Wind Farm Design Research Articles

Key Issues on the Design of an Offshore Wind Farm Layout and Its Equivalent Model

Offshore wind farms will have larger capacities in the future than they do today. Thus, the costs that are associated with the installation of wind turbines and the connection of power grids will be much higher, thus the location of wind turbines and the design of internal cable connections will be even more important. A large wind farm comprises of hundreds of wind turbines. Modeling each using a complex model leads to long simulation times—especially in transient response analyses. Therefore, in the future, simulations of power systems with a high wind power penetration must apply the equivalent wind-farm model to reduce the burden of calculation. This investigation examines significant issues around the optimal design of a modern offshore wind farm layout and its equivalent model. According to a review of the literature, the wake effect and its modeling, layout optimization technologies, cable connection design, and wind farm reliability, are significant issues in offshore wind farm design. This investigation will summarize these important issues and present a list of factors that strongly influence the design of an offshore wind farm.

Realistic wind farm design layout optimization with different wind turbines types

Seeking for an appropriate design of wind farm (WF) layout constitutes a complex task in a wind energy project. An optimization approach is seriously needed to deal with this complexity, especially with current trend of large WFs area with important number of wind turbines (WTs). The present paper investigates optimization study of realistic offshore WF design layout (horns-rev1). The main objective of the current study is to design WF area that maximizes the extraction of wind power with low cost. In the first step, an optimization model using genetic algorithm with continuous layout representation is developed to look for the optimal design as a function of WTs placement. The effectiveness of such a methodology is validated and compared with the reference and irregular layout of hors-rev1 offshore WF. With the aim to analyze the impact of WTs types on WF objectives, four commercial WTs are considered in the second step. The results showed that designing WF with big WTs gives best design layout. In addition, it demonstrated that selecting WTs based uniquely on rotor diameter size is not always a good idea. It should includes as well the number of WTs that influence significantly the power production and WF cost.

Vindby—A Serious Offshore Wind Farm Design Game

To maintain the increasing interest and development in offshore wind energy, novel training tools for engineers and researchers are needed. Concurrently, educational outreach activities are in demand to inform the public about the importance of offshore wind energy. In this paper, the development of a serious game about the design and management of offshore wind farms is presented to address such demands. Such a serious game may enable a new audience to explore the field of offshore wind as well as provide researchers entering the field a better understanding of the intricacies of the industry. This requires a simulation that is realistic but also effective in teaching information and engaging outreach. Ultimately, increased public support and expanded training tools are desired to improve decision-making and to provide opportunities to test and integrate innovative solutions. The work presented here includes the game design and implementation of a prototype game. The game design involves building a game framework and developing a simplified simulation. This simulation addresses weather prediction, offshore wind farm design, operation and maintenance, energy demand, climate change, and finance. Playtesting of the prototype demonstrated immersion and informed decision-making of the players and surveys revealed that knowledge had increased while playing the game. Recommendations for future versions of the game are listed.

Development of a Computational System to Improve Wind Farm Layout, Part II: Wind Turbine Wakes Interaction

The second part of this work describes a wind turbine Computational Fluid Dynamics (CFD) simulation capable of modeling wake effects. The work is intended to establish a computational framework from which to investigate wind farm layout. Following the first part of this work that described the near wake flow field, the physical domain of the validated model in the near wake was adapted and extended to include the far wake. Additionally, the numerical approach implemented allowed to efficiently model the effects of the wake interaction between rows in a wind farm with reduced computational costs. The influence of some wind farm design parameters on the wake development was assessed: Tip Speed Ratio (TSR), free-stream velocity, and pitch angle. The results showed that the velocity and turbulence intensity profiles in the far wake are dependent on the TSR. The wake profile did not present significant sensitivity to the pitch angle for values kept close to the designed condition. The capability of the proposed CFD model showed to be consistent when compared with field data and kinematical models results, presenting similar ranges of wake deficit. In conclusion, the computational models proposed in this work can be used to improve wind farm layout considering wake effects.

Comparative Study of Wind Turbine Placement Methods for Flat Wind Farm Layout Optimization with Irregular Boundary

For the exploitation of wind energy, planning/designing a wind farm plays a crucial role in the development of wind farm project, which must be implemented at an early stage, and has a vast influence on the stages of operation and control for wind farm development. As a step of the wind farm planning/designing, optimizing the wind turbine placements is an effective tool in increasing the power production of a wind farm leading to an increased financial return. In this paper, the optimization of an offshore wind farm with an irregular boundary is carried out to investigate the effectiveness of grid and coordinate wind farm design methods. In the study of the grid method, the effect of grid density on the layout optimization results is explored with 20 × 30 and 40 × 60 grid cells, and the means of coping with the irregular wind farm boundary using different wind farm design methods are developed in this paper. The results show that, depending on the number of installed wind turbines, a power output increase from 1% to 1.5% is achieved by increasing the grid density from 20 × 30 to 40 × 60. However, the computational time is more than doubled, rising from 23 h to 47 h with 40 wind turbines being optimized from the coarse grid cells to the densified grid cells. In comparison, the coordinate method is the best option for achieving the largest power increase of 1.5% to 2% (relative to the coarse 20 × 30 grid method), while the least computational time (21 h with 40 wind turbines optimized) is spent.

Layout optimization of a wind farm using geometric pattern-based approach

Abstract Wind farm design deals with the optimal placement of turbines in a wind farm to maximizes the expected power output and increase the overall efficiency of a wind farm. In the present study, a novel procedure known as a geometrical pattern inspired placement methodology is introduced to position wind turbines to maximize the total power output of a wind farm located at the Kutch district at the west cost of the Gujarat province of India. The enhanced passing vehicle search (PVSe) algorithm is applied to rectangular wind farm considering the multi-directional variable wind velocity. The numerical results are compared with the existing placement of turbines at a wind farm. The numerical results indicate that the power output obtained by the geometrical pattern based approach is improved by 4.29 percentages compared to the existing wind farm layout at Kutch district.

Stability Assessment on Doubly Fed Induction Generator (DFIG) Wind Turbine Micro Grid Power System

As of late, expanding interest of renewable energy and consumption of non-renewable energy source have prompted developing advancement of renewable energy technology, for example, wind energy. Wind energy has turned out to be one of the reliable sources of renewable energy, which requests extra transmission capacity and better methods for sustaining system reliability. As of now, doubly fed induction generator wind turbine is the most well-known wind turbine. This paper focuses on DFIG wind farm design using MATLAB/SIMULINK and also investigates the issues of the system stability of the DFIG wind turbine micro grid power system. This analysis includes the changes of voltage, current, real power and reactive power based on various conditions of the power system.

A bimodal Weibull distribution - capacity factor for different heights at sulur

Due to developing environmental concern use of renewable energy source is very essential. The great demand for the energy supply coupled with inadequate energy sources creates an emergency to find a new solution for the energy shortage. The appropriate wind energy distribution is the fundamental requirement for the assessment of wind energy potential available at the particular site essential for the design of wind farms. Hence the proper specification of the wind speed distribution plays a vital role. In this paper the Bimodal Weibull distribution is used to estimate the Capacity factor at the proposed site. The shape and scale parameters estimated using Maximum likelihood method is used as the initial value for extrapolation. Application of this model will give an accurate result overwhelming the concept of overestimation or underestimation of Capacity factor.

North Sea as geo database

A national database of detailed 2D data and 1D ground investigation data is being developed for the Dutch sector of the North Sea. The 2D data mostly comprise interpreted results of high-resolution seismic reflection surveys. The ground investigation data typically comprise cone penetration test (CPT) results, S-wave velocity derived from seismic downhole tests, soil sample descriptions, soil sample classifications and results of geotechnical laboratory tests. The availability of public-domain geodata is rapidly increasing, primarily because of a licensing approach in which the Dutch government provides geotechnical and geological data to tenderers for design and operation of wind farms. The increasing availability of geodata provides new interests and opportunities for the apportioning, development and maintenance of offshore and coastal facilities. This paper describes the contents of the geo database. In addition, it discusses opportunities for testing and validation of new methods for site investigation, as well as integration of geophysical data, CPT results and sample data for state-of-the-art mapping and ground modelling purposes.

A Practical Short-Circuit Current Calculation Method for DFIG-Based Wind Farm Considering Voltage Distribution

This paper presents a calculation method of short-circuit current (SCC) for doubly fed induction generator (DFIG)-based wind farm considering the voltage distribution characteristics. When a short-circuit fault occurs in a wind farm, a large SCC will be contributed by the dozens or even hundreds of DFIGs in the wind farm. And the security and stability of the wind farm will be affected by the SCC. The SCC characteristics of the DFIG are closely related to its post-fault terminal voltage (PFTV). Therefore, a practical calculation model of SCC in single DFIG is proposed in this paper, based on the electromagnetic transient analysis. And according to a correction method of the topological matrix for a post-fault wind farm proposed in this paper, the relationship model between voltages and currents under short-circuit faults is established. Then, the PFTVs and SCCs of the DFIGs in the wind farm can be obtained by solving the model equation. Finally, the proposed method is validated through MATLAB/Simulink-based simulation results, and a comparison with the national standard calculation method is analyzed. The results show that this method has better accuracy, which provides a more accurate basis for the electrical safety design of wind farms.

ANALYSIS OF WAVE CHARACTERISTICS FOR DESIGN AND CONSTRUCTION OF OFFSHORE WIND POWER PLANT

The potential of offshore wind power in Japan is high, because Japan is surrounded by the sea on all sides. For this reason, proving research and planning of wind farms have been conducted in various locations. However the introduction is delayed compared with Europe due to severe natural conditions such as typhoons and swells unique to Japan. Offshore Choshi is one of the suitable sites for wind power generation on the Pacific side, but there is no data about characteristics of high waves required for setting the design conditions and characteristics of low waves required for the construction onsite. Therefore in this research, we aim to establish the design and construction of offshore wind farm adapted to Japan, using wave data obtained by proving research offshore Choshi, to investigate the wave characteristics for wind farm design and construction.

Optimal Irregular Wind Farm Design for Continuous Placement of Wind Turbines with a Two-Dimensional Jensen-Gaussian Wake Model

Optimal design of wind turbine placement in a wind farm is one of the most effective tools to reduce wake power losses by alleviating the wake effect in the wind farm. In comparison to the discrete grid-based wind farm design method, the continuous coordinate method has the property of continuously varying the placement of wind turbines, and hence, is far more capable of obtaining the global optimum solutions. In this paper, the coordinate method was applied to optimize the layout of a real offshore wind farm for both simplified and realistic wind conditions. A new analytical wake model (Jensen-Gaussian model) taking into account the wake velocity variation in the radial direction was employed for the optimization study. The means of handling the irregular real wind farm boundary were proposed to guarantee that the optimized wind turbine positions are feasible within the wind farm boundary, and the discretization method was applied for the evaluation of wind farm power output under Weibull distribution. By investigating the wind farm layout optimization under different wind conditions, it showed that the total wind farm power output increased linearly with an increasing number of wind turbines. Under some particular wind conditions (e.g., constant wind speed and wind direction, and Weibull distribution), almost the same power losses were obtained under the wake effect of some adjacent wind turbine numbers. A common feature of the wind turbine placements regardless of the wind conditions was that they were distributed along the wind farm boundary as much as possible in order to alleviate the wake effect.

Design Analysis of Critical Concepts Influence Wind Farm Production and Efficiency

Wind farm deficiency caused by wake turbine interactions has received an important attention by scientific researchers in recent years. However the quality of power production is strongly depends on wind turbines location from others. In this regard, this paper proposes a comprehensive design analysis of crucial concepts that aid to plan for an efficient wind farm design. Indeed, the wake modeling problem is addressed in this analysis by comparing three models with available measured data gotten from literature. A configuration of wind turbines placement within the offshore wind farm as a function of separation distance is investigated in this study considering four wind farms layout. In addition to these elements, four rotor diameters size are evaluated as critical concept for wind turbine selection and production .The results obtained demonstrate that it is complicated to make a balance between three conflicted objectives related to the power production, efficiency and surface land area required for wind farm as a function of these crucial concepts.

Impact of model uncertainties on the fatigue reliability of offshore wind turbines

The impact of environmental load uncertainties on the spatial fatigue reliability of offshore wind turbine foundations is discussed and exemplified. Design procedures are utilizing overall or partial safety factors to include different model- and statistical uncertainties. Uncertainties in the final design are related to decisions taken during the design process, such as; load models, analysis methods and statistical descriptions. Furthermore, to benefit from more elaborate methods, strategies to account for reduced uncertainties by increased knowledge must be adopted. This is especially important for the offshore wind energy industry, where the aim is to produce renewable energy at a competitive cost level. The challenges and consequences of using a detailed design basis are exemplified and discussed through structural reliability analyses. Epistemic load effect uncertainties related to the foundation fatigue will be presented for a detailed wind directional model, wind-wave misalignment, and a second order wave load model. It will be shown that all of these represent important uncertainties to consider during the fatigue design of an offshore wind farm.

Research on Wind Power Equipment Selection System Based on Axiomatic and Knowledge

With the changes of product market requirement and fierce competition, there are kinds of wind power equipments. Combined with the current situation and development trend of wind power enterprise, the establishment of wind power equipment selection system for wind farm design would be proposed and researched. Axiomatic design method is adopted to realize express of customer requirement analysis, and mapping relationship between function demands and design parameters are researched. Wind power equipment selection model based on knowledge is adopted and studied, the reuse of resource is actualized mostly by management of model information and knowledge. Axiomatic design method is adopted to design the platform system, and wind power equipment selection system structure would be established by the method, knowledge of related field and wind power equipment selection process are embed in the system. The reusability method for wind power equipment selection is researched, which realized the reuse of model, information, data and knowledge for wind power equipment selection process. The system structure of wind power equipment selection for wind farm design will be established by the above theories and methods, which would improve wind power equipment selection effectively.

Offshore Wind Farms as Potential Locations for Flat Oyster (Ostrea edulis) Restoration in the Dutch North Sea

The “Dutch Energy Agreement” motivates governments and industries to invest in renewable energy sources, of which offshore wind energy is one of the solutions to meet the agreed target of 16% of the total energy budget from renewable resources by 2023. An option for the multi-use of wind farms is nature-inclusive building, in which the design and construction of wind farms make use of the potential for co-design with oyster bed restoration. This can support the government’s ambitions, for the Dutch North Sea, to achieve biodiversity goals, restore ecosystem functions, and enhance ecosystem services, including future seafood production. For the recovery of flat oyster (Ostrea edulis) beds, knowledge is required about the conditions under which active restoration of this species in the North Sea can be successfully implemented. This paper gives a framework and presents results to determine suitability of wind farms for flat oyster restoration, and provides recommendations for pilot studies. Our analysis showed that a number of wind farms in the Dutch section of the North Sea are suitable locations for development of flat oyster beds. Combining oyster restoration and oyster culture, as a protein source, is a viable option worth investigating.

Winds of Change: How Up-To-Date Forecasting Methods Could Help Change Brazilian Wind Energy Policy and Save Billions of US$

This paper proposes a revaluation of the Brazilian wind energy policy framework and the energy auction requirements. The proposed model deals with the four major issues associated with the wind policy framework that are: long-term wind speed sampling, wind speed forecasting reliability, energy commercialization, and the wind farm profitability. Brazilian wind policy, cross-checked against other countries policies, showed to be too restrictive and outdated. This paper proposes its renewal, through the adoption of international standards by Brazilian policy-makers, reducing the wind time sampling necessary to implement wind farms. To support such a policy change, a new wind forecasting method is designed. The method is based on fuzzy time series shaped with a statistical significance approach. It can be used to forecast wind behavior, by drawing the most-likely wind energy generation intervals given a confidence degree. The proposed method is useful to evaluate a wind farm profitability and design the biding strategy in auctions.

An Optimization Framework for Wind Farm Design in Complex Terrain

Designing wind farms in complex terrain is an important task, especially for countries with a large portion of complex terrain territory. To tackle this task, an optimization framework is developed in this study, which combines the solution from a wind resource assessment tool, an engineering wake model adapted for complex terrain, and an advanced wind farm layout optimization algorithm. Various realistic constraints are modelled and considered, such as the inclusive and exclusive boundaries, minimal distances between turbines, and specific requirements on wind resource and terrain conditions. The default objective function in this framework is the total net annual energy production (AEP) of the wind farm, and the Random Search algorithm is employed to solve the optimization problem. A new algorithm called Heuristic Fill is also developed in this study to find good initial layouts for optimizing wind farms in complex terrain. The ability of the framework is demonstrated in a case study based on a real wind farm with 25 turbines in complex terrain. Results show that the framework can find a better design, with 2.70% higher net AEP than the original design, while keeping the occupied area and minimal distance between turbines at the same level. Comparison with two popular algorithms (Particle Swarm Optimization and Genetic Algorithm) also shows the superiority of the Random Search algorithm.

Large-eddy simulation of a utility-scale wind farm in complex terrain

Site-specific wind farm design must take into account the effects of site-specific terrain topography. Large-eddy simulation (LES) is a promising approach for simulating the site-specific characteristics of the wind fields and turbine wakes in complex terrain. However, to the best of our knowledge, the capability of LES in simulating utility-scale wind farms in complex terrain has not been systematically evaluated. In this work, we apply the state-of-art LES code Virtual Flow Simulator (VFS-Wind) to simulate the Invenergy Vantage wind farm (located in the Washington state, USA) in complex terrain. The computed power outputs are compared with field measurements and good agreement with the measured data is obtained both in terms of mean power and statistics of power generated by the wind farm. A simple analytical wind farm model without considering the complex terrain effects is also applied to predict the performance of the Vantage wind farm layout. The results show that such a model overestimates the performance of the actual Vantage wind farm and underscore the need for developing analytical models that account for terrain effects to enable wind farm design and optimization in complex terrain. LES can provide the data sets required to calibrate and validate such terrain-specific analytical models.

Comparative study of discretization method and Monte Carlo method for wind farm layout optimization under Weibull distribution

The wind farm layout optimization is an effective tool to alleviate the wake power losses caused by wind turbine interactions in a wind farm. It is widely recognized that for a real wind farm site with abundant wind resources, wind speed variation of the wind condition can be approximated by the Weibull distribution, which therefore needs to be incorporated into the power evaluation of a real wind farm design. Current researchers have employed the discretization method by dividing the wind speed region into bins to calculate the power output of wind turbines under Weibull distribution, which has two main drawbacks including: 1) complicated discretization process with large computational cost and 2) dependency of calculation accuracy on the discretization resolution. This paper aims to propose a new Monte Carlo method to evaluate the wind farm power output under Weibull distribution, and verify the effectiveness and efficiency of the new method by comparison to the widely used discretization method. Through reducing the wind speed discretizing interval, it is found that when the discretized wind speed interval is smaller than 0.1 m/s, the improvement of optimization results is negligible while the computational cost significantly increases for the discretization method. By testing different sample numbers, it is found that selecting 100000 samples for the Monte Carlo method calculation is able to achieve accurate results with less computational cost than the discretization method especially when large number of turbines is installed in the wind farm. In conclusion, the Monte Carlo method greatly facilitates the power evaluation of wind farm layout optimization under Weibull distribution, with a balance between the calculation accuracy and the computational cost.