Wind Turbine Power Generation Research Articles

Potential contribution of wind energy to climate change mitigation

The increased use of wind turbines for power generation could play an important role in climate change mitigation efforts. This study shows that, assuming greenhouse gas emissions are kept in check and energy-use efficiency increases, crossing the 2 °C warming threshold could be significantly delayed or even avoided altogether depending on how aggressively wind energy is taken up over coming decades.

Potential for wind energy generation in Piracicaba, SP, Brazil

Wind power has gained space in Brazil's energy matrix, being a clean source and inexhaustible. Therefore, it becomes important to characterize the wind potential of a given location, for future applications. The main objective of the present study was to estimate the wind energy potential in Piracicaba, SP, Brazil. The wind speed data were collected by an anemometer installed at the Meteorological Station Luiz de Queiroz College of Agriculture, Piracicaba-SP. The wind speed variability was represented by the Weibull frequency distribution, a probability density function of two parameters (k and c). The parameters k and c were used to correlate the Gamma function with the annual average wind speed, the variance and power mean density. A wind profile was made to evaluate the behavior of historical average speeds at higher altitudes measured by anemometer, to estimate the gain in power density. The values of k for all heights were close to 1 which corresponds to a wind regime highly variable, and c values were also low representing a low average speed of the location. The location was characterized as being unfavorable for the application of wind turbines for power generation.

횡류형 터빈을 적용한 수직축 풍력발전시스템의 성능평가를 위한 실험 연구

본 최근 성장하고 있는 해상 풍력의 실험연구에서 풍동시험이 수직형 횡류 풍력발전시스템의 성능을 조사하기 위해 실시되었다. 풍동의 시험 부분은 제한된 크기로 인해 실제 풍력 발전의 입구 안내 베인을 약 1/5로 축소시켰고, 터빈 임펠러의 지름을 모형 임펠러의 1/2로 감소시켰다. 임펠러 블레이드 갯수는 풍력 발전 시스템의 출력에 대한 또 다른 중요한 변수이기 때문에 8개와 16개로 변경하여 시험하였다. 실험 분석 결과, 모형 풍력 터빈의 출력 제동력은 정격 풍속 12m/s에서 블레이드 갯수가 8개 보다 16개일 때 82% 출력이 증가된 278와트로 측정되었고, 정격 제동력은 정격 작동 조건에서 3.9kW로 계산되었다. In this experimental study for the current growing offshore wind, a wind tunnel test was conducted to examine the performance of the vertical-type cross-flow wind turbine power generation system. Due to the limited size of the test section of the wind tunnel, the inlet guide vane of the original wind power generation was scaled down to about 1/5 and the turbine impeller diameter was also reduced to 1/2 of the prototype impeller. The number of the impeller blade is another important parameter to the output power of the wind power generation system and the number was varied 8 and 16. From the analysis of the experimental result, the output brake power of the model wind turbine was measured as 278watts with the 16-blade at 12 m/s of the rated wind speed and the rated brake power of the prototype wind turbine is calculated to 3.9kW at the rated operating condition.

Reliability Evaluation of Generation and Transmission Systems Considering the Effects of Wind Farm

Because wind energy fluctuates randomly, the output power of wind turbine generators is uncertain. The reliability of power systems including wind generation is analyzed in this paper. In this paper, the reliability model of wind generators and the model of transmission network are combined by considering the sequential and autocorrelation of wind speed, the output power function and the forced outage of wind units. Then a reliability evaluation model of generation and transmission system, in which the system security constraints are satisfied, is built and the objective function is LSC. Taking IEEE-RTS96 system as an example, the reliability index which can reflect the effects of wind farms is calculated. The result provides the scientific reference for connecting wind farms to power systems.

J0540101 スマートシティを構成するビル風利用風力発電モデルの発電電力量計算([J054-01]再生可能エネルギー(1),流体工学部門)

The aim of this study is to design and propose the size and layout of buildings which provide the better wind distribution for the higher power generation of wind turbine. A building model whose layout is like nozzle is proposed to obtain the acceleration of wind blowing through buildings due to contracted flow between buildings, hi addition, the effect of the angle between two buildings on the power generation performance of the proposed building model is also investigated. For the feasibility check of installing the building model in some area actually, the power energy of wind turbine is investigated by considering the meteorological data such as wind velocity and direction distribution for Fukushima city as an example. If the proposed building model whose angle between two buildings is 135 degree is installed in Fukushima city, the ratio of power energy generated by wind turbine to electric consumption of households in a year is estimated to be approximately 21-22%.

Optimization of production and maintenance problem: Case study of wind turbine power generation

W turbine system reliability is a critical factor in the success of a wind energy project. Consequently, maintenance is a crucial issue for such projects. In this paper, an integrated production and periodic maintenance policy with minimal repair at failures is proposed for a hybrid power generation system. We seek to establish an optimal integrated electricity production and maintenance plan over a finite planning horizon. It is important to do so according to the wind speed profile in order to guarantee that a random power demand (consumption) is satisfied given a target service level. In the context of energy planning, many researchers presented several techniques and methods which provide solutions to the multi-objective optimization problem for energy planning decisions. They have observed that Analytical Hierarchy Process (AHP) is the most popular technique followed by outranking techniques Promethee and Electre. Regarding renewable power generation systems reliability, some researchers studied the factors that contribute to the reliability deterioration of such systems; they concluded that in a significant part of the year, seasonal and spatial variability of wind, and to a lesser extent that of solar energy can yield low availability leading to an increase in unserved energy. Based on these literature reviews, we propose in this talk an integrated production-maintenance policy for wind turbine power generation. In fact, our approach consists in determining the best combination of energy production and maintenance effort, which minimizes the total cost while satisfying a random demand during a finite horizon with a given service level. This study is inspired from the background work, which models the influence of the production rate on the degradation level of the production system, and consequently on the maintenance strategy. A numerical example illustrates the use of the developed mathematical model.

Wake-effect Minimising Optimal Control of Wind Farms, with Load Reduction

A power generating wind turbine causes a speed reduction and an added turbulence to the wind. Wind turbines in wind farms are often caught in these wakes and are found to have a higher structural load than non affected wind turbines. This article investigates the possibility of designing a control strategy which optimizes the power production, while minimizing the effect of the wakes in the wind farm.A generic wind farm model which is able to calculate the wind turbines influence on each other is developed. Models for the reduction in wind speed as well as turbulence in the wake effects are developed in order to simulate the wake effects. The models are of low complexity, making the wind farm model suitable for control purposes.A model predictive wind farm controller (MPC) is developed and compared to a classical wind farm controller. The MPC is developed, with the ability to minimize the wake effects in the farm, while maintaining optimal power output. A feature which enables the MPC to spare certain turbines, while maintaining the power output is also implemented. The MPC controller is able to minimize the wake effect in the wind farm, when the power demand is not using the full potential of the wind farm.

Design and implementation of a grid‐tied wind power micro‐inverter

Small wind turbine generator (WTG) below 300 W capacity is suitable to generate power in residential or city area, where no large space for installing kilowatt scale WTG. The modularised micro-inverter which can feed WTG power to the grid directly has the merit of increasing the installed flexibility and omitting the battery in this application. This study proposes a grid-tied micro-inverter combining the boost and flyback-based inverter topology and specially designed for the small WTG with permanent magnetic (PM) generator. The boost converter is used to step up the input voltage and track the maximum power point (MPP) of the WTG. The flyback-based inverter is used to feed power to the grid with unity power factor. A fast MPP tracking (MPPT) method is presented to track the wind power to fit for the wind speed with fast variation. The variable frequency peak current mode control method is adopted for the control of the flyback-based inverter. An interleaving technique is also applied to the inverter for increasing its power capacity. Quantitative controller design of the boost converter with the WTG input and the grid-tied flyback-based inverter is presented. A 240 W experimental system is built. A WTG emulator implemented with the M–G set is developed for testing the proposed system. Some simulation and measured results are provided for demonstrating the effectiveness of the proposed system.

An optimal design of coreless direct-drive axial flux permanent magnet generator for wind turbine

Different types of generators are currently being used in wind power technology. The commonly used are induction generator (IG), doubly-fed induction generator (DFIG), electrically excited synchronous generator (EESG) and permanent magnet synchronous generator (PMSG). However, the use of PMSG is rapidly increasing because of advantages such as higher power density, better controllability and higher reliability. This paper presents an innovative design of a low-speed modular, direct-drive axial flux permanent magnet (AFPM) generator with coreless stator and rotor for a wind turbine power generation system that is developed using mathematical and analytical methods. This innovative design is implemented in MATLAB / Simulink environment using dynamic modelling techniques. The main focus of this research is to improve efficiency of the wind power generation system by investigating electromagnetic and structural features of AFPM generator during its operation in wind turbine. The design is validated by comparing its performance with standard models of existing wind power generators. The comparison results demonstrate that the proposed model for the wind power generator exhibits number of advantages such as improved efficiency with variable speed operation, higher energy yield, lighter weight and better wind power utilization.

The Impact of Solid State Fault Current Limiter on Power Network With Wind-Turbine Power Generation

In this paper, it is aimed to investigate the impact of the various solid-state fault current limiters (SSFCLs) on several electric power networks with the wind-turbine power generation (WTPG). Distributed generations (DGs) are predicted to perform an increasing role in the future electrical power system. Expose of the DG, can change the fault current during a grid disturbance and disturb the existing distribution system protection. Fault current limiters (FCLs) can be sorted into L-types (inductive) and R-types (resistive) by the fault current limiting impedance. In this paper, a new SSFCL has been proposed. SSFCLs can provide the fast system protection during a rigorous fault. The act of dynamic damping enhancement via the SSFCL is appraised in the presence of the wind-turbine power generation. Hence, its efficiency as a protective device for the wind-turbine system is confirmed via some case studies by time-domain simulation based on the PSCAD/EMTDC.

Implementing wind turbines in a tall building for power generation: A study of wind loads and wind speed amplifications

Pearl River Tower, located in Guangzhou, has 71 stories and rises about 310m from the ground, which features four open holes (tunnels) equipped with four wind turbines at mechanical floors on two height levels. This study investigated the wind loads on the tall building and the wind speed up factors in the tunnels for wind-power generation based on wind tunnel tests and wind climate data analysis. Wind-induced pressures and overall forces on the building model with a geometric scale of 1:150, including the mean and fluctuating components, were determined and the wind speed amplifications in the tunnels were measured in the wind tunnel tests. Comparative analysis and discussions of the results for four cases were conducted. The objective of this study is to evaluate the wind speed amplifications in the tunnels for wind-power generation through the installation of wind turbines and to gain a better understanding of the wind effects on such a high-rise building with open holes. The results presented in this paper are expected to be of considerable interest and practical use to engineers and researchers involved in the design of tall buildings incorporating wind turbines for power generation.

A benefits analysis for wind turbine allocation in a power distribution system

This paper proposes an algorithm to analyze the long-term benefits of Wind Turbine (WT) allocation at the demand side of a power distribution system. The benefits are evaluated based on the wind electricity generation and the avoidance of CO2 emissions. The objective function includes the investment cost, maintenance cost, and the cost of loss reduction, subjective to operating limits and line flow constraints. Taking load growth into account, Particle Swarm Optimization (PSO) with a power flow algorithm is proposed to solve this problem. To enhance the performance of the optimization approach, a load flow model with Equivalent Current Injection (ECI) is used to analyze the power flow of distribution systems. By considering the power generation of WTs, electricity prices, and carbon trading prices, the long-term benefits of the installation of wind turbines in different scenarios are evaluated. Examples of IEEE 69-bus systems are presented to illustrate the efficiency and feasibility of the proposed algorithm. Simulation results can help decision makers in selecting the proper installation sites for WTs, as well as in determining the tradeoff between optimal investment and environmental policy for future electricity and carbon markets.

Performance of a prototype micro wind turbine in the manmade wind field from air conditioner of buildings

Harnessing waste energy from the manmade air fields of buildings presents a new area of renewable energy to explore. Due to the unpredictability of the natural wind, this study is to evaluate the practicality for harnessing waste energy from the air conditioner exhaust units which are a more constant and predictable source available in the buildings. A prototype of the micro wind turbine has been designed to minimize the negative effect of the exhaust sources. After the micro wind turbine was manufactured, the performance of the turbine was tested in the selected air conditioner exhaust unit. Increasing the rotor solidity and decreasing the resistance of the generator contribute to improved starting torque and decreased generator break in torque respectively in the design. The power generation of the micro wind turbine increases with an increase of the rotor speed. The 24-hour operation of the prototype presents an observation for both exhaust performance and power generation prediction when the prototype is mounted on the exhaust unit.

Wind Turbine Generation System With Optimized DC-Link Design and Control

This paper presents an optimized capacitance design for the dc link of a back-to-back converter for wind turbine power generation. The design method combines switching ripple and dynamic specifications to give the smallest possible dc-link capacitance and the required proportional-integral compensator for the voltage regulation. Furthermore, a novel concept to globally manage the on/off switching of back-to-back power subconverters, based on a finite-state machine, is presented. The proposed management system keeps control of the dc-link voltage for proper operation of both subconverters regardless of wind or grid conditions.

A novel small scale efficient wind turbine for power generation

A ‘proof of concept’ study of a novel wind turbine that overcomes some of the deficiencies and combines the advantages of the conventional horizontal and vertical axis wind turbines is presented in this paper. The study conducted using computational fluid dynamics and wind tunnel tests clearly demonstrate that such a proposition is feasible and a low cost, low noise, safe and easy to operate but enhanced performance wind turbine for small scale power generation in low wind speed is viable.

Construct Small-Scale Vertical Axis Wind Turbine Monitoring System by Wireless Sensor Networks

The thesis proposes to construct a small vertical axis wind turbine monitoring system by the wireless sensor measuring network. This paper uses a small vertical axis wind turbine to generate electricity, and then provide to the parking lot and street lights, but also practical to monitor the entire system. Our monitoring system is constructed by the module. This paper proposes the small vertical axis wind turbine with the blade structure can be adjusted the angle with mechanical means, which is the most important improvement. Monitoring system to monitor real-time status of the communication part of the ZigBee and Ethernet established in the remote monitoring platform and the establishment of an Access database. Our research will be expected to improve the efficiency of wind turbine power generation, increase the stability of the monitoring system and the overall cost of power generation to reduce the effect.

Wind Turbine Power Generation: Response Prediction

Abtract: The worldwide interest has been increasing about wind energy for power generation purpose due to continue increase in fuel cost and the need to have clean source of energy. Wind energy may enhance the power generation capabilities and maximize its capacity factor, inurn participate in generating power at lower cost. It has also been notice that renewable power generation through wind energy is also the fast growing energy technology. The optimization of the efficiency of wind turbine is prudent to complete the conventional power sources. Wind Turbine Power Generation (WTPG) is a complex phenomenon to understand since the real process has depends upon the Wind Velocity and the relative turbine dimensions and the outside climatological parameter like Wind Velocity (WV) nature of wind, etc. In this paper an effort has been made to develop a fuzzy logic approach to predict an appropriate WTPG considering the WV, AD and Chord Length of Turbine Blades (CLTB) as input parameters. The complexities of the parameters and the imprecision of linguistic expressions are taken into consideration; the application combining linguistic variable to optimize WTPG under multiple conditions is presented in this study.

Model for Optimal Sizing of a Wind Energy Conversion System for Green-Mobile Applications

The goal of the green-mobile technology is to attain negligible anthropogenic emissions of carbon dioxide (from the GSM base station generators), which constitute by far the largest part of the emissions of greenhouse gases, thereby making the environment much more friendly and safe. This study established the effect of altitude on the output power of wind turbine generators, and proposed a robust model to account for this effect is proposed for optimal sizing of a wind energy conversion system (WECS) for green-mobile applications. The proposed model implementation using a perfectly fitted polynomial expression derived from the manufacturer's power profile. Adjustment of the observed mean wind speed data to a 75 m lattice tower of a mobile station indicates that the proposed model can be effectively powered by mean wind speed for three different locations (Abuja, Benin City, and Katsina) in Nigeria. Analysis indicates that WECS, with its turbine is placed at an altitude of 100 m, loses approximately 1% of its output power.

Dynamic Optimization of Drivetrain Gear Ratio to Maximize Wind Turbine Power Generation—Part 1: System Model and Control Framework

Wind is considered to be one of the most promising resources in the renewable energy portfolio. Still, to make wind energy conversion more economically viable, it is necessary to extract greater power from the wind while minimizing the cost associated with the technology. This is particularly important for small wind turbines, which have the highest cost per kilowatt of energy produced. One solution would be a variable ratio gearbox (VRG) that can be integrated into the simple and low-cost fixed-speed induction generator. Through discrete variable rotor speed operation, the VRG-enabled system affects the wind speed ratio, the power coefficient, and ultimately the power produced. To maximize electrical production, mechanical braking is applied during the normal operation of the wind turbine. A strategy is used to select gear ratios (GRs) that produce torque slightly above the maximum amount the generator can accept while simultaneously applying the mechanical brake, so that full load production may be realized over greater ranges of the wind speed. To characterize the performance of the system, a 100 kW, fixed speed, stall-regulated wind turbine, has been developed for this study. The VRG-enabled wind turbine control system is presented in two papers. Part 1 focuses on the turbine simulation model, which includes the rotor, VRG-enabled drivetrain, disk brake, and electric generator. A technique for estimating the performance of a disk brake, in the wind turbine context, is also presented. Part 2 of the research will present a dynamic optimization algorithm that is used to establish the control protocol for competing performance objectives.

Dynamic Optimization of Drivetrain Gear Ratio to Maximize Wind Turbine Power Generation—Part 2: Control Design

The cost of electrical power produced by small wind turbines impedes the use of this technology, which can otherwise provide power to millions of homes in rural regions worldwide. To encourage their use, small wind turbines must capture wind energy more effectively while avoiding increased equipment costs. A variable ratio gearbox (VRG) can provide this capability to the simple fixed-speed wind turbine through discrete operating speeds. This is the second of a two-part publication that focuses on the control of a VRG-enabled wind turbine. The first part presented a 100 kW fixed speed, wind turbine model, and a method for manipulating the VRG and mechanical brake to achieve full load operation. In this study, an optimal control algorithm is developed to maximize the power production in light of the limited brake pad life. Recorded wind data are used to develop a customized control design that is specific to a given site. Three decision-making modules interact with the wind turbine model developed in Part 1 to create possible VRG gear ratio (GR) combinations. Dynamic programming is applied to select the optimal combination and establish the operating protocol. The technique is performed on 20 different wind profiles. The results suggest an increase in wind energy production of nearly 10%.