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目前风功率预测多为风功率期望的点预测,且以采样间隔较大的功率序列作为建模序列,这样会降低预测模型对风功率时序特征模拟的准确度和可信度。文中基于小采样间隔风功率序列,提出ARMAX-GARCH风功率预测模型。通过构造风功率新息序列,结合小时平均风功率序列,建立ARMAX点预测模型,采用BIC最小信息准则和相关性分析实现模型定阶和外生变量选择;采用GARCH模型模拟残差的波动特性实现区间预测。以海岛微电网实测风功率数据为例,进行提前1 h风功率预测。结果表明,与持续法、ARMA和RBF神经网络相比,该预测模型能显著提高风功率期望的点预测精度并具有较好的区间预测效果。 相似文献
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介绍了基于可靠性指标LOLP的风电场容量可信度计算方法,同时给出了用于风电场可靠性计算的两种模型———发电机模型和负的负荷模型。利用不同的模型,结合实际算例,得出了一系列的计算结果,并对可能影响风电场容量可信度的一些相关因素作了灵敏度分析。 相似文献
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为提高短期风功率预测精度和预测的可控性,提出一种基于能量差优化变分模态分解和布谷鸟优化组合神经网络的短期风功率预测模型。采用能量差优化变分模态分解(EVMD)的模态数,将EVMD用于短期风功率分解,基于EVMD分解序列的不同模态特点,对非线性序列采用布谷鸟优化反向传播神经网络(CS-BPNN),对平稳序列采用自回归滑动平均模型(ARMA),并重构加权得到点预测值,并基于EVMD分解所丢失的序列信息构建核密度估计,在点预测模型的基础上,进行风功率的区间预测。将所提预测方法用于澳大利亚风电场的实际算例,实验结果表明,该方法可提高短期风功率预测的准确性。 相似文献
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风功率预测在不同应用场景中发挥着越来越重要的作用,从时间尺度上可分为超短期、短期和中长期的风功率预测。基于短期风功率预测对训练时间和预测精度均有较高要求,提出了一种利用共轭梯度(cconjugate gradient,CG)法优化核极限学习机(kernel extreme learning machine,KELM)的方法,即利用共轭梯度核极限学习机(CGKELM)方法来预测风功率,在保证预测精度的前提下,进一步缩短KELM的训练时间。通过利用某风电场的实测数据进行仿真,以均方根误差和相对标准差作为评价指标,将仿真结果分别与反向传播(BP)神经网络、最小二乘支持向量机(LSSVM)和其他KELM方法得到的结果进行比较。研究结果表明:在短期风功率预测方面,CGKELM训练时间比其他方法短,且参数设置简单。该结果证明了CGKELM的有效性,对风电项目的投资决策具有一定的参考价值。 相似文献
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在风功率预测误差建模应用中,无偏交叉验证(UCV)和经验法则(ROT)是两种常用的非参数方法。然而,由于风功率预测误差中存在的尖峰厚尾,以及局部小样本特征,直接使用这两种方法会产生较大的泛化误差。为了使UCV和ROT在应用中发挥更好的作用,文章提出了一种基于光滑自助法的核密度估计方法。该方法利用了光滑自助法在分位数推断上的优势,通过修改平均积分平方误差(MISE)指标函数,实现了对基本估计方法的校正。该方法本质上是一种装袋方法,可以与任何基本的核密度方法结合使用。在实例仿真中,得到了SBUCV方法和SBROT方法的运行结果,并与UCV和ROT方法的结果进行了对比。仿真结果表明了该方法的有效性。 相似文献
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基于武汉地区分布式光伏电站大量实测数据,运用广义高斯分布和有限学生t混合模型等多种概率模型对不同时间尺度下光伏功率波动特性建模,发现在10~15min时间尺度下广义高斯分布最适用于描述分布式光伏功率变化的概率分布,而在30~60min时间尺度下高斯混合模型拟合效果最好。在此基础上,建立了逐时光伏出力波动与辐射量波动模型,用于定量分析光伏电站能量输出波动,可有效降低光伏功率波动随机性和不确定性对电力系统运行造成的影响,有利于提高光伏并网渗透率。 相似文献
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Understanding the effects of large‐scale wind power generation on the electric power system is growing in importance as the amount of installed generation increases. In addition to wind speed, the direction of the wind is important when considering wind farms, as the aggregate generation of the farm depends on the direction of the wind. This paper introduces the wrapped Gaussian vector autoregressive process for the statistical modeling of wind directions in multiple locations. The model is estimated using measured wind direction data from Finland. The presented methodology can be used to model new locations without wind direction measurements. This capability is tested with two locations that were left out of the estimation procedure. Through long‐term Monte Carlo simulations, the methodology is used to analyze two large‐scale wind power scenarios with different geographical distributions of installed generation. Wind generation data are simulated for each wind farm using wind direction and wind speed simulations and technical wind farm information. It is shown that, compared with only using wind speed data in simulations, the inclusion of simulated wind directions enables a more detailed analysis of the aggregate wind generation probability distribution. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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A modeling tool has been developed which can be used to analyze interaction between intermittent wind power generation and thermal power plant generation in a regional electricity grid system. The model uses a mixed integer programming (MIP) approach to determine the power plant dispatch strategy which yields the lowest systems costs. In the model, each large thermal plant is described separately, including properties such as start-up time, start-up cost and minimum load level. The model is evaluated using western Denmark as a case study.For western Denmark, it is found that the inclusion of start-up performance (i.e. start-up time and related costs) and minimum load level of the power generating units have a significant impact on the results. It is shown that the inclusion of these aspects influences the analysis of the effect of wind power variations on the production patterns of thermal units in the system. The model demonstrates how the introduction of wind power production and associated variations change the dispatch order of the large thermal power plants in the western Denmark system so that the unit with the lowest running costs no longer has the highest capacity factor. It is shown that this effect only is detected if start-up performance and minimum load level limitations are included in the optimization. It can also be concluded that start-up performance and minimum load level must be taken into account if the total system costs and emissions are not to be underestimated. The simulations show that if these aspects are disregarded, both total costs and total emissions of the power system are underestimated, with 5% in the case of western Denmark. Models such as the one developed in this work can be efficient tools to understand the effects of large-scale wind power integration in a power generation system with base load plants. 相似文献
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A.S. Barker Jr. 《Solar Energy》1986,37(1)
Low-cost digital wind speed histogram recorders were designed to survey the west coast of British Columbia. Results are presented for several shore and island locations in terms of an available power parameter. Additional short term measurements of autocorrelation and cross-correlation functions showed ten-second exponential correlation in velocity fluctuations and gave values for the root mean square fluctuation. A derivation is given of the response time of a Darrieus wind energy converter, which has implications for the sampling time of any wind speed recorder, and for the power fluctuations to be expected from such a converter. 相似文献
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Wind power forecasting for projection times of 0–48 h can have a particular value in facilitating the integration of wind power into power systems. Accurate observations of the wind speed received by wind turbines are important inputs for some of the most useful methods for making such forecasts. In particular, they are used to derive power curves relating wind speeds to wind power production. By using power curve modeling, this paper compares two types of wind speed observations typically available at wind farms: the wind speed and wind direction measurements at the nacelles of the wind turbines and those at one or more on‐site meteorological masts (met masts). For the three Australian wind farms studied in this project, the results favor the nacelle‐based observations despite the inherent interference from the nacelle and the blades and despite calibration corrections to the met mast observations. This trend was found to be stronger for wind farm sites with more complex terrain. In addition, a numerical weather prediction (NWP) system was used to show that, for the wind farms studied, smaller single time‐series forecast errors can be achieved with the average wind speed from the nacelle‐based observations. This suggests that the nacelle‐average observations are more representative of the wind behavior predicted by an NWP system than the met mast observations. Also, when using an NWP system to predict wind farm power production, it suggests the use of a wind farm power curve based on nacelle‐average observations instead of met mast observations. Further, it suggests that historical and real‐time nacelle‐average observations should be calculated for large wind farms and used in wind power forecasting. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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《全球能源互联网(英文)》2019,2(4):318-327
With the increasing proportion of wind power integration, the volatility of wind power brings huge challenges to the safe and stable operation of the electric power system. At present, the indexes commonly used to evaluate the volatility of wind power only consider its overall characteristics, such as the standard deviation of wind power, the average of power variables, etc., while ignoring the detailed volatility of wind power, that is, the features of the frequency distribution of power variables. However, how to accurately describe the detailed volatility of wind power is the key foundation to reduce its adverse influences. To address this, a quantitative method for evaluating the detailed volatility of wind power at multiple temporal-spatial scales is proposed. First, the volatility indexes which can evaluate the detailed fluctuation characteristics of wind power are presented, including the upper confidence limit, lower confidence limit and confidence interval of power variables under the certain confidence level. Then, the actual wind power data from a location in northern China is used to illustrate the application of the proposed indexes at multiple temporal (year-season-month-day) and spatial scales (wind turbine-wind turbines-wind farm-wind farms) using the calculation time windows of 10 min, 30 min, 1 h, and 4 h. Finally, the relationships between wind power forecasting accuracy and its corresponding detailed volatility are analyzed to further verify the effectiveness of the proposed indexes. The results show that the proposed volatility indexes can effectively characterize the detailed fluctuations of wind power at multiple temporal-spatial scales. It is anticipated that the results of this study will serve as an important reference for the reserve capacity planning and optimization dispatch in the electric power system which with a high proportion of renewable energy. 相似文献