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采用3种不同的设计规范,对换流站4种不同形式避雷塔架进行风振系数计算;通过分析比较,得出避雷线塔风振系数的计算方法和取值标准,为今后工程设计和规程规范提供依据。 相似文献
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Wenchao Fan;Li Cai;Muzi Li;Mi Zhou;Jinxin Cao;Jianguo Wang;Yadong Fan; 《风能》2024,27(10):979-993
The upward discharge is a significant factor threatening the operation of wind farms. This paper investigates the inception and development of upward leaders of wind turbines' tip, where blade rotation prevents charge accumulation, using charge density models from laboratory discharges and artificially triggered lightning. The results indicate that larger return stroke currents create higher spatial potentials, and slower downward leader speeds allow for longer development time, favoring the development of upward leaders. As wind turbine sizes increase, the rotation of the blade tips resembles artificially triggered lightning, and the long air gap discharge model may underestimate the development of upward leaders. Calculations from the artificially triggered lightning model reveal improved upward leader formation when further laterally away from the downward leader within a certain distance, elucidating why multiple upward leaders are frequently observed around turbines. The striking distance and attractive radius are largely determined by the development of upward leaders. The absence of corona charge shielding at blade tips means upward leader inception is independent of downward leader velocity, emphasizing downward leaders' significant influence on turbines. Thus, the formula for estimating a wind turbine's lightning incidence requires integrating the return stroke current and velocity of the downward leader. 相似文献
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Existing studies of the spatial allocation of wind farms are typically based on turbine power generation efficiency and rarely consider the damage caused by lightning strikes. However, lightning damage seriously affects the economic performance of wind farms because of the high cost of repairing or replacing damaged blades. This paper proposes a method for the spatial optimization of multiple turbines based on lightning protection dependability. Firstly, the lightning protection efficiency of turbine blade protection systems is analyzed by combining the physical mechanisms of lightning leader progression with a conventional electro‐geometric model to develop an electro‐geometric model of turbine blades (EGMTB). Then, the optimized spatial allocation of multiple turbines in a wind farm is investigated using the EGMTB. The results are illustrated from an example wind farm with 1.5 MW turbines, which shows that the optimal spacing between two turbines perpendicular to the prevailing wind direction L⊥ is 4R‐6R, where R is the length of a turbine blade. This spacing is shown to effectively shield turbine blades from lightning damage over a wide range of lightning currents (>26‐60 kA). Note that, the suggested L⊥ will be smaller considering the influence of lightning polarity as it takes more difficulty developing upward leader (UL) in the condition of positive lightning striking. Experiments verify the effectiveness and correctness of this method. 相似文献
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With the increasing demand for wind energy, it is important to be able to understand and predict the available wind resources. To that end, the present wind tunnel study addresses the flow in the induction and entrance region of wind farms through particle image velocimetry, with focus on differences between actuator disks and two-bladed rotating wind turbine models. Both staggered and aligned farm layouts are examined for three different incoming wind directions. For each layout, 69 disks or turbines are used, and the field of view ranges from 12 rotor diameters upstream of the farms to 8 diameters downstream of the first row. The results show that the induction, or blockage effect, is higher for the disks, even though the thrust (or drag) coefficient is the same. In contrast, the wake is stronger downstream of the turbines. The orientation and layout of the farm do not have a major impact on the results. Modal decomposition of the flow shows that the flow structure similarity between the disk and turbines improves downstream of the second row of wake generating objects, indicating that the substitution of wind turbines by actuator disks is more appropriate for wind farms than for the investigation of single wakes. 相似文献
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When the installed capacity of wind power becomes high, the power generated by wind farms can no longer simply be that dictated by the wind speed. With sufficiently high penetration, it will be necessary for wind farms to provide assistance with supply‐demand matching. The work presented here introduces a wind farm controller that regulates the power generated by the wind farm to match the grid requirements by causing the power generated by each turbine to be adjusted. Further, benefits include fast response to reach the wind farm power demanded, flexibility, little fluctuation in the wind farm power output and provision of synthetic inertia. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Lightning strikes are a major threat to the secure operation of wind turbines. When lightning strikes a wind turbine, the lightning current flows through the blade and the tower and then the induced overvoltage will damage sensors and signal cables. In this study, a comprehensive transient surge impedance model of a wind turbine was built to analyze the causes of the overvoltage in the signal cable. The model that studies the overvoltage caused by both capacitive coupling and electromagnetic induction included the blade, nacelle, tower, signal cable, power cable, and grounding system using π networks. The influences of the cable shielding layer, soil resistivity, and lightning current waveform on the overvoltage were also analyzed. Then, 2 overvoltage suppression measures, ie, grounding at 2 ends of the outer shielding layer and installation of a surge protective device, were tested. Results show that a signal cable with double shielding layers reduced the overvoltage in the signal cable, and higher soil resistivity resulted in increased voltage on the tower base. In addition, the peak and the front time of the lightning current significantly influenced the overvoltage on the tower and the cable. The effectiveness of the 2 suppression measures was also verified. The calculation results will provide guidance for a reasonable lightning protection design. 相似文献
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为同一地区多个风电场集约化配置大规模储能电站可减小总储能规模从而降低成本,对此提出一种计及多风电场相关特性的集中式储能电站容量优化配置方法。首先计及多风电场实际和预测出力数据相关特性,建立联合分布藤Copula模型;其次利用降维场景生成方法生成海量多风电场联合出力场景,聚类选取典型场景;然后将典型场景序列导入储能系统约束模型,计及跟踪计划处理惩罚和波动越限惩罚,对储能电站容量进行优化配置;最后以华中某地相邻两风电场实测数据进行算例分析,实现多风电场的集中式储能定容。结果表明该方法在兼顾电网要求的同时,能优化储能电站总容量,提升多风电场和集中式储能电站的总体经济性。 相似文献
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In this paper, we consider the problem of reducing the radar cross section of a wind turbine blade through the application of radar absorbing material (RAM). One problem encountered by these techniques is the integration of the RAM solution with the existing lightning protection system, which is mandatory requirement to protect the blade when in operation. A common form of lightning protection is the use of conducting lightning receptors on the surface of the blade. To ensure the protection system is effective, a clearance area around the receptor may be required before any RAM treatment is applied. The size of the clearance area and the number of lightning receptors therefore potentially reduce the effectiveness of the RAM treatment. Design guidelines are given in this paper for a generic 40 m blade geometry. Some modelling results of the radar cross section and Doppler signature from a RAM treated blade are presented, and a comment is also made on the importance the blade edges have in reducing radar effects. ©2013 The Authors. Wind Energy published by John Wiley & Sons, Ltd. 相似文献
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Wind measurements were performed with the UTD mobile LiDAR station for an onshore wind farm located in Texas with the aim of characterizing evolution of wind‐turbine wakes for different hub‐height wind speeds and regimes of the static atmospheric stability. The wind velocity field was measured by means of a scanning Doppler wind LiDAR, while atmospheric boundary layer and turbine parameters were monitored through a met‐tower and SCADA, respectively. The wake measurements are clustered and their ensemble statistics retrieved as functions of the hub‐height wind speed and the atmospheric stability regime, which is characterized either with the Bulk Richardson number or wind turbulence intensity at hub height. The cluster analysis of the LiDAR measurements has singled out that the turbine thrust coefficient is the main parameter driving the variability of the velocity deficit in the near wake. In contrast, atmospheric stability has negligible influence on the near‐wake velocity field, while it affects noticeably the far‐wake evolution and recovery. A secondary effect on wake‐recovery rate is observed as a function of the rotor thrust coefficient. For higher thrust coefficients, the enhanced wake‐generated turbulence fosters wake recovery. A semi‐empirical model is formulated to predict the maximum wake velocity deficit as a function of the downstream distance using the rotor thrust coefficient and the incoming turbulence intensity at hub height as input. The cluster analysis of the LiDAR measurements and the ensemble statistics calculated through the Barnes scheme have enabled to generate a valuable dataset for development and assessment of wind farm models. 相似文献
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风电机组的性能评估方法具有多样性及复杂性的特点,基于风电场SCADA系统中采集的大量风电机组运行数据,对风电机组转矩控制的性能评估方法进行了研究。在深入分析风电机组中发电机转速与发电机转矩关系的基础上,提出了风电机组在最佳风能利用系数C(p(max))跟踪区内的转矩优化控制的性能评估方法。通过筛选有效数据,拟合计算出风电机组的实际运行转矩增益系数;再通过与理论最优转矩增益系数进行对比,找出风能捕获能力较弱的风电机组,进而采取措施提高其发电量。通过软件仿真及案例分析表明,该方法在不增加设备及成本的情况下,可有效识别因转矩控制的性能差而影响发电量的风电机组,以便及时进行控制策略调校,维护风电场的利益。 相似文献
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考虑风电场接入电网时,传统方向元件在短路故障发生时易受到风电场内部电力电子器件动态特性的干扰影响,导致频率特性偏移,系统参数不稳定和弱馈性等问题,使继电保护装置不能及时或正确判断故障发生区域。针对上述问题,首先对含有风电场的故障附加网络进行分析,寻找故障发生后纵联保护安装处各测量点电气量之间的关联性,确定其故障逻辑关系。其次通过对常用的相模变换解耦方式进行分析,选择一个合理的方法代入相关性表达式,根据相关系数值完成故障区域判定。最后利用PSCAD/EMTDC搭建双馈风电场并网模型,设置各种不同的故障类型和场景,并利用Matlab进行保护算法验证,检验故障区域判断结果,验证所提保护方法的正确性与合理性,并且仿真结果表明该方法具有较高的可靠性。 相似文献
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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。 相似文献
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This paper presents a contribution to wind farm ouput power estimation. The calculation for a single wind turbine involves the use of the power coefficient or, more directly, the power curve data sheet. Thus, if the wind speed value is given, a simple calculation or search in the data sheet will provide the generated power as a result. However, a wind farm generally comprises more than one wind turbine, which means the estimation of power generated by the wind farm as a function of the wind speed is a more complex process that depends on several factors, including the important issue of wind direction. While the concept of a wind turbine power curve for a single wind turbine is clear, it is more subject to discussion when applied to a whole wind farm. This paper provides a simplified method for the estimation of wind farm power, based on the use of an equivalent wake effect coefficient. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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工频过电压是影响220kV海上风电场混合海缆输电线路安全的重要因素。以我国东部某典型的220kV近海风电场输电系统为例,基于ATP-EMTP对海上风电场系统及其送出的混合海缆输电线路进行建模,对混合线路的空载长线电容效应工频过电压进行了理论分析,分别仿真计算了不同海缆类型、海缆长度、海缆架空线比例下空载容升及单相接地三相断开的工频过电压。结果表明,同等截面下,三芯海缆时工频过电压整体较单芯海缆严重;随着海缆占比增大,混合海缆输电线路由于容升效应导致的工频过电压先增大后减小;对于装机容量为200MW的海上风电场,当海缆长度超过27km时,工频过电压将超过规定的1.3p.u.。 相似文献
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This article provides an overview and analysis of different wake‐modelling methods which may be used as prediction and design tools for both wind turbines and wind farms. We also survey the available data concerning the measurement of wind magnitudes in both single wakes and wind farms, and of loading effects on wind turbines under single‐ and multiple‐wake conditions. The relative merits of existing wake and wind farm models and their ability to reproduce experimental results are discussed. Conclusions are provided concerning the usefulness of the different modelling approaches examined, and difficult issues which have not yet been satisfactorily treated and which require further research are discussed. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
