一种新型双电池风力发电储能系统及控制策略

提出一种新型双电池风电储能系统,它能以较低的运行成本将风电功率波动维持在规定的范围内;风电场可在每个调度时段内输出恒定功率,使风电稳定地并入电网。当调度功率低于实际风电功率时,起充电作用的电池处于工作状态,当调度功率高于实际风电功率时,起放电作用的电池处于工作状态;当其中一个电池充满电或深度放电时,2组电池的充、放电状态切换。为了延长电池使用寿命,对调度功率进行优化,以确保2组电池都在完整充、放电循环下运行,此双电池储能系统可显著降低系统运行成本。利用一台具有真实风电功率数据的3 MW风电机组进行仿真分析,验证了所提系统及控制策略的有效性。     

Sensitivity of southern California wind energy to turbine characteristics

Using output from a high‐resolution meteorological simulation, we evaluate the sensitivity of southern California wind energy generation to variations in key characteristics of current wind turbines. These characteristics include hub height, rotor diameter and rated power, and depend on turbine make and model. They shape the turbine's power curve and thus have large implications for the energy generation capacity of wind farms. For each characteristic, we find complex and substantial geographical variations in the sensitivity of energy generation. However, the sensitivity associated with each characteristic can be predicted by a single corresponding climate statistic, greatly simplifying understanding of the relationship between climate and turbine optimization for energy production. In the case of the sensitivity to rotor diameter, the change in energy output per unit change in rotor diameter at any location is directly proportional to the weighted average wind speed between the cut‐in speed and the rated speed. The sensitivity to rated power variations is likewise captured by the percent of the wind speed distribution between the turbines rated and cut‐out speeds. Finally, the sensitivity to hub height is proportional to lower atmospheric wind shear. Using a wind turbine component cost model, we also evaluate energy output increase per dollar investment in each turbine characteristic. We find that rotor diameter increases typically provide a much larger wind energy boost per dollar invested, although there are some zones where investment in the other two characteristics is competitive. Our study underscores the need for joint analysis of regional climate, turbine engineering and economic modeling to optimize wind energy production. Copyright © 2012 John Wiley & Sons, Ltd.     

Valuing the manufacturing externalities of wind energy: assessing the environmental profit and loss of wind turbines in Northern Europe

This study draws from a concept from green accounting, lifecycle assessment, and industrial ecology known as 'environmental profit and loss” (EP&L) to determine the extent of externalities across the manufacturing lifecycle of wind energy. So far, no EP&Ls have involved energy companies and none have involved wind energy or wind turbines. We perform an EP&L for three types of wind turbines sited and built in Northern Europe (Denmark and Norway) by a major manufacturer: a 3.2 MW onshore turbine with a mixed concrete steel foundation, a 3.0 MW offshore turbine with a steel foundation, and a 3.0 MW offshore turbine with a concrete foundation. For each of these three turbine types, we identify and monetize externalities related to carbon dioxide emissions, air pollution, and waste. We find that total environmental losses range from €1.1 million for the offshore turbine with concrete foundation to €740,000 for onshore turbines and about €500,000 for an offshore turbine with steel foundation—equivalent to almost one‐fifth of construction cost in some instances. We conclude that carbon dioxide emissions dominate the amount of environmental damages and that turbines need to work for 2.5 to 5.5 years to payback their carbon debts. Even though turbines are installed in Europe, China and South Korea accounted for about 80% of damages across each type of turbine. Lastly, two components, foundations and towers, account for about 90% of all damages. We conclude with six implications for wind energy analysts, suppliers, manufacturers, and planners. Copyright © 2015 John Wiley & Sons, Ltd.     

Assessment of wind characteristics and wind turbine characteristics in Taiwan

Wind characteristics and wind turbine characteristics in Taiwan have been thoughtfully analyzed based on a long-term measured data source (1961–1999) of hourly mean wind speed at 25 meteorological stations across Taiwan. A two-stage procedure for estimating wind resource is proposed. The yearly wind speed distribution and wind power density for the entire Taiwan is firstly evaluated to provide annually spatial mean information of wind energy potential. A mathematical formulation using a two-parameter Weibull wind speed distribution is further established to estimate the wind energy generated by an ideal turbine and the monthly actual wind energy generated by a wind turbine operated at cubic relation of power between cut-in and rated wind speed and constant power between rated and cut-out wind speed. Three types of wind turbine characteristics (the availability factor, the capacity factor and the wind turbine efficiency) are emphasized. The monthly wind characteristics and monthly wind turbine characteristics for four meteorological stations with high winds are investigated and compared with each other as well. The results show the general availability of wind energy potential across Taiwan.     

A bold effort in Vermont [History]

Soon after building his summer house on Cape Cod, Massachusetts, in 1934, Palmer Cosslett Putnam found that both the prevailing winds and his electric utility bills were surprisingly high. He reasoned that a wind turbine producing ac electricity could reduce his electric bills if the local electric utility remained available to maintain service when there was no wind and would also accept into its system excess electrical energy generated by the wind turbine. Putnam's calculations showed that the small wind-driven electric generators then available would be unable to supply the peak load requirements of his house. With his interest in wind power thus aroused, Putnam embarked on a pioneering project that would result in the design, construction, testing, and operation of the first megawatt-size wind turbine and one of the earliest to be integrated into an electric utility system. In advancing windproduced electrical energy knowledge and technology, the Smith-Putnam wind turbine became an important forerunner of today's large wind turbine designs for the production of electrical energy.     

Estimating the potential yield of small building‐mounted wind turbines

The wind profile in the urban boundary layer is described as following a logarithmic curve above the mean building height and an exponential curve below it. By considering the urban landscape to be an array of cubes, a method is described for calculating the surface roughness length and displacement height of this profile. Firstly, a computational fluid dynamics (CFD) model employing a k‐? turbulence model is used to simulate the flow around a cube. The results of this simulation are compared with wind tunnel measurements in order to validate the code. Then, the CFD model is used to simulate the wind flow around a simple pitched‐roof building, using a semi‐logarithmic inflow profile. An array of similar pitched‐roof houses is modelled using CFD to determine the flow characteristics within an urban area. Mean wind speeds at potential turbine mounting points are studied, and optimum mounting points are identified for different prevailing wind directions. A methodology is proposed for estimating the energy yield of a building‐mounted turbine from simple information such as wind atlas wind speed and building density. The energy yield of a small turbine on a hypothetical house in west London is estimated. The energy yield is shown to be very low, particularly if the turbine is mounted below rooftop height. It should be stressed that the complexity of modelling such urban environments using such a computational model has limitations and results can only be considered approximate, but nonetheless, gives an indication of expected yields within the built environment. Copyright © 2007 John Wiley & Sons, Ltd.     

一种新型聚能-遮蔽型立轴风力机

提出了一种适合任意风向的新型聚能-遮蔽型立轴风力机,并应用计算流体力学方法,对这种风力机的气动性能进行了数值模拟.研究表明:这种新型立轴风力机比传统的立轴风力机的风能利用率有显著提高.此外,该文还采用了正交优化设计方法,对这种立轴风力机的结构参数进行了优化设计,得到了一组最优的设计参数,该最优设计参数下风力机的风能利用率达37%.     

大型风力发电场选址与风力发电机优化匹配

从风能利用和风电成本两个角度出发,推导出风电场选址与风力机优化选型的目标函数,提出将风力机容量系数作为风电场选址与风力机选型的判据,同时给出了基于风速分布特性的风力机容量系数计算方法。通过我国云南省的13个实际风速观测点和国内外25种风力机代表机型的计算,给出了这些观测点的开发顺序及优化配置的风力机机型,并简要分析了影响风力机容量系数的主要因素。实践表明,这种方法物理意义明确,计算快捷方便,节省设计时间和设计工作量。     

Wind plant power optimization through yaw control using a parametric model for wake effects—a CFD simulation study

This article presents a wind plant control strategy that optimizes the yaw settings of wind turbines for improved energy production of the whole wind plant by taking into account wake effects. The optimization controller is based on a novel internal parametric model for wake effects called the FLOw Redirection and Induction in Steady‐state (FLORIS) model. The FLORIS model predicts the steady‐state wake locations and the effective flow velocities at each turbine, and the resulting turbine electrical energy production levels, as a function of the axial induction and the yaw angle of the different rotors. The FLORIS model has a limited number of parameters that are estimated based on turbine electrical power production data. In high‐fidelity computational fluid dynamics simulations of a small wind plant, we demonstrate that the optimization control based on the FLORIS model increases the energy production of the wind plant, with a reduction of loads on the turbines as an additional effect. Copyright © 2014 John Wiley & Sons, Ltd.     

变桨距提高升力型垂直轴风力机性能研究综述

风能是世界存量大、绿色无污染的可再生能源之一。由于风力机旋转工况复杂,翼型的相对攻角变化剧烈,导致翼型容易失速,风机的风能利用率低。变桨距主动控制技术是目前最常用的提高升力型垂直轴风力机性能的方法。针对近年来变桨距技术的最新研究进展情况进行了综述。通过全面的文献检索和阅读,总结和阐述了不同变桨距控制策略的设计与实现方法,并分析了不同变桨距技术的优缺点。     

独立运行风电机组的最佳叶尖速比控制

介绍了采用爪极无刷自励发电机的５ｋＷ风电机组的性能特点。采用最佳叶尖速比控制和稳压控制相结合的控制方法，使风力机在额定风速以下及蓄电池没有充满时按最佳效率运行。当蓄电池接近充满时，控制风电系统稳压运行，保证蓄电池安全可靠充电。该风电机组及其控制已实际应用。     

Effect of winds in a mountain pass on turbine performance

Mountain passes are potentially advantageous sites for the deployment of wind turbines because of road links and electrical transmission infrastructure. However, relatively little is known about wind characteristics and turbine response in these environments. Using hub height wind data from a mountain pass in Switzerland, this paper discusses the causes of the observed pass winds and how a generic wind turbine might perform in those conditions. During 3 months of winter measurements, the winds in the pass showed signatures of forcing by regional pressure gradients rather than local cooling or heating. Turbulence intensity was often less than 10%, and the magnitude of the wind shear power law exponent was less than 0.1. To understand the impact of pass winds on a wind turbine, we simulated a Wind Partnership for Advanced Component Technologies 1.5 MW wind turbine using the Fatigue, Aerodynamics, Structures, and Turbulence (FAST) aeroelastic simulator , forced by artificial wind fields of varying turbulence intensity and shear generated by the turbulence simulator TurbSim. We used the turbine simulation data to train a regression model that is used to predict the turbine response to the pass wind time series. Results showed that depending on long‐term wind characteristics, wind turbines in the pass may perform differently than predicted using a power curve derived from test measurements at another location. This method of generating site‐specific energy capture predictions could be combined with long‐term wind resource data and specific turbine models to better predict the energy production and turbine loads at this, or any other site. Copyright © 2013 John Wiley & Sons, Ltd.     

Wind turbine fatigue loads as a function of atmospheric conditions offshore

In recent years, there has been a growing interest by the wind energy community to assess the impact of atmospheric stability on wind turbine performance; however, up to now, typically, stability is considered in several distinct arbitrary stability classes. As a consequence, each stability class considered still covers a wide range of conditions. In this paper, wind turbine fatigue loads are studied as a function of atmospheric stability without a classification system, and instead, atmospheric conditions are described by a continuous joint probability distribution of wind speed and stability. Simulated fatigue loads based upon this joint probability distribution have been compared with two distinct different cases, one in which seven stability classes are adopted and one neglecting atmospheric stability by following International Electrotechnical Commission (IEC) standards. It is found that for the offshore site considered in this study, fatigue loads of the blade root, rotor and tower loads significantly increase if one follows the IEC standards (by up to 28% for the tower loads) and decrease if one considers several stability classes (by up to 13% for the tower loads). The substantial decrease found for the specific stability classes can be limited by considering one stability class that coincides with the mean stability of a given hub height wind speed. The difference in simulated fatigue loads by adopting distinct stability classes is primarily caused by neglecting strong unstable conditions for which relatively high fatigue loads occur. Combined, it is found that one has to carefully consider all stability conditions in wind turbine fatigue load simulations. Copyright © 2016 John Wiley & Sons, Ltd.     

Accounting for the speed shear in wind turbine power performance measurement

The current IEC standard for wind turbine power performance measurement only requires measurement of the wind speed at hub height assuming this wind speed to be representative for the whole rotor swept area. However, the power output of a wind turbine depends on the kinetic energy flux, which itself depends on the wind speed profile, especially for large turbines. Therefore, it is important to characterize the wind profile in front of the turbine, and this should be preferably achieved by measuring the wind speed over the vertical range between lower and higher rotor tips. In this paper, we describe an experiment in which wind speed profiles were measured in front of a multimegawatt turbine using a ground–based pulsed lidar. Ignoring the vertical shear was shown to overestimate the kinetic energy flux of these profiles, in particular for those deviating significantly from a power law profile. As a consequence, the power curve obtained for these deviant profiles was different from that obtained for the ‘near power law’ profiles. An equivalent wind speed based on the kinetic energy derived from the measured wind speed profile was then used to plot the performance curves. The curves obtained for the two kinds of profiles were very similar, corresponding to a significant reduction of the scatter for an undivided data set. This new method for power curve measurement results in a power curve less sensitive to shear. It is therefore expected to eventually reduce the power curve measurement uncertainty and improve the annual energy production estimation. Copyright © 2011 John Wiley & Sons, Ltd.     

Hybrid (solar and wind) energy system for Al Hallaniyat Island electrification

Wind–PV–diesel hybrid power generation system technology is a promising energy option since it provides opportunities for developed and developing countries to harness naturally available, inexhaustible and pollution-less resources. The aim of this study is to assess the techno-economic feasibility of utilizing a hybrid wind–PV–diesel power system to meet the load of Al Hallaniyat Island. Hybrid Optimization Model for Electric Renewables software has been employed to carry out the present study. The simulation results indicate that the cost of generating energy (COE) is $0.222 kWh^?1 for a hybrid system composed of a 70 kW PV system, 60 kW wind turbine and batteries together with a 324.8 kW diesel system. Moreover, using the same system but without batteries will increase the COE to $0.225 kWh^?1, the fuel consumption, the excess energy and the total operating hours for the diesel generators. The PV–wind hybrid option is techno-economically viable for rural electrification.     

聚风导流型立轴风力机设计及气动性能分析

针对传统的立轴风力机风能利用率低的问题,应用正交优化法和流场数值模拟技术对聚风导流型立轴风力机的结构设计参数进行了优化设计。在同尺度下与传统立轴风力机进行了对比分析。结果表明,聚风导流型立轴风力机叶轮的输出功率、风能利用率及自启动特性均得到了显著提高。     

Dynamic evaluation of two configurations for a hybrid DFIG‐based wind turbine integrating battery energy storage system

Hybrid systems comprising battery energy storage systems (BESSs) and wind power generation entail considerable advances on the grid integration of renewable energy. Doubly fed induction generators (DFIGs) stand out among different wind turbine (WT) technologies. On the other hand, electrochemical batteries have proved to be valid for these purposes. In this paper, a comparative analysis is carried out between two alternative configurations for hybrid WT‐BESS systems, where the BESS is connected either outside or inside the DFIG. The modeling of these two configurations and the control systems applied for achieving the coordinate operation of the energy sources (DFIG and batteries) are illustrated. The hybrid systems under study are evaluated by simulation under normal operation (wind speed fluctuations and grid demand changes) and grid faults. Simulation results show that both configurations improve the grid integration capability of the WT, although the configuration with external BESS presents better results since it can provide additional active/reactive power injection. Copyright © 2014 John Wiley & Sons, Ltd.     

一种评价风电场设计水平的新方法

提出了一种独立于当地风资源、基于实际设计水平来评价风电场设计水平的新方法。根据影响发电量的主要设计因素,引入衡量风电机组的选型和布置的3个新指标:风电场发电效率、风电机组容量系数和风电机组布置系数,并推导出这3个系数的表达式。提出的3个新指标具有明确的物理意义,可以定量评价风电场风电机组选型和布置对风电场设计水平的影响。最后对两个实际风电场进行了计算和分析,所得结果的正确性得到风电场实际运行调研和后评价的验证。该方法不仅提出了较全面的对风电场设计水平的评价方法,而且可以进行量化评分,对风电场的设计具有重要的理论意义和经济价值。     

Wind farm voltage dip measurements

This paper is based on continuous measurements of voltages and currents from three wind farms for a period of 1 year, and the focus is on voltage dips. The purpose is to get an overview of the characteristics and rate of voltage dips, which occur in the wind farms and to study the wind turbine responses to voltage dips. In each of the wind farms there is one measurement point at a single wind turbine and one for measuring the contribution from the whole wind farm. Different wind turbine technologies are used in the three wind farms; fixed speed turbines with directly connected induction generators in wind farm 1 and variable speed turbines with power electronics converters and synchronous generators in wind farms 2 and 3. Voltage dips are evaluated according to the standard EN 50160, by considering the durations and residual voltages of the positive sequence component voltage dips. Some examples of voltage dip events with corresponding responses in active and reactive power are shown and discussed with a view to the different technologies. Copyright © 2013 John Wiley & Sons, Ltd.     

Implications of seasonal and diurnal variations of wind velocity for power output estimation of a turbine: a case study of Grenada

This case study highlights the importance of taking into consideration diurnal variations of wind velocity for wind energy resources assessment. Previous studies of wind energy distribution that are based on the two-parameter Weibull density function have so far neglected to consider time of day fluctuations in wind speed, instead concentrating primarily on seasonal deviations. However, this has serious implications where such a wind energy model is the underpinning of calculations for the potential power production from a wind turbine and in particular where the timing of the energy output is essential to meet electricity loads. In the case of Grenada the energy output from a wind turbine during the day is approximately two times the output at night thereby fluctuating enormously around the seasonal mean distribution. When this is not taken into account the economic and technological viability of a wind turbine project may be overestimated or not even be identified. This work shows how a wind energy resources assessment based on the Weibull distribution model can be done and how the power output of a horizontal axis turbine is calculated. An analysis of the recorded wind data confirms the application of the Weibull density function as a suitable tool for modelling wind regimes. Copyright © 2003 John Wiley & Sons, Ltd.