator disk model of wind farms based on the rotor average wind speed

    DEFF Research Database (Denmark)

    Han, Xing Xing; Xu, Chang; Liu, De You

    2016-01-01

    Due to difficulty of estimating the reference wind speed for wake modeling in wind farm, this paper proposes a new method to calculate the momentum source based on the rotor average wind speed. The proposed model applies volume correction factor to reduce the influence of the mesh recognition of ...

  14. Fatigue distribution optimization for offshore wind farms using intelligent agent control

    DEFF Research Database (Denmark)

    Zhao, Rongyong; Shen, Wen Zhong; Knudsen, Torben

    2012-01-01

    with its neighbouring downwind turbines and organizes them adaptively into a wind delivery group along the wind direction. The agent attributes and the event structure are designed on the basis of the intelligent agent theory by using the unified modelling language. The control strategy of the intelligent......A novel control approach is proposed to optimize the fatigue distribution of wind turbines in a large‐scale offshore wind farm on the basis of an intelligent agent theory. In this approach, each wind turbine is considered to be an intelligent agent. The turbine at the farm boundary communicates...... coefficient for every wind turbine. The optimization is constrained such that the average fatigue for every turbine is smaller than what would be achieved by conventional dispatch and such that the total power loss of the wind farm is restricted to a few percent of the total power. This intelligent agent...

  15. Wind power: a guide for farms and rural businesses

    International Nuclear Information System (INIS)

    1998-03-01

    This Guide is mainly concerned with single wind turbines rather than large windfarms, concentrating on the opportunities for existing businesses and new partnerships to gain value from their own local wind resource. There is a wide range of types of business that can use windpower and there are many types of application. Heavy power users are good candidates, and these include intensive livestock farms, feed mills, distilleries, vegetable cold stores, food and fish processing factories, quarries, tourist and leisure complexes, and so on. There are also many cases where using wind power is the least expensive of a number of costly options, for example where the grid is inaccessible; wind power can be used to supply heat and to pump water. The aim of this Guide is to illustrate and explain these uses, and to place them firmly in the context of business opportunity for rural areas. (author)

  16. Improved Relay Node Placement Algorithm for Wireless Sensor Networks Application in Wind Farm

    DEFF Research Database (Denmark)

    Chen, Qinyin; Hu, Y.; Chen, Zhe

    2013-01-01

    -tolerance. Each wind turbine has a potentially large number of data points needing to be monitored and collected, as farms continue to increase in scale; distances between turbines can reach several hundred meters. Optimal placement of relays in a large farm requires an efficient algorithmic solution. A relay...... node placement algorithm is proposed in this paper to approximate the optimal position for relays connecting each turbine. However, constraints are then required to prevent relay nodes being overloaded in 3-dimensions. The algorithm is extended to 3-dimensional Euclidean space for this optimal relay...

  17. Wind Farm Control Survey

    DEFF Research Database (Denmark)

    Knudsen, Torben; Bak, Thomas; Svenstrup, Mikael

    2013-01-01

    This document is a delivery in the project NORCOWE. It is part of work package WP3.2.2. The main goal is to establish the present state-of-the-art for wind farm control for both research and practice. The main approach will be to study the literature. This will of cause be much more efficient...... for the research part than for the practice part. It is however not the intention to do company interviews or similar. This report is structured into a section for each WF control objective. These sections then includes the important control project issues: choice of input and output, control method, and modelling...... turbine farm based on a dynamic programming type of method....

  18. Wind farm turbulence impacts on general aviation airports in Kansas : [technical summary].

    Science.gov (United States)

    2014-01-01

    Wind turbines and wind farms have become popular in the State of Kansas. Some general aviation : pilots have expressed a concern about the turbulence that the spinning blades are creating. If a : wind farm is built near an airport, does this affect t...

  19. New grid-planning and certification approaches for the large-scale offshore-wind farm grid-connection systems

    Energy Technology Data Exchange (ETDEWEB)

    Heising, C.; Bartelt, R. [Avasition GmbH, Dortmund (Germany); Zadeh, M. Koochack; Lebioda, T.J.; Jung, J. [TenneT Offshore GmbH, Bayreuth (Germany)

    2012-07-01

    Stable operation of the offshore-wind farms (OWF) and stable grid connection under stationary and dynamic conditions are essential to achieve a stable public power supply. To reach this aim, adequate grid-planning and certification approaches are a major advantage. Within this paper, the fundamental characteristics of the offshore-wind farms and their grid-connection systems are given. The main goal of this research project is to study the stability of the offshore grid especially in terms of subharmonic stability for the likely future extension stage of the offshore grids i.e. having parallel connection of two or more HVDC links and for certain operating scenarios e.g. overload scenario. The current requirements according to the grid code are not the focus of this research project. The goal is to study and define potential additional grid code requirements, simulations, tests and grid planning methods for the future. (orig.)

  20. A semi-parabolic wake model for large offshore wind farms based on the open source CFD solver OpenFOAM

    Directory of Open Access Journals (Sweden)

    Cabezón D.

    2014-01-01

    Full Text Available Wake effect represents one of the main sources of energy loss and uncertainty when designing offshore wind farms. Traditionally analytical models have been used to optimize and estimate power deficits. However these models have shown to underestimate wake effect and consequently overestimate output power [1, 2]. This means that analytical models can be very helpful at optimizing preliminary layouts but not as accurate as needed for an ultimate fine design. Different techniques can be found in the literature to study wind turbine wakes that include simplified kinematic models and more advanced field models, that solve flow equations with different turbulence closure schemes. See the review papers of Crespo et al. [3], Vermeer et al. [4], and Sanderse et al. [5]. Purely elliptic Computational Fluid Dynamics (CFD models based on the actuator disk technique have been developed during the last years [6–8]. They consider wind turbine rotor as a disk where a distribution of axial forces act over the incoming air. It is a fair approach but it can still be computationally expensive for big wind farms in an operative mode. With this technique still active, an alternative approach inspired on the parabolic wake models [9, 10] is proposed. Wind turbine rotors continue to be represented as actuator disks but now the domain is split into subdomains containing one or more wind turbines. The output of each subdomain is mapped onto the input boundary of the next one until the end of the domain is reached, getting a considerable decrease on computational time, by a factor of order 10. As the model is based on the open source CFD solver OpenFOAM, it can be parallelized to speed-up convergence. The near wake is calculated so no initial wind speed deficit profiles have to be supposed as in totally parabolic models and alternative turbulence models, such as the anisotropic Reynolds Stress Model (RSM can be used. Traditional problems of elliptic models related to

  1. Wind energy power plants (wind farms) review and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Newbold, K B; McKeary, M [McMaster Univ., Hamilton, ON (Canada). McMaster Inst. of Environment and Health

    2010-07-01

    Global wind power capacity has increased by an average cumulative rate of over 30 percent over the past 10 years. Although wind energy emits no air pollutants and facilities can often share spaces with other activities, public opposition to wind power development is an ongoing cause of concern. Development at the local level in Ontario has been met with fierce opposition on the basis of health concerns, aesthetic values, potential environmental impacts, and economic risks. This report was prepared for the Town of Wasaga Beach, and examined some of the controversy surrounding wind power developments through a review of evidence found in the scientific literature. The impacts of wind power developments related to noise, shadow flicker, avian mortality, bats, and real estate values were evaluated. The study included details of interviews conducted with individuals from Ontario localities where wind farms were located. 77 refs., 1 tab., 1 fig., 2 appendices.

  2. Wind energy assessment and wind farm simulation in Triunfo - Pernambuco, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Laerte; Filho, Celso

    2010-09-15

    The Triunfo wind's characterization, in Pernambuco state, situated in Brazilian northeast, and wind power potential assessment study shows a average wind speed of 11.27 m / s, predominant Southeast wind direction, average wind power density of 1672 W/m2 and Weibull parameters shape and scale equal to 2,0 and 12,7 m/s. The wind farm was simulated by using 850kW wind turbines (total of 20MW). The simulated shows AEP of 111,4 GWh, Cf of 62% and 5462 hours of operation by year. The economical simulated results, shows Pay-back of 3 years, TIR = 47% and VAN = 85.506kEuro booths @ 20 years time period.

  3. Wind Power in Electrical Distribution Systems

    DEFF Research Database (Denmark)

    Chen, Zhe

    2013-01-01

    Recent years, wind power is experiencing a rapid growth, large number of wind turbines/wind farms have been installed and connected to power systems. In addition to the large centralised wind farms connected to transmission grids, many distributed wind turbines and wind farms are operated as dist...

  4. Effects of wind farms on harbour porpoise behaviour and population dynamics

    DEFF Research Database (Denmark)

    Nabe-Nielsen, Jacob; Tougaard, Jakob; Teilmann, Jonas

    We developed an individual-based simulation model in order to study the cumulative impacts of wind farms and ship traffic on the long-term survival and population dynamics of the harbour porpoise (Phocoena phocoena) in Kattegat and the Belt Seas. The model is based on knowl- edge of the porpoises...... at distances >1 km. Our simulations suggest that operating wind farms and wind farms under construction do not affect the size or dynamics of the harbour porpoise population in Kattegat. Ship traffic may, in contrast, cause the population size to decrease....

  5. Stochastic Prediction of Wind Generating Resources Using the Enhanced Ensemble Model for Jeju Island’s Wind Farms in South Korea

    Directory of Open Access Journals (Sweden)

    Deockho Kim

    2017-05-01

    Full Text Available Due to the intermittency of wind power generation, it is very hard to manage its system operation and planning. In order to incorporate higher wind power penetrations into power systems that maintain secure and economic power system operation, an accurate and efficient estimation of wind power outputs is needed. In this paper, we propose the stochastic prediction of wind generating resources using an enhanced ensemble model for Jeju Island’s wind farms in South Korea. When selecting the potential sites of wind farms, wind speed data at points of interest are not always available. We apply the Kriging method, which is one of spatial interpolation, to estimate wind speed at potential sites. We also consider a wind profile power law to correct wind speed along the turbine height and terrain characteristics. After that, we used estimated wind speed data to calculate wind power output and select the best wind farm sites using a Weibull distribution. Probability density function (PDF or cumulative density function (CDF is used to estimate the probability of wind speed. The wind speed data is classified along the manufacturer’s power curve data. Therefore, the probability of wind speed is also given in accordance with classified values. The average wind power output is estimated in the form of a confidence interval. The empirical data of meteorological towers from Jeju Island in Korea is used to interpolate the wind speed data spatially at potential sites. Finally, we propose the best wind farm site among the four potential wind farm sites.

  6. Dynamic Reactive Power Compensation of Large Scale Wind Integrated Power System

    DEFF Research Database (Denmark)

    Rather, Zakir Hussain; Chen, Zhe; Thøgersen, Paul

    2015-01-01

    wind turbines especially wind farms with additional grid support functionalities like dynamic support (e,g dynamic reactive power support etc.) and ii) refurbishment of existing conventional central power plants to synchronous condensers could be one of the efficient, reliable and cost effective option......Due to progressive displacement of conventional power plants by wind turbines, dynamic security of large scale wind integrated power systems gets significantly compromised. In this paper we first highlight the importance of dynamic reactive power support/voltage security in large scale wind...... integrated power systems with least presence of conventional power plants. Then we propose a mixed integer dynamic optimization based method for optimal dynamic reactive power allocation in large scale wind integrated power systems. One of the important aspects of the proposed methodology is that unlike...

  7. Mapping seabird sensitivity to offshore wind farms.

    Science.gov (United States)

    Bradbury, Gareth; Trinder, Mark; Furness, Bob; Banks, Alex N; Caldow, Richard W G; Hume, Duncan

    2014-01-01

    We present a Geographic Information System (GIS) tool, SeaMaST (Seabird Mapping and Sensitivity Tool), to provide evidence on the use of sea areas by seabirds and inshore waterbirds in English territorial waters, mapping their relative sensitivity to offshore wind farms. SeaMaST is a freely available evidence source for use by all connected to the offshore wind industry and will assist statutory agencies in assessing potential risks to seabird populations from planned developments. Data were compiled from offshore boat and aerial observer surveys spanning the period 1979-2012. The data were analysed using distance analysis and Density Surface Modelling to produce predicted bird densities across a grid covering English territorial waters at a resolution of 3 km×3 km. Coefficients of Variation were estimated for each grid cell density, as an indication of confidence in predictions. Offshore wind farm sensitivity scores were compiled for seabird species using English territorial waters. The comparative risks to each species of collision with turbines and displacement from operational turbines were reviewed and scored separately, and the scores were multiplied by the bird density estimates to produce relative sensitivity maps. The sensitivity maps reflected well the amassed distributions of the most sensitive species. SeaMaST is an important new tool for assessing potential impacts on seabird populations from offshore development at a time when multiple large areas of development are proposed which overlap with many seabird species' ranges. It will inform marine spatial planning as well as identifying priority areas of sea usage by marine birds. Example SeaMaST outputs are presented.

  8. Offshore wind farms in the local environment - an examination at Horns Rev Offshore Wind Farm. Background report; Havvindmoeller i lokalomraadet - en undersoegelse ved Horns Rev Havmoellepark. Baggrundsrapport

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Susanne

    2005-07-01

    Horns Rev Offshore Wind Farm was built in 2002. A presentation is made of a sociological, qualitative survey on the local community's reception of the offshore wind farm. The survey aims at identifying attitudes towards the farm before and after the construction, with a view to identifying possible changes in attitudes, and explain the reasons for these (ml)

  9. Wind farms impact on radar aviation interests - final report

    Energy Technology Data Exchange (ETDEWEB)

    Poupart, G.J.

    2003-09-01

    The main objectives of the study were: to determine the effects of siting wind turbines adjacent to primary air traffic control radar; to gather the information required for the generation of guidelines by civil, military and wind farm developer stakeholders; to determine the extent to which the design of wind turbines influences their effects on radar systems and to determine the extent to which design of the radar processing influences the effects of wind turbines on radar systems. A computer model was developed to predict the Radar Cross Section (RCS) of wind turbines and understand the interaction of radar energy and turbines. The model was designed to predict and simulate the impact of wind farms on the primary radar display. Validation of the model was carried out in a full-scale trial and modelling process, with data collected from a number of sources. The model was validated against a single turbine scenario and showed an accurate prediction capability. Further validation of the model could be gained through a multiple turbine trial. The knowledge gained from the development and validation of the predictive computer model has been used to conduct a sensitivity analysis (of the sub-elements of the radar and wind farm interaction) and to compile a list of the key factors influencing the radar signature of wind turbines. The result is a more detailed quantification of the complex interactions between wind turbines and radar systems than was previously available. The key findings of how the design, size and construction materials of wind turbines affect RCS are summarised.

  10. Transmission of wave energy through an offshore wind turbine farm

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Johnson, Martin; Sørensen, Ole Rene

    2013-01-01

    condition at infinity. From airborne and Satellite SAR (Synthetic Aperture Radar) a model has been derived for the change of the water surface friction C) inside and on the lee side of the offshore wind farm. The effects have been implemented in a spectral wind wave model,MIKE21 SW, and a parametric study......The transmission of wave energy passing an offshore wind farm is studied. Three effects that can change the wave field are analysed, which is the A) energy dissipation due to drag resistance, B) wave reflection/diffraction from structures, and C) the effect of a modified wind field inside...... and on the lee side of the wind farm. The drag dissipation, A), is quantified by a quadratic resistance law. The effect of B) is parameterised based on 1st order potential theory. A method to find the amount of reflected and transmitted wave energy is developed based on the panel method WAMIT™ and a radiation...

  11. Effect of Tower Shadow and Wind Shear in a Wind Farm on AC Tie-Line Power Oscillations of Interconnected Power Systems

    DEFF Research Database (Denmark)

    Tan, Jin; Hu, Weihao; Wang, Xiaoru

    2013-01-01

    This paper describes a frequency domain approach for evaluating the impact of tower shadow and wind shear effects (TSWS) on tie-line power oscillations. A simplified frequency domain model of an interconnected power system with a wind farm is developed. The transfer function, which relates the tie......-line power variation to the mechanical power variation of a wind turbine, and the expression of the maximum magnitude of tie-line power oscillations are derived to identify the resonant condition and evaluate the potential risk. The effects of the parameters on the resonant magnitude of the tie-line power...... are also discussed. The frequency domain analysis reveals that TSWS can excite large tie-line power oscillations if the frequency of TSWS approaches the tie-line resonant frequency, especially in the case that the wind farm is integrated into a relatively small grid and the tie-line of the interconnected...

  12. An economic assessment of tropical cyclone risk on offshore wind farms

    DEFF Research Database (Denmark)

    Hong, Lixuan; Möller, Bernd

    2012-01-01

    and cost and setting design parameters for offshore wind turbines are then discussed. The impact of tropical cyclones on offshore wind farms likes a double-edged sword, which might be advantageous for some regions in terms of increasing full-loaded hours of turbines, but also disadvantageous for others due....... A probabilistic tropical cyclone event model is applied to evaluate 20-year, 30-year, 50-year and 100-year recurrence of extreme wind speeds by geographical location. Combining a damage model derived from empirical loss data and an investment cost model within a Geographical Information System (GIS), the annual...... to its destructive effects. However, specific design standards and insurance of turbines would help reduce risks and economic losses of offshore wind farms in tropical cyclone-prone areas and expand exploitable locations for future offshore wind farms....

  13. Hard bottom substrate monitoring Horns Rev offshore wind farm. Annual status report 2003

    Energy Technology Data Exchange (ETDEWEB)

    Leonhard, S.B.; Pedersen, John

    2004-05-15

    Elsam and Eltra built the offshore demonstration wind farm at Horns Rev in the North Sea. Elsam is the owner and is responsible for the operation of the wind farm. Eltra is responsible for the connection of the wind farm to the national onshore grid. In the summer months of 2002, Elsam constructed the world's largest offshore wind farm off the Danish west coast. The wind farm is sited 14-20 km into the North Sea, west of Blaevands Huk. The first wind turbine was erected in May 2002 and the last wind turbine tower of a total of 80 was in place by August 2002. The construction work was completed with the last connecting cables sluiced down in September 2002. All the wind turbines were in production by December 2002. The expected impact of the wind farm will primarily be an alternation of habitats due to the introduction of hard bottom substrates as wind turbine towers and scour protections. A continuous development in the epifouling communities will be expected together with an introduction of new or alien species in the area. The indigenous benthic community in the area of Horns Rev can be characterised by infauna species belonging to the Goniadella-Spisula community. This community is typical of sandbanks in the North Sea area, although communities in such areas are very variable and site-specific. Character species used as indicators for environmental changes in the Horns Rev area are the bristle worms Goniadella bobretzkii, Ophelia borealis, Psione remota and Orbinia sertulata and the mussels Goodallia triangularis and Spisula solida. In connection with the implementation of the monitoring programme concerning the ecological impact of the introduction of hard substrate related to the Horns Rev Wind Farm, surveys on hard bottom substrate was conducted in March 2003 and in September 2003. This report describes the first year results of surveys on hard substrate after the completion of the offshore wind farm at Horns Rev. (au)

  14. How neighbours of the first large Swiss wind farm perceive the wind turbines; Du vent dans les pales. Experiences et perceptions des eoliennes par les habitants de la region du Mont-Crosin

    Energy Technology Data Exchange (ETDEWEB)

    Droz, Y; Mieville-Ott, V; Monsutti, A

    2003-07-01

    This report for the Swiss Federal Office of Energy presents the results of a study on the way the neighbours of the first large Swiss wind farm react on this particular neighbourhood. A survey involving 421 people showed that, as a general rule, the wind turbines are well accepted. However, it also showed that a transparent negotiation with the population during wind turbine project developpement is absolutely needed. Public acceptance also depends on the way the turbine arrays are aesthetically integrated in the landscape. The report is rounded up by recommendations for companies in charge of wind energy projects in order to minimize troubles with the concerned population. For example, financial compensation could be a suitable means when dealing with farmers.

  15. Wind Conditions for Wind Farm Hanstholm

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Hahmann, Andrea N.; Mann, Jakob

    The net annual energy production (AEP) of the Hanstholm Wind Farm is 158 GWh per year for the Siemens SWT-3.6-120 turbine and 140 GWh for the Vestas V112-3.0 turbine. These values have an uncertainty (standard deviation) of 6%. This result is mainly based on the data for Risø DTU’s test station...... at Høvsøre where wind speeds are measured at approximately the same height as the turbines at Hanstholm and where the terrain is similar. On top of that meso-scale modeling has been used to extrapolate the climatology from Høvsøre to Hanstholm increasing the AEP by almost 6% compared to just using...... the Høvsøre climatology directly. This method of extrapolation is rather new, but several older investigations indicate that the wind resource at Hanstholm is slightly higher than at Høvsøre. The work is carried out for Grontmij-Carl Bro according to a contract dated January 18th 2011....

  16. Use of wind pumps in Indian farms: A point of view

    International Nuclear Information System (INIS)

    Tewari, S.K.

    1991-01-01

    This presentation is aimed at critically reviewing the experiences under several organized efforts to harness wind energy for water lifting for irrigation use in India. This is viewed with the overall objective that wind energy devices should be seen operating in good numbers in farms in a reliable and cost-effective manner. The focus is on irrigation in farms using pumped water, which could generate a fairly large demand for wind pumps. The quantity of pumped water required for irrigation is at least one order of magnitude higher compared to its demand from domestic and industrial uses in urban areas. With respect to the hardware India has a broad experience that goes back to the mid-fifties, when the first classic multi-blades were imported. The tests and experiments, beginning in the early sixties, include a.o. imported classic multi-blades, modified locally produced multi-blades, modern wind pumps without gearbox (12PU500), sail windmills and rotary pumps. A 1983 study showed that in certain regions in India irrigation with wind pumps can be economically more viable than other renewable and conventional alternatives. The conclusions of this study still have to be confirmed by field studies. Although the government shows great interest in the exploitation of the wind energy potential, one of the main problems seems how to get the government interested in the most viable wind energy applications. 1 ill., 1 tab

  17. Expected Effects of Offshore Wind Farms on Mediterranean Marine Life

    Directory of Open Access Journals (Sweden)

    Laura Bray

    2016-03-01

    Full Text Available Current climate policy and issues of energy security mean wind farms are being built at an increasing rate to meet energy demand. As wind farm development is very likely in the Mediterranean Sea, we provide an assessment of the offshore wind potential and identify expected biological effects of such developments in the region. We break new ground here by identifying potential offshore wind farm (OWF “hotspots” in the Mediterranean. Using lessons learned in Northern Europe, and small-scale experiments in the Mediterranean, we identify sensitive species and habitats that will likely be influenced by OWFs in both these hotspot areas and at a basin level. This information will be valuable to guide policy governing OWF development and will inform the industry as and when environmental impact assessments are required for the Mediterranean Sea.

  18. Hydrogen Gas Production in a Stand-Alone Wind Farm

    Directory of Open Access Journals (Sweden)

    M. Naziry Kordkandy

    2017-04-01

    Full Text Available This paper is analyzing the operation of a stand-alone wind farm with variable speed turbines, permanent magnet synchronous generators (PMSG and a system for converting wind energy during wind speed variations. On this paper, the design and modeling of a wind system which uses PMSG’s to provide the required power of a hydrogen gas electrolyzer system, is discussed. This wind farm consists of three wind turbines, boost DC-DC converters, diode full bridge rectifiers, permanent magnet synchronous generators, MPPT control and a hydrogen gas electrolyzer system. The MPPT controller based on fuzzy logic is designed to adjust the duty ratio of the boost DC-DC converters to absorb maximum power. The proposed fuzzy logic controller assimilates, with (PSF MPPT algorithm which generally used to absorb maximum power from paralleled wind turbines and stores it in form of hydrogen gas. The system is modeled and its behavior is studied using the MATLAB software.

  19. Spatial structure of kinetic energy spectra in LES simulations of flow in an offshore wind farm

    Science.gov (United States)

    Fruh, Wolf-Gerrit; Creech, Angus

    2017-04-01

    The evolution of wind turbine and wind farm wakes was investigated numerically for the case of Lillgrund wind farm consisting of a tightly packed array of 48 turbines. The simulations for a number of wind directions at a free wind speed of just under the rated wind speed in a neutrally stable atmosphere were carried out using Large-Eddy Simulations with the adaptive Finite-Element CFD solver Fluidity. The results were interpolated from the irregularly spaced mesh nodes onto a regular grid with comparable spatial resolution at horizontal slices at various heights. To investigate the development of the wake as the flow evolves through the array, spectra of the kinetic energy in sections perpendicular to the wind directions within the wake and to the sides of the array were calculated. This paper will present the key features and spectral slopes of the flow as a function of downstream distance from the front turbine through and beyond the array. The main focus will be on the modification of the spectra as the flow crosses a row of turbines followed by its decay in the run-up to the next row, but we will also present to wake decay of the wind farm wake downstream of the array.

  20. Assessing the impact of marine wind farms on birds through movement modelling.

    Science.gov (United States)

    Masden, Elizabeth A; Reeve, Richard; Desholm, Mark; Fox, Anthony D; Furness, Robert W; Haydon, Daniel T

    2012-09-07

    Advances in technology and engineering, along with European Union renewable energy targets, have stimulated a rapid growth of the wind power sector. Wind farms contribute to carbon emission reductions, but there is a need to ensure that these structures do not adversely impact the populations that interact with them, particularly birds. We developed movement models based on observed avoidance responses of common eider Somateria mollissima to wind farms to predict, and identify potential measures to reduce, impacts. Flight trajectory data that were collected post-construction of the Danish Nysted offshore wind farm were used to parameterize competing models of bird movements around turbines. The model most closely fitting the observed data incorporated individual variation in the minimum distance at which birds responded to the turbines. We show how such models can contribute to the spatial planning of wind farms by assessing their extent, turbine spacing and configurations on the probability of birds passing between the turbines. Avian movement models can make new contributions to environmental assessments of wind farm developments, and provide insights into how to reduce impacts that can be identified at the planning stage.

  1. Emerging practices of wind farm planning in a dense bird migration area

    DEFF Research Database (Denmark)

    Clausen, Niels-Erik; Mortensen, N.G.; Hansen, J.C.

    2003-01-01

    The objective of this paper is to present part of The Wind Atlas for Egypt project aiming at developing a firm basis for planning and utilization of the vast wind energy resources available in Egypt. The project should recommend a common planning framework for wind farm development in Egypt...... is briefly introduced. As a case study to illustrate the planning process a 60 MW wind farm located at the Gulf of El-Zayt at the Gulf of Suez in Egypt will be analysed. This area is chosen for its very high wind energy potential and the high concentration of migrating birds during spring and autumn. During...... the site selection and layout of a wind farm the balancing of interests and land use will be described....

  2. Wind farm planning at the Gulf of Suez

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, N E; Mortensen, N G; Hansen, J C [Risoe National Lab., Wind Energy Dept., Roskilde (Denmark); Clausager, I [Hedeselskabet A/S, Viborg (Denmark); Pagh Jensen, F [National Environmental Res., Copenhagen (Denmark); Georgy, L; Said, U S [New and Renewable Energy Authority, Egypt, (Egypt)

    2004-11-01

    The Wind Atlas for Egypt project is an element in a national effort to provide the best possible basis for planning of future environmentally sustainable development and utilization of wind energy resources and technology in Egypt. The present report compiles the data, information and recommendations available for planning of wind farm projects in the Gulf of Suez. (au)

  3. Ornithological studies of the Cold Northcott Wind Farm in the spring/summer 1994

    International Nuclear Information System (INIS)

    1996-01-01

    Results of ornithological studies carried out at Cold Northcott Wind Farm in North Cornwall during 1994 are presented. Flight patterns of species using the area were studied as were breeding patterns and bird mortality due to collisions with wind turbines. No significant effect on the spring and summer bird communities was observed. Long-term influences on the birds seem, rather, to stem from large scale population changes and local agricultural practice. Wind strength was shown to affect flight patterns in some species, but turbine operation seems unrelated. Death by collision with wind turbines is shown to be very rare. (UK)

  4. Wind Speed Estimation and Parametrization of Wake Models for Downregulated Offshore Wind Farms within the scope of PossPOW Project

    DEFF Research Database (Denmark)

    Göçmen Bozkurt, Tuhfe; Giebel, Gregor; Poulsen, Niels Kjølstad

    2014-01-01

    With increasing installed capacity, wind farms are requested to downregulate more frequently, especially in the offshore environment. Determination and verification of possible (or available) power of downregulated offshore wind farms are the aims of the PossPOW project (see PossPOW.dtu.dk). Two ...... period. The re-calibrated model has to be further parametrized to include dynamic effects such as wind direction variability and meandering also considering different averaging time scales before implemented in full scale wind farms....

  5. Operation and maintenance of offshore wind farms

    DEFF Research Database (Denmark)

    Petersen, Kristian R.; Madsen, Erik Skov; Bilberg, Arne

    The offshore wind industry is booming and larger, more efficient wind-turbines have constantly been introduced into the market. However, research within the field of the operation and maintenance (O&M) of offshore wind farms is limited as the field is still immature. In this paper, two current ma...... maintenance models - RCM and TPM - are discussed in this context. Furthermore, through a case study, the paper looks into Modularization and SSLP, as these concepts can be utilized to optimize maintenance. This is a new approach for the offshore wind industry....

  6. Infauna monitoring Horns Rev offshore wind farm. Annual state report 2004

    Energy Technology Data Exchange (ETDEWEB)

    Bech, M.; Frederiksen, R.; Pedersen, John; Leonhard, S.B.

    2005-04-15

    A total of 40 species were identified from the surveys in the Horns Rev area in September 2004 while 42 species were identified in 2003 and 47 species in September 2001. The decline in the number of species occurred both inside the wind farm and reference areas, which indicates that the decline could be a combination of changes in sediment characteristics and natural variation rather than an effect from the establishment of the wind farm. More species were not associated with the hard substrate at the turbine sites in 2004 compared to 2003, while in 2001, more species were associated with fine-grained sand. The median sediment grain size increased from 2001 to 2003 to 2004, which suggests that the velocity of the current increased, but modelling calculations on current speed predicted a 2% reduction in the wind farm area and up to a 15% reduction very close to the scour protection. These results agreed with the grain sizes found at the stations 5, 25 and 100 metres from the scour protection. At most stations, the medium grain size was 5 metres lower from the scour protection compared with the station 100 metres from the scour protection, which indicates that the velocity of the current was lower close to the scour protection. No significant impact on the infauna in the wind farm area was detectable concerning distance-related effects. Though general reductions in the population size of some of the character species in the surveyed areas might be related to changes in the sediment structure, the infauna community at Horns Rev showed no obvious sign of stress response as a consequence of possible impact from construction and operating activities. New species were observed in 2003 and 2004 and some of these might be a result of sediment characteristics, less predation or natural variation. The recording of other species might be a result of the introduction of hard bottom habitants in the wind farm area. The density of the most abundant bivalves and bristle worms was

  7. Infauna monitoring Horns Rev offshore wind farm. Annual status report 2004

    International Nuclear Information System (INIS)

    Bech, M.; Frederiksen, R.; Pedersen, John; Leonhard, S.B.

    2005-04-01

    A total of 40 species were identified from the surveys in the Horns Rev area in September 2004 while 42 species were identified in 2003 and 47 species in September 2001. The decline in the number of species occurred both inside the wind farm and reference areas, which indicates that the decline could be a combination of changes in sediment characteristics and natural variation rather than an effect from the establishment of the wind farm. More species were not associated with the hard substrate at the turbine sites in 2004 compared to 2003, while in 2001, more species were associated with fine-grained sand. The median sediment grain size increased from 2001 to 2003 to 2004, which suggests that the velocity of the current increased, but modelling calculations on current speed predicted a 2% reduction in the wind farm area and up to a 15% reduction very close to the scour protection. These results agreed with the grain sizes found at the stations 5, 25 and 100 metres from the scour protection. At most stations, the medium grain size was 5 metres lower from the scour protection compared with the station 100 metres from the scour protection, which indicates that the velocity of the current was lower close to the scour protection. No significant impact on the infauna in the wind farm area was detectable concerning distance-related effects. Though general reductions in the population size of some of the character species in the surveyed areas might be related to changes in the sediment structure, the infauna community at Horns Rev showed no obvious sign of stress response as a consequence of possible impact from construction and operating activities. New species were observed in 2003 and 2004 and some of these might be a result of sediment characteristics, less predation or natural variation. The recording of other species might be a result of the introduction of hard bottom habitants in the wind farm area. The density of the most abundant bivalves and bristle worms was

  8. Modeling wake effects in large wind farms in complex terrain: the problem, the methods and the issues

    DEFF Research Database (Denmark)

    Politis, E.S.; Prospathopoulos, J.; Cabezon, D.

    2012-01-01

    turbulence closures, are used. The wind turbines are modeled as momentum absorbers by means of their thrust coefficient through the actuator disk approach. Alternative methods for estimating the reference wind speed in the calculation of the thrust are tested. The work presented in this paper is part......Computational fluid dynamic (CFD) methods are used in this paper to predict the power production from entire wind farms in complex terrain and to shed some light into the wake flow patterns. Two full three-dimensional Navier–Stokes solvers for incompressible fluid flow, employing k - ε and k - ω...

  9. A Study of Wind Farm Stabilization Using DFIG or STATCOM Considering Grid Requirements

    Directory of Open Access Journals (Sweden)

    K. E Okedu

    2010-01-01

    Full Text Available Recently, the grid codes require taking into account the reactive power of the wind farm in order to contribute to the networkstability, thus operating the wind farm as active compensator devices. This paper presents a comparative study of stabilizinga wind farm using (Doubly Fed Induction Generators DFIGs or using a (Static Synchronous Compensator STATCOM duringwind speed change and grid fault. Simulation results show that the wind farm could be effectively stabilized with bothsystems, but at a reduced cost with the DFIGs system because it can provide reactive power through its frequency converterswithout an external reactive power compensation unit like the STATCOM system significant.

  10. Short-term ecological effects of an offshore wind farm in the Dutch coastal zone. A compilation

    Energy Technology Data Exchange (ETDEWEB)

    Lindeboom, H.J.; Brasseur, S.; Leopold, M.; Scheidat, M. [IMARES, PO Box 167, 1790 AD Den Burg (Netherlands); Kouwenhoven, H.J. [NoordzeeWind, 2e Havenstraat 5b, 1976 CE IJmuiden (Netherlands); Bergman, M.J.N.; Daan, R. [Royal NIOZ, PO Box 59, 1790 AB Den Burg (Netherlands); Bouma, S.; Fijn, R.C.; Dirksen, S.; Krijgsveld, K.L. [Bureau Waardenburg, PO Box 365, 4100 AJ Culemborg (Netherlands); De Haan, D.; Van Hal, R.; Hille Ris Lambers, R.; Ter Hofstede, R. [IMARES, PO Box 68, 1970 AB IJmuiden (Netherlands)

    2011-07-15

    The number of offshore wind farms is increasing rapidly, leading to questions about the environmental impact of such farms. In the Netherlands, an extensive monitoring programme is being executed at the first offshore wind farm (Offshore Windfarm Egmond aan Zee, OWEZ). This letter compiles the short-term (two years) results on a large number of faunal groups obtained so far. Impacts were expected from the new hard substratum, the moving rotor blades, possible underwater noise and the exclusion of fisheries. The results indicate no short-term effects on the benthos in the sandy area between the generators, while the new hard substratum of the monopiles and the scouring protection led to the establishment of new species and new fauna communities. Bivalve recruitment was not impacted by the OWEZ wind farm. Species composition of recruits in OWEZ and the surrounding reference areas is correlated with mud content of the sediment and water depth irrespective the presence of OWEZ. Recruit abundances in OWEZ were correlated with mud content, most likely to be attributed not to the presence of the farm but to the absence of fisheries. The fish community was highly dynamic both in time and space. So far, only minor effects upon fish assemblages especially near the monopiles have been observed. Some fish species, such as cod, seem to find shelter inside the farm. More porpoise clicks were recorded inside the farm than in the reference areas outside the farm. Several bird species seem to avoid the park while others are indifferent or are even attracted. The effects of the wind farm on a highly variable ecosystem are described. Overall, the OWEZ wind farm acts as a new type of habitat with a higher biodiversity of benthic organisms, a possibly increased use of the area by the benthos, fish, marine mammals and some bird species and a decreased use by several other bird species.

  11. Short-term ecological effects of an offshore wind farm in the Dutch coastal zone; a compilation

    Energy Technology Data Exchange (ETDEWEB)

    Lindeboom, H J; Brasseur, S; Leopold, M; Scheidat, M [IMARES, PO Box 167, 1790 AD Den Burg (Netherlands); Kouwenhoven, H J [NoordzeeWind, 2e Havenstraat 5b, 1976 CE IJmuiden (Netherlands); Bergman, M J N; Daan, R [Royal NIOZ, PO Box 59, 1790 AB Den Burg (Netherlands); Bouma, S; Fijn, R C; Dirksen, S; Krijgsveld, K L [Bureau Waardenburg, PO Box 365, 4100 AJ Culemborg (Netherlands); De Haan, D; Van Hal, R; Hille Ris Lambers, R; Ter Hofstede, R, E-mail: han.lindeboom@wur.nl [IMARES, PO Box 68, 1970 AB IJmuiden (Netherlands)

    2011-07-15

    The number of offshore wind farms is increasing rapidly, leading to questions about the environmental impact of such farms. In the Netherlands, an extensive monitoring programme is being executed at the first offshore wind farm (Offshore Windfarm Egmond aan Zee, OWEZ). This letter compiles the short-term (two years) results on a large number of faunal groups obtained so far. Impacts were expected from the new hard substratum, the moving rotor blades, possible underwater noise and the exclusion of fisheries. The results indicate no short-term effects on the benthos in the sandy area between the generators, while the new hard substratum of the monopiles and the scouring protection led to the establishment of new species and new fauna communities. Bivalve recruitment was not impacted by the OWEZ wind farm. Species composition of recruits in OWEZ and the surrounding reference areas is correlated with mud content of the sediment and water depth irrespective the presence of OWEZ. Recruit abundances in OWEZ were correlated with mud content, most likely to be attributed not to the presence of the farm but to the absence of fisheries. The fish community was highly dynamic both in time and space. So far, only minor effects upon fish assemblages especially near the monopiles have been observed. Some fish species, such as cod, seem to find shelter inside the farm. More porpoise clicks were recorded inside the farm than in the reference areas outside the farm. Several bird species seem to avoid the park while others are indifferent or are even attracted. The effects of the wind farm on a highly variable ecosystem are described. Overall, the OWEZ wind farm acts as a new type of habitat with a higher biodiversity of benthic organisms, a possibly increased use of the area by the benthos, fish, marine mammals and some bird species and a decreased use by several other bird species.

  12. Short-term ecological effects of an offshore wind farm in the Dutch coastal zone. A compilation

    International Nuclear Information System (INIS)

    Lindeboom, H.J.; Brasseur, S.; Leopold, M.; Scheidat, M.; Kouwenhoven, H.J.; Bergman, M.J.N.; Daan, R.; Bouma, S.; Fijn, R.C.; Dirksen, S.; Krijgsveld, K.L.; De Haan, D.; Van Hal, R.; Hille Ris Lambers, R.; Ter Hofstede, R.

    2011-01-01

    The number of offshore wind farms is increasing rapidly, leading to questions about the environmental impact of such farms. In the Netherlands, an extensive monitoring programme is being executed at the first offshore wind farm (Offshore Windfarm Egmond aan Zee, OWEZ). This letter compiles the short-term (two years) results on a large number of faunal groups obtained so far. Impacts were expected from the new hard substratum, the moving rotor blades, possible underwater noise and the exclusion of fisheries. The results indicate no short-term effects on the benthos in the sandy area between the generators, while the new hard substratum of the monopiles and the scouring protection led to the establishment of new species and new fauna communities. Bivalve recruitment was not impacted by the OWEZ wind farm. Species composition of recruits in OWEZ and the surrounding reference areas is correlated with mud content of the sediment and water depth irrespective the presence of OWEZ. Recruit abundances in OWEZ were correlated with mud content, most likely to be attributed not to the presence of the farm but to the absence of fisheries. The fish community was highly dynamic both in time and space. So far, only minor effects upon fish assemblages especially near the monopiles have been observed. Some fish species, such as cod, seem to find shelter inside the farm. More porpoise clicks were recorded inside the farm than in the reference areas outside the farm. Several bird species seem to avoid the park while others are indifferent or are even attracted. The effects of the wind farm on a highly variable ecosystem are described. Overall, the OWEZ wind farm acts as a new type of habitat with a higher biodiversity of benthic organisms, a possibly increased use of the area by the benthos, fish, marine mammals and some bird species and a decreased use by several other bird species.

  13. Advanced mesoscale forecasts of icing events for Gaspe wind farms

    International Nuclear Information System (INIS)

    Gayraud, A.; Benoit, R.; Camion, A.

    2009-01-01

    Atmospheric icing includes every event which causes ice accumulations of various shapes on different structures. In terms of its effects on wind farms, atmospheric icing can decrease the aerodynamic performance, cause structure overloading, and add vibrations leading to failure and breaking. This presentation discussed advanced mesoscale forecasts of icing events for Gaspe wind farms. The context of the study was discussed with particular reference to atmospheric icing; effects on wind farms; and forecast objectives. The presentation also described the models and results of the study. These included MC2, a compressible community model, as well as a Milbrandt and Yau condensation scheme. It was shown that the study has provided good estimates of the duration of events as well as reliable precipitation categories. tabs., figs.

  14. Societal acceptance of wind farms: Analysis of four common themes across Australian case studies

    International Nuclear Information System (INIS)

    Hall, N.; Ashworth, P.; Devine-Wright, P.

    2013-01-01

    Australia's renewable energy target (RET) seeks to provide 20 per cent of Australia's electricity generation from renewable energy sources by 2020. As wind power is relatively advanced, it was anticipated that wind power will contribute a major component of the early target. However, high levels of societal resistance to wind farms, combined with new regulatory policies, indicate the RET may not be dominated by wind power. This research involved an examination of seven case studies around wind farm deployment. Qualitative interviews were the primary data for the case studies and analysed using methods informed by grounded theory. Despite the diversity of stakeholder views, the qualitative analysis identified strong community support for wind farms but four common themes emerged that influence this societal acceptance of wind farms in Australia: trust, distributional justice, procedural justice and place attachment. Without addressing these factors through integration into policy development and engagement approaches, wind energy is unlikely to provide the early and majority of new renewable energy. Similar international experiences are incorporated in the discussion of the Australian wind industry's societal acceptance. - Highlights: ► Seven case studies of wind farms in Australia are described. ► Acceptance affects whether wind significantly contributes to the Aust. RE target. ► Four themes were identified regarding societal acceptance of Australian wind farms. ► Four themes are trust, distributional and procedural justice, and place attachment. ► International similarities to the Australian experience are provided

  15. The complete atlas of wind farms and projects in France

    International Nuclear Information System (INIS)

    Le Jannic, N.; Guillier, A.

    2012-01-01

    932 wind farms are in operation or in project at the end of the first semester of 2012 in France. Wind energy continues increasing, the total installed power reaches 7182 MW and about 738 MW have been installed during the last 12 months. This document lists all these wind farms and gives some information like the locality, the name of the operator, the power installed, the number of turbines, the name of the turbine manufacturer and the past or future date of commissioning. (A.C.)

  16. Assessing the impact on birds of prey of nine established wind farms in Thrace, NE Greece

    Energy Technology Data Exchange (ETDEWEB)

    Kret, Elzbieta; Carcamo, Beatriz; Zografou, Christina; Vasilakis, Dimitris

    2011-07-01

    Full text: In this study, we evaluate the impact on birds of prey of nine already established wind farms in Thrace, where a large scale wind farm development project of at least 930 MW is under development. Moreover, the area is acknowledged as of high ornithological interest, used for nesting, wintering and passage by rare territorial birds of prey, including the Near Threatened black vultures that use it for foraging. Finally, ca 50% of the wind farm development project area is covered by Natura 2000 sites. During the monitoring (2008-2010), carcass surveys were carried out in order to estimate mortality. In addition, avian space use surveys were carried out, in order to calculate indexes and to establish comparisons with a previous monitoring study run in 2004-05. In total, 14 birds of prey were found dead (one black vulture, four griffon vultures, one booted eagle, two short-toed eagles, one western marsh harrier, one Eurasian sparrow hawk, three common buzzards, one hawk species). The estimated mortality rate was 0.152 birds of prey (including vultures/turbine/year). Griffon vultures, black vultures and common buzzards comprised more than 50% of observations in the study area. Crossing densities between wind turbines were positively correlated with east exposition and the inclination of the slope, and the length of the wind turbines. gaps, while it was negatively correlated with north exposition. The use of the area was more intensive four years after the initial monitoring, but numbers of common buzzard observations drastically decreased. We suggest that during the planning phase of wind farms it is important to avoid steep slopes, east expositions and to take into account the distance between consecutive wind turbines. Our findings indicate that running a post-construction monitoring during only one year may not be enough to properly assess the impact of wind farms on birds of prey. (Author)

  17. Potential climatic impacts and reliability of very large-scale wind farms

    Directory of Open Access Journals (Sweden)

    C. Wang

    2010-02-01

    Full Text Available Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG emission technologies such as wind energy. The widespread availability of wind power has fueled substantial interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using wind turbines to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1 °C over land installations. In contrast, surface cooling exceeding 1 °C is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate wind turbines. Additional theory and new field observations will be required for their ultimate validation. Intermittency of wind power on daily, monthly and longer time scales as computed in these simulations and inferred from meteorological observations, poses a demand for one or more options to ensure

  18. Water-hydraulic power transmission for offshore wind farms

    NARCIS (Netherlands)

    Diepeveen, N.F.B.; Jarquin Laguna, A.; Kempenaar, A.S.

    2012-01-01

    The current state of the art of offshore wind turbine power transmission technology is expensive, heavy and maintenance intensive. The Delft Offshore Turbine project considers a radically new concept for power transmission in an offshore wind farm: using seawater as power transmission medium. For

  19. Wake Effects on Lifetime Distribution in DFIG-based Wind Farms