An original approach consisting on the combination of two wake patterns – a single wake model with a neutral boundary layer modification - is investigated in order to model large wind farm wake effect. Sensitivity studies of boundary layer parameters are carried out to optimize the velocity and power corrections whatever the type of wind farms and the wind directions. Two single wake models (Park and Fast EVM) were combined to a refined boundary layer model and validated against measurements and four standard wake models. This very promising model combination allows us to take into account the slowdown in large wind farms
This paper presents an analysis of CFD modelling, using a k-L turbulence model designed for forested areas. Meteodyn and Iberdrola Renovables have undertaken a systematic analysis of measurements data obtained in numerous sites, compared with Computation Fluid Dynamic approach. The analysis has consisted in highlighting the influence of several parameters on the shear defined as the vertical gradient of wind speed and the turbulence intensity at the wind turbine hub height. The influence is studied according to the forest description (density, height, shape of trees) and according to modelling parameters (Turbulent length scales, Dissipation parameter). Evaluation of the error ranges on wind shear and turbulence intensity is made according to the location of the wind turbines regarding the forest. www.meteodyn.com
Analytic Model of Wind Disturbance Torque on Servo Tracking AntennaIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
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International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This paper presents an analysis of CFD modelling, using a k-L turbulence model designed for forested areas. Meteodyn and Iberdrola Renovables have undertaken a systematic analysis of measurements data obtained in numerous sites, compared with Computation Fluid Dynamic approach. The analysis has consisted in highlighting the influence of several parameters on the shear defined as the vertical gradient of wind speed and the turbulence intensity at the wind turbine hub height. The influence is studied according to the forest description (density, height, shape of trees) and according to modelling parameters (Turbulent length scales, Dissipation parameter). Evaluation of the error ranges on wind shear and turbulence intensity is made according to the location of the wind turbines regarding the forest. www.meteodyn.com
Analytic Model of Wind Disturbance Torque on Servo Tracking AntennaIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This paper presents a study analysis of a complete wind energy conversion system, the system based on a doubly fed induction generator (DFIG); a vector control with stator flux orientation of the DFIG is also used to control independently the active and reactive powers. A comparative study have been performed between the conventional PI controller and fuzzy logic control to investigate its dynamic and static performances. This research work involves the study of a phase in advance, to provide effective assistance, to all those who have to make decisions regarding the planning and implementation of wind energy projects. The main objective is to model the wind chain and the use of two types of strategies for the control of this generator to ensure a good regulation we started with the modeling of the wind chain then the modeling of the DFIG and then the use of the two strategies for the regulation of the latter .The complete system is modeled and simulated in the MATLAB/ Simulink. The performance and robustness are analyzed and compared by Matlab / Simulink .Simulation results prove the excellent performance of fuzzy control unit as improving power quality and stability of wind turbine.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Performance Comparison of DFIG using Power Transfer Matrix and Direct Power...IAES-IJPEDS
This paper presents a direct power control and power transfer matrix model for a doubly-fed induction generator (DFIG) wind energy system (WES). Control of DFIG wind turbine system is traditionally based on either stator- flux-oriented or stator-voltage-oriented vector control. The performance of Direct Power Control (DPC) and Power transfer Matrix control for the same wind speed are studied. The Power transfer matrix Control gave better results. The validity and performance of the proposed modelling and control approaches are investigated using a study system consisting of a grid connected DFIG WES. The performance of DFIG with Power Transfer Matrix and Direct Power Control (DPC) techniques are obtained through simulation. The time domain simulation of the study system using MATLAB Simulink is carried out. The results obtained in the two cases are compared.
The following article presents the control of the power generated by the Doubly Fed Induction Generator, integrated into the wind system, whose rotor is linked to the power converters (Rotor Side Convert (RSC) and Grid Side Converter (GSC)) interfaced by the DC-BUS and connected to the grid via a filter (Rf, Lf) in order to obtain an optimal power to the grid and to ensure system stability. The objective of this study is to understand and to make the comparison between Sliding mode Control technique and the Flux Oriented Control in order to control the Doubly Fed Induction Generator powers exchanged with the grid, it also aims at maintaining the DC-BUS voltage constant and a unit power factor at the grid connection point.The results of simulation show the performance of the Sliding mode Control in terms of monitoring, and robustness with regard to the parametric variations, compared to the Flux Oriented Control. The performance of the systems was tested and compared with the use of MATLAB/Simulink software.
Improving the delivered power quality from WECS to the grid based on PMSG con...IJECEIAES
Renewable energy has become one of the most energy resources nowadays, especially, wind energy. It is important to implement more analysis and develop new control algorithms due to the rapid changes in the wind generators size and the power electronics development in wind energy applications. This paper proposes a grid-connected wind energy conversion system (WECS) control scheme using permanent magnet synchronous generator (PMSG). The model works to improve the delivered power quality and maximize its value. The system contained one controller on the grid side converter (GSC) and two simulation packages used to simulate this model, which were PSIM software package for simulating power circuit and power electronics converters, and MATLAB software package for simulating the controller on Simulink. It employed a meta-heuristic technique to fulfil this target effectively. Mine-blast algorithm (MBA) and harmony search optimization technique (HSO) were applied to the proposed method to get the best controller coefficient to ensure maximum power to the grid and minimize the overshoot and the steady state error for the different control signals. The comparison between the results of the MBA and the HSO showed that the MBA gave better results with the proposed system.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This paper proposes a feedback linearization control of doubly fed induction generator based wind energy systems for improving decoupled control of the active and reactive powers stator. In order to enhance dynamic performance of the controller studied, the adopted control is reinforced by a fuzzy logic controller. This approach is designed without any model of rotor flux estimation. The difficulty of measuring of rotor flux is overcome by using high gain observer. The stability of the nonlinear observer is proved by the Lyapunov theory. Numerical simulations using MATLAB-SIMULINK shown clearly the robustness of the proposed control, particularly to the disturbance rejection and parametric variations compared with the conventional method.
Economic Selection of Generators for a Wind Farmijeei-iaes
The selection suitable generator for wind turbines will be done based on technical criteria and priorities of the project. In this paper, a method for determining the type of wind turbine generator with an example is explained. In the paper, for a 10kW wind turbine, two generators have been proposed. The first case is a squirrel-cage asynchronous generator coupled to the turbine through the gearbox and directly connected to three phase output. Other PM generators that are directly coupled to the turbine and it is connected to the grid using the inverter. The results show that according to wind conditions, a 10kW permanent magnet generator is more advantageous in terms of energy production.
In this paper, we focus on the modeling and control of a wind power system based on a Permanent Magnet Synchronous Generator (PMSG). We proposed a technique of control strategies to have the maximum power from wind turbine (WT). This study deals with the problem of Maximum Power Point Tracking (MPPT) based on Takagi Sugeno fuzzy model. The stability analysis is achieved. The gains of the designed controller are calculated by solving Linear Matrix Inequality (LMI). Finally, simulation results are provided to demonstrate the validity and the effectiveness of the proposed method.
Novel Adaptive Controller for PMSG Driven Wind Turbine To Improve Power Syste...IJMERJOURNAL
ABSTRACT: This paper describes the behavior of a permanent magnet synchronous generator (PMSG) driven by wind turbine. The proposed conversion system is a good alternative due to its high efficiency and reliability. Electrolytic capacitors are not required in this type of converter and the voltage in the DC-link as well as the generated reactive power can be dynamically modified according to the wind velocity. The adaptive control strategy uses an adaptive PI which is self-tuned based on a linear approximation of the power system calculated at each sample time. Space vector technique for grid side inverter for transformer less integration of generator and a pulse-width modulated current source converter. A model reference is also projected in order to reduce the post-fault voltages. Simulation results prove the advantages of the proposed control. A MATLAB computer simulation study was undertaken and results on PWM-CSC are presented
Modeling of Wind Energy on Isolated AreaIJPEDS-IAES
In this paper, a model of the wind turbine (WT) with permanent magnet generator (PMSG) and its associated controllers is presented. The increase of wind power penetration in power systems has meant that conventional power plants are gradually being replaced by wind farms. In fact, today wind farms are required to actively participate in power system operation in the same way as conventional power plants. In fact, power system operators have revised the grid connection requirements for wind turbines and wind farms and now demand that these installations be able to carry out more or less the same control tasks as conventional power plants. For dynamic power system simulations, the PMSG wind turbine model includes an aerodynamic rotor model, a lumped mass representation of the drive train system and generator model. In this paper we propose a model with an implementation in MATLAB / Simulink, each of the system components off-grid small wind turbines.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...Yayah Zakaria
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind
speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
This paper presents a study analysis of a complete wind energy conversion system, the system based on a doubly fed induction generator (DFIG); a vector control with stator flux orientation of the DFIG is also used to control independently the active and reactive powers. A comparative study have been performed between the conventional PI controller and fuzzy logic control to investigate its dynamic and static performances. This research work involves the study of a phase in advance, to provide effective assistance, to all those who have to make decisions regarding the planning and implementation of wind energy projects. The main objective is to model the wind chain and the use of two types of strategies for the control of this generator to ensure a good regulation we started with the modeling of the wind chain then the modeling of the DFIG and then the use of the two strategies for the regulation of the latter .The complete system is modeled and simulated in the MATLAB/ Simulink. The performance and robustness are analyzed and compared by Matlab / Simulink .Simulation results prove the excellent performance of fuzzy control unit as improving power quality and stability of wind turbine.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Performance Comparison of DFIG using Power Transfer Matrix and Direct Power...IAES-IJPEDS
This paper presents a direct power control and power transfer matrix model for a doubly-fed induction generator (DFIG) wind energy system (WES). Control of DFIG wind turbine system is traditionally based on either stator- flux-oriented or stator-voltage-oriented vector control. The performance of Direct Power Control (DPC) and Power transfer Matrix control for the same wind speed are studied. The Power transfer matrix Control gave better results. The validity and performance of the proposed modelling and control approaches are investigated using a study system consisting of a grid connected DFIG WES. The performance of DFIG with Power Transfer Matrix and Direct Power Control (DPC) techniques are obtained through simulation. The time domain simulation of the study system using MATLAB Simulink is carried out. The results obtained in the two cases are compared.
The following article presents the control of the power generated by the Doubly Fed Induction Generator, integrated into the wind system, whose rotor is linked to the power converters (Rotor Side Convert (RSC) and Grid Side Converter (GSC)) interfaced by the DC-BUS and connected to the grid via a filter (Rf, Lf) in order to obtain an optimal power to the grid and to ensure system stability. The objective of this study is to understand and to make the comparison between Sliding mode Control technique and the Flux Oriented Control in order to control the Doubly Fed Induction Generator powers exchanged with the grid, it also aims at maintaining the DC-BUS voltage constant and a unit power factor at the grid connection point.The results of simulation show the performance of the Sliding mode Control in terms of monitoring, and robustness with regard to the parametric variations, compared to the Flux Oriented Control. The performance of the systems was tested and compared with the use of MATLAB/Simulink software.
Improving the delivered power quality from WECS to the grid based on PMSG con...IJECEIAES
Renewable energy has become one of the most energy resources nowadays, especially, wind energy. It is important to implement more analysis and develop new control algorithms due to the rapid changes in the wind generators size and the power electronics development in wind energy applications. This paper proposes a grid-connected wind energy conversion system (WECS) control scheme using permanent magnet synchronous generator (PMSG). The model works to improve the delivered power quality and maximize its value. The system contained one controller on the grid side converter (GSC) and two simulation packages used to simulate this model, which were PSIM software package for simulating power circuit and power electronics converters, and MATLAB software package for simulating the controller on Simulink. It employed a meta-heuristic technique to fulfil this target effectively. Mine-blast algorithm (MBA) and harmony search optimization technique (HSO) were applied to the proposed method to get the best controller coefficient to ensure maximum power to the grid and minimize the overshoot and the steady state error for the different control signals. The comparison between the results of the MBA and the HSO showed that the MBA gave better results with the proposed system.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This paper proposes a feedback linearization control of doubly fed induction generator based wind energy systems for improving decoupled control of the active and reactive powers stator. In order to enhance dynamic performance of the controller studied, the adopted control is reinforced by a fuzzy logic controller. This approach is designed without any model of rotor flux estimation. The difficulty of measuring of rotor flux is overcome by using high gain observer. The stability of the nonlinear observer is proved by the Lyapunov theory. Numerical simulations using MATLAB-SIMULINK shown clearly the robustness of the proposed control, particularly to the disturbance rejection and parametric variations compared with the conventional method.
Economic Selection of Generators for a Wind Farmijeei-iaes
The selection suitable generator for wind turbines will be done based on technical criteria and priorities of the project. In this paper, a method for determining the type of wind turbine generator with an example is explained. In the paper, for a 10kW wind turbine, two generators have been proposed. The first case is a squirrel-cage asynchronous generator coupled to the turbine through the gearbox and directly connected to three phase output. Other PM generators that are directly coupled to the turbine and it is connected to the grid using the inverter. The results show that according to wind conditions, a 10kW permanent magnet generator is more advantageous in terms of energy production.
In this paper, we focus on the modeling and control of a wind power system based on a Permanent Magnet Synchronous Generator (PMSG). We proposed a technique of control strategies to have the maximum power from wind turbine (WT). This study deals with the problem of Maximum Power Point Tracking (MPPT) based on Takagi Sugeno fuzzy model. The stability analysis is achieved. The gains of the designed controller are calculated by solving Linear Matrix Inequality (LMI). Finally, simulation results are provided to demonstrate the validity and the effectiveness of the proposed method.
Novel Adaptive Controller for PMSG Driven Wind Turbine To Improve Power Syste...IJMERJOURNAL
ABSTRACT: This paper describes the behavior of a permanent magnet synchronous generator (PMSG) driven by wind turbine. The proposed conversion system is a good alternative due to its high efficiency and reliability. Electrolytic capacitors are not required in this type of converter and the voltage in the DC-link as well as the generated reactive power can be dynamically modified according to the wind velocity. The adaptive control strategy uses an adaptive PI which is self-tuned based on a linear approximation of the power system calculated at each sample time. Space vector technique for grid side inverter for transformer less integration of generator and a pulse-width modulated current source converter. A model reference is also projected in order to reduce the post-fault voltages. Simulation results prove the advantages of the proposed control. A MATLAB computer simulation study was undertaken and results on PWM-CSC are presented
Modeling of Wind Energy on Isolated AreaIJPEDS-IAES
In this paper, a model of the wind turbine (WT) with permanent magnet generator (PMSG) and its associated controllers is presented. The increase of wind power penetration in power systems has meant that conventional power plants are gradually being replaced by wind farms. In fact, today wind farms are required to actively participate in power system operation in the same way as conventional power plants. In fact, power system operators have revised the grid connection requirements for wind turbines and wind farms and now demand that these installations be able to carry out more or less the same control tasks as conventional power plants. For dynamic power system simulations, the PMSG wind turbine model includes an aerodynamic rotor model, a lumped mass representation of the drive train system and generator model. In this paper we propose a model with an implementation in MATLAB / Simulink, each of the system components off-grid small wind turbines.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...Yayah Zakaria
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind
speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...IJECEIAES
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
Wind-Driven SEIG Systems: A Comparison StudyCSCJournals
Wind energy is one of the fastest growing renewable energies in the world. This is because it has a much lower environmental impact than conventional energy. In addition, it is one of the lowest-priced renewable energy technologies.
Due to wind speed variation, induction generators are the best choice for such applications. However, they have poor voltage and frequency regulation against wind speed or load variations.
For its operation, the induction generator needs a reasonable amount of reactive power. In stand-alone applications, the reactive power could be supplied to the induction generator by a bank of capacitors as implemented here.
In this paper, simulation of wind turbine driven self excited induction generator (SEIG) has been carried out. Three methods of voltage and frequency regulation have been presented, simulated and analyzed.
The aim of this paper is to compare the three methods from many aspects highlighting the advantages and disadvantages of each one.
Quantification of operating reserves with high penetration of wind power cons...IJECEIAES
The high integration of wind energy in power systems requires operating reserves to ensure the reliability and security in the operation. The intermittency and volatility in wind power sets a challenge for day-ahead dispatching in order to schedule generation resources. Therefore, the quantification of operating reserves is addressed in this paper using extreme values through Monte-Carlo simulations. The uncertainty in wind power forecasting is captured by a generalized extreme value distribution to generate scenarios. The day-ahead dispatching model is formulated as a mixed-integer linear quadratic problem including ramping constraints. This approach is tested in the IEEE-118 bus test system including integration of wind power in the system. The results represent the range of values for operating reserves in day-ahead dispatching.
Performance of a Wind System: Case Study of Sidi Daoud SiteIJERA Editor
This paper describes recent developments of systems for the conversion of wind energy. It presents a modeling and simulation of wind energy conversion system at the site of Sidi Daoud using the experimental results obtained by the services of the company STEG and Madee. We determined the performance of machines based on site properties and dimensional characteristics of the device.
Dynamic Modeling of Autonomous Wind–diesel system with Fixed-speed Wind TurbineIJAPEJOURNAL
Wind turbines have often connected to small power systems, operating in parallel to diesel generators, as is typically the case in autonomous wind–diesel installations or small island systems with high wind potential. Hence, the modeling and analysis of the dynamic behavior of wind–diesel power systems in presence of wind power will be important. In this paper, the system under study is modeled by a set of dynamic and algebraic equations (DAE). Dynamic behavior of a wind-diesel system is investigated by the proposed dynamic model. Wind-diesel system consists of wind turbines that are connected to synchronous diesel generator via short transmission line with local load. Dynamic stability of autonomous wind–diesel systems are discussed with emphasis on the eigenvalue analysis and the effective parameters on system stability. In this regards, saddle node bifurcation and hopf bifurcation are also investigated.
Feasibility Study of a Grid Connected Hybrid Wind/PV SystemIJAPEJOURNAL
This paper investigates the feasibility of a grid connected, large-scale hybrid wind/PV system. From data available an area called RasElnaqab in Jordan is chosen because it enjoys both high average wind speed of 6.13 m/s and high average solar radiation of 5.9KWhr/m2 /day. MATLAB and HOMER software’s are used for sizing and economical analysis respectively. Results show that76124 SUNTECH PV panels and 38 GW87-1.5MW wind turbines are the optimal choice. The net present cost (NPC) is 130,115,936$, the cost of energy (COE) is 0.049$/KWhr with a renewable fraction of 74.1%.A stepby-step process to determine the optimal sizing of Hybrid Wind/PV system is presented and it can be applied anywhere.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Eternal Sun Group - Bifacial measurements, towards a new norm!Marcello Passaro
ITRPV and customers feedback show that there is a shift towards bifacial modules, however a concern on how to correctly test bifacial modules. Eternal Sun Group has together with research and development institutes like ECN looked at the complications and implications hereof.
Validation of wind resource assessment process based on CFD Jean-Claude Meteodyn
Wind resource assessment requires nowadays more efficient tools to provide an accurate evaluation of production in order to reduce costs.As onshore wind farms are built in more complex terrains, it is necessary to find a new method to provide a fine evaluation of energy which reduces the error during the data extrapolation process. This explains why CFD models have become a standard for WRA in specific conditions.This presentation is focused on the wind speed and energy yield prediction carried out for a 29MW wind farm project. The accuracy of the wind modeling is investigated by the cross validation between the different met masts around the site. The net energy prediction P50 is compared against real wind farm performance data during a blind test organized by EWEA in 2013. More than 50 companies have been involved in order to compare methods results.
Heuristic Optimization Technique for CHP-Wind Power Dispatchidescitation
This paper applies Differential Evolution (DE) for
solving combined heat and power dispatch (CHP) problem with
wind turbines. The CHP economic dispatch problem consist
of two sub problems, namely, heat dispatch and power dispatch.
The optimal dispatch utilization of multiple CHP units and
wind turbines is a complicated problem due to the complex
constraints such as feasible operating regions created by
mutual dependence of heat and power. The uncertainty of
wind speed and wind power is modeled using the Weibull
probability distribution. Economic dispatch is carried out for
cost optimization with varying wind power. The proposed
method is able to handle all complex constraints very
effectively without any violations. The developed optimization
model is tested and validated on a study system from literature.
Wind resource assessment on a complex terrain: Andhra Lake project - IndiaJean-Claude Meteodyn
This paper presents an evaluation of the CFD software’s performance based on cross-comparisons between met masts results. It gives an approach on uncertainty values in non standard conditions: very sharp reliefs, very large domain and large distances between the masts.
In fact, the Andhra Lake wind farm is located on a very sharp terrain, where 117 out of 142 turbines fail to conform to the “complex” terrain characterization according to the 61400-1 Ed3 standard. The reference meteorological data come from a long measurement campaign with five met masts with a maximal height of 50 m/57 m. A complete assessment study including the estimation of the Long Term Annual Energy Output (LTAEO), load conditions and turbine suitability has been performed by means of the CFD software meteodyn WT.
Energy Yield Assessment and Site Suitability using OpenFOAM - Crasto, Castell...Giorgio Crasto
A procedure has been implemented in order to assess the Annual Energy Production (AEP) of a wind farm. The pieces of software used for the porpoise are Octave, Meshlab and OpenFOAM. Two test cases are presented, in the second one also a first comparison with real production data.
This paper by Meteodyn and ZephIR Lidar, presented at the Wind Europe summit 2016, explains how to use CFD to post process Lidar wind speed data in complex sites. Indeed, there is a known strong inhomogeneity of wind in areas of complex flow which may cause some discrepancies between volume-based Lidar measurements and point-based measurements from standard anemometers. The only reliable solution to reduce uncertainties and get the most accurate energy yield predictions is to use CFD modelling...
Modelling wind flow in forested area - study by Meteodyn and Iberdrola Renewa...Jean-Claude Meteodyn
Meteodyn and Iberdrola Renovables have undertaken a systematic analysis of measurements data obtained in numerous sites, compared with Computation Fluid Dynamic approach. The analysis has consisted in highlighting the influence of several parameters on the shear defined as the vertical gradient of wind speed and the turbulence intensity at the wind turbine hub height. The influence is studied according to the forest description (density, height, shape of trees) and according to modelling parameters (Turbulent length scales, Dissipation parameter). Evaluation of the error ranges on wind shear and turbulence intensity is made according to the location of the wind turbines regarding the forest....
This paper presents a systematic analysis of wind measurements over several forested areas, in order to evaluate the uncertainties and to define new parameters to take into account the variety of forest configurations, including thermal effects. As a result, a new model for k-L RANS CFD models has been proposed, tested and validated. The main discrepancies are found in the near wake where CFD underestimates the shear effect of the forest.
Thermal stratification in cfd modelling for wind resource assessmentJean-Claude Meteodyn
Up to know CFD computations in wind resource assessment mainly focused on wind statistics treatment, and then considered average thermal structure of the atmosphere. With an increasing demand for a more accurate description of these statistics, including time series, there is a need for considering more specific situations, and particularly stable thermal stratifications (ref 1). We present here a new turbulence model allowing to consider the strongly stable cases in CFD computations.
Use of mesoscale modeling to increase the reliability of wind resource assess...Jean-Claude Meteodyn
During wind farm design phase, the wind direction distribution is a crucial information for wind turbine layout optimization. However, in complex terrains, the wind rose at hub height of the wind turbines can be quite different from met mast measurement.The study shows that in complex terrains, the use of mesoscale modeling provides a complement to met mast measurement. It allows to better determine the turbine-specific wind rose and to reduce the uncertainty in wind resource assessment. The coupling of mesoscale and CFD model allows to produce high resolution wind map, by taking into account both mesoscale and microscale terrain effects.
One-day ahead Power Forecasting is more and more required on the energy markets, and its accuracy is more and more crucial since it affects the net income of operators. 1. Weather Numerical Prediction, including a meso scale downscaling, provides a global prediction. A RANS CFD-tools is used for the micro-scale downscaling, providing a precise wind forecast at each wing generator hub. 2. To improve the reliability of this forecast, especially in the short term range, the use of "fresh" SCADA data is performed. Attention is focused on the Active Power, but other signals such as temperature and local wind characteristics can be taken into account. 3. In order to erase systematic errors and bias from the downscaled NWP based forecast (1.), as well as to mix it with the persistent model (2.), an Artificial Neural Network is trained using long term history. This paper explains first the method used and the choices made, especially concerning the Machine Learning parameters. A second part presents some results on some real cases, with different time horizons.
HYPERWIND Project: global and systemic monitoring of offshore renewable power...Jean-Claude Meteodyn
HyperWind is a project to develop a comprehensive
monitoring system for Offshore and On Shore wind
turbines. Meteodyn is working to develop a methodology for modeling system behavior. http://meteodyn.com
New features presentation: meteodyn WT 4.8 software - Wind EnergyJean-Claude Meteodyn
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At present, with the development of wind power project in China, there are more and more projects located at the complex terrain and complex environment. At the same time, since the large planned area of project, the complex mountain area, and limited number of met mast, even without met mast, in order to the reliable development of the wind power project, it is important that how to do the wind resource assessment without actual measurement wind data and other conditions such as less reliable wind data, and the met mast was not considered representative. This paper will use the atmospheric model to do mesoscale simulation calculation of wind resources, and then combine with CFD technology to downscaling computation to get high resolution wind power assessment result. Finally, in order to confirm the validity of this application in the actual project, the comparison between calculation values and measurement values is carried out. The verification result through the actual data of different met mast shows that the wind resource assessment method which combines the CFD and mesoscale technologies is reliable. The main contribution of the article is to provide the reference model and approach for regional planning and large scale wind resource assessment when there isn’t enough adequate and effective wind data.
Optimal combinaison of CFD modeling and statistical learning for short-term w...Jean-Claude Meteodyn
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Wind flow simulations on forested zone have been performed with Computational Fluid Dynamics (CFD) software meteodyn WT, which allows introducing a custom forest canopy model. The influence of parameter changes on results is investigated. The calibration of model parameters is done by minimizing the error between the CFD results and the vertical wind profiles given by the European standard Eurocode 1 (EC1), applied to standard terrains for high roughness cases. The calibrated model shows good coherence with EC1. To check the validity of the forest modeling in the real case, CFD simulation has been performed on a site with heterogeneous forest covering. The computed wind characteristics are then compared to met mast measurement. The comparison shows good agreement on wind shear and turbulence intensity between the simulation results and the measured data.
Correction tool for Lidar in complex terrain based on CFD outputsJean-Claude Meteodyn
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Lidars like the WINDCUBE by Leosphere or the ZEPHIR by Natural Power have a proven accuracy on flat terrains, while in complex terrain, the loss of flow homogeneity can create a sensor bias during the transformation of measured radial wind speed to horizontal wind speed (in some cases up to 10%).Therefore, a tool is needed to enable the correction of Lidar data in complex terrain.
It has been shown that CFD’s (computational fluid dynamics) models are recommended instead of linear models in complex terrain in order to get accurate characteristics of the wind flow. Thus, using the Meteodyn WT CFD results such as wind speed up factor and inflow angle, a method to correct two kinds of Lidars data is presented and validated. These data are then directly used for wind resource assessment. The studies on semi-complex terrain underline the quality of the correction which allows the user to obtain climatological files with a small uncertainty which reduces the uncertainties in the assessment of the annual energy production.
New features in the version 4.5 of the CFD meteodyn WT dedicated to wind reso...Jean-Claude Meteodyn
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GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...
Wake model for wind farm - Meteodyn
1. Investigation and validation of wake model combinations for large wind
farm modelling in neutral boundary layers
Eric TROMEUR(1)
, Sophie PUYGRENIER(1)
,Stéphane SANQUER(1)
(1)
Meteodyn France, 14bd Winston Churchill, 44100, Nantes, France
ABSTRACT
An original approach consisting on the combination of two wake patterns – a single wake model with a neutral
boundary layer modification - is investigated in order to model large wind farm wake effect. Sensitivity studies
of boundary layer parameters are carried out to optimize the velocity and power corrections whatever the type of
wind farms and the wind directions. Two single wake models (Park and Fast EVM) were combined to a refined
boundary layer model and validated against measurements and four standard wake models. This very promising
model combination allows us to take into account the slowdown in large wind farms.
1 Introduction
When air under neutral conditions flows from one surface through a wind turbine with a
different roughness, the air is slowed [1][2], an internal boundary layer growing downwind
from the roughness change [3][4][5]. The region in the flow behind the turbine is called the
wake of a wind turbine. Its effects are seen as wake effects.
It is thus important to evaluate and model these effects and boundary layer changes to
estimate the amount of power remaining downstream of the turbine.
Wind resource softwares like WindFarmer [6], Wakefarm [7], WaSP [8][9], NTUA [10] or
Meteodyn WT [11] were evaluated for small wind farms [12] or single wakes [13]. However,
it has become apparent that standard single wake models as Park [14][15] and Fast EVM [16]
models tend to underestimate wake losses in large wind farms as offshore arrays [17].
In this paper, an original approach consisting on the combination of two wake patterns – a
single wake model with a neutral boundary layer modification - is investigated and validated
against measurements and four standard wake models as in [18] in order to model large wind
farm wake effect and compute velocity deficit.
2 Measurements
Wind turbine power production data from two large offshore wind farms, Horns Rev and
Nysted, are used to validate our large wind farm model results as in [18]. The normalized
power (with respect to the power of the first wind farm column, see figure 1) at each turbine
is calculated for seven wind direction sectors centered on an exact wind farm row (ER) ( 270°
+/- 2.5° at Horns Rev and 278° +/- 2.5° at Nysted), and for mean wind directions of +5°,
+10°, and +15° and -5°, -10°, and -15° from ER. Flow down at ER thus represents the likely
maximum wake effect, while the wind directions that are slightly offset from ER assist in
assessing the wake width.
In both cases, wake effects is evaluated for a free-stream velocity mainly coming from the
west (not shown) and equal to 8 m.s-1
as in [18].
2. Figure 1: Horns rev wind farm layout [18].
3 Large wind farm model: parametrization and activation
Single wake models don’t consider the change of the atmospheric boundary layer by the
additional roughness associated with wind turbines. An original approach consists on
calculating the velocity deficit in each point of the wind farm by combining a wake effect
from a single wind turbine with the boundary layer modification.
Two single wake models (Park and Fast EVM) used in Meteodyn WT software [11] and a
large wind farm model taking into account inner boundary layer (IBL) modification are
combined and named WT Park+IBL and WT Fast EVM+IBL.
The boundary layer profile is then expressed as a function of the equivalent roughness z'0 and
the wind position relative to the upstream turbine.
Three steps and sensitivity studies are necessary to optimize and compute the velocity deficit
via combined wake models:
1. Equivalent roughness z'0 computation
2. Boundary layer profile estimation
3. Large wind farm model activation
3.1 Roughness z'0 influence
The equivalent roughness z'0 is calculated with the method of Frandsen [19][20] for each
wind direction and wind speed at each turbine. It depends on the spacing between two rows
of wind turbines along the wind direction Sd and the crosswind direction Sc. Sc has a huge
influence on the roughness (example on Figure 2 for the wind turbine WT74 at the Horns
Rev with Sd = 7). It impacts directly the normalized power with respect to the wind turbine
WT04, going down to 10% if Sc = 3 (see Table 1).
An algorithm has been developed to optimize Sc and Sd whatever the type of wind farms and
the wind directions. Figure 3 presents an example of Sc and Sd evolutions at Horns Rev for
ER incidence (other incidences not shown here).
3. Figure 2: Frandsen roughness function of wind speed and Sc with Sd=7 at ER incidence and wind turbine WT74
at Horns Rev
Table 1: Normalized power evolution function of z'0, Sc and Sd
The number of upstream wind turbines for a specific position is increasing for a wind turbine
going far away from the first column of the array. Sc and Sd are homogeneous over the all
wind farm considering at least one wind turbine is detected upstream. Sc and Sd has been
found equal to 7 for both wind farms in Denmark.
3.2 Inner boundary layer influence
The velocity deficit coefficient correction is the ratio between the wind speed in the IBL and
the wind speed taken at the same height before the roughness change. However, an offset
Hstart (function of the fetch and z’0.) from which the boundary layer starts and the IBL height
hibl influence it. Sensitivity studies of Hstart and hibl are then carried out at Horns Rev with the
two combined wake models in order to optimize wind speed and power corrections:
As shown in Table 2, the more Hstart is low, the more velocity and power deficits are
low. On the contray to [6] proposing Hstart = 2/3 hhub (with hhub the hub height), the
optimum Hstart is equal to zero, meaning the inner boundary layer influence starts from
the ground.
According to [21], 0.05h ≤ hibl ≤ 0.09h, where h is the boundary layer height.
Comparisons between both combined models and observations in Figure 4 show a
better agreement for hibl=0.05h (case B/) against 9% of h in [6]. The same is observed
for all other directions, except for ER-15° and ER-10° (not shown).
4. Figure 3: Evolution of Sc and Sd at ER incidence at Horns Rev
Table 2: Evolution of wind speed and power correction function of Hstart for the wind turbine WT74 at incidence
ER at Horns Rev (WT Park+IBL model). Drotor is the rotor diameter.
5. Figure 4: Normalized power at ER +15° at Horns Rev for ibl = 0.09 (A/) and 0.05 (B/).
All these optimized parameters are considered by default in the next validation section 4.
3.3 Large wind farm model activation
A geometric measure of turbine density is used to activate the large wind farm model.
Considering the turbine density for 5° sectors, the large wind farm correction to ambient wind
speed is applied if there is at least one turbine in the selected sector. Moreover, this model is
always activated from the fourth wind farm column.
Finally, the velocity deficit is computed as the velocity deficit minimum taken between the
large wind farm model and the single wake Park or Fast EV models.
6. Figure 5: Mean normalized power from Horns Rev (top), Nysted (down) and model simulations for the second
(left) and the eighth (right) columns of wind turbines.
4 Model comparisons with offshore wind farm data
A model intercomparison is performed at the two offshore wind farms for four different wake
models as in [18] and the two combined models.
4.1 Wake width
As for other models, WT Park and Fast EVM models+IBL capture well the wake width at the
second column of wind turbines (Figure 5) and show greater agreement with the observed
wake depth than WaSP though both overestimate (respectively underestimate) the magnitude
of the wake width at Horns Rev (Nysted).
For the entire wind farm (column 8), normalized powers of both combined models fit better
with observations than other models even if they tend to overestimate (underestimate) the
power for sectors less (greater) than ER.
In general, the root-mean-square error (RMSE) of normalized power shown in Table 3
indicates that WT Park+IBL and WT Fast EVM+IBL models perform better (i.e., exibit lower
RMSE) for direct flow down the row (i.e, ER) than for oblique angles.
4.2 Power deficit by downwind distance
In Figures 6 and 7, both combined models appear to capture the shape of power deficit as a
function of distance into both wind farms. In general, WT Fast EMV+IBL model has a very
good agreement with Windfarm and WindFarmer models, being even better at an incident
wind directions of 255°, 260°, 275°, 285° for Horns Rev and 263°, 268°, 273°, 283° for
Nysted.
7. Table 3: RMSE of normalized power from the models vs observations at Horns Rev (top) and Nysted (down).
5 Conclusion
Investigation for large wind farm modelling under neutral conditions have been carried out by
combination of two single wake models (Park and Fast EVM) with a refined version of
boundary layer models based on [6] and [21].
Sensitivity studies of IBL parameters (Sc , Sd, Hstart and hibl) allow us to design optimum
combination whatever the type of wind farms and wind directions.
The large wind farm models are then validated against measurements and four standard wake
models, suggesting combined wake models well represent the losses in those wind farms.
In the future, a linear combination of single wake models with the boundary layer
modification will be investigated to compute velocity and power deficits.
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