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针对风电场中各风电机组风速之间存在的复杂时空相关性问题,提出一种基于混合Copula优化算法的风电场风速预测方法。该方法首先分析单一Copula函数拟合优度检验,选取合适Copula函数进行组合;其次,构建混合Copula函数模型对风电场内多风电机组风速相关性进行分析;最后应用最大期望(EM)算法求解模型相关系数并完成风速预测。结合优化算法,改进Copula函数能很好地解决风速相关性问题,为获取准确风速预测值奠定基础。以中国某地区风电场风电机组实测风速数据为例对所提方法进行验证,实验结果表明该模型可在准确分析风速相关性的基础上提高风速预测准确性。 相似文献
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由于风机的无功耗变,电网电压稳定性随着风力渗透的增加而降低.针对风电场接入的配电网系统无功优化调度问题,本文提出了一种基于ADMM算法的两级无功优化调度方法.与现有的无功优化控制方法相比,该方法采用两阶段优化结构实现分布式无功优化调度.此外,在分区概念下,不需要一致性协议来解决优化问题.该方法在控制设计中也考虑了各个风... 相似文献
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针对传统设计洪水频率分析采用单变量方法且不考虑变量间相关关系的问题,以江西省柘林水库坝址洪水为研究对象,采用Frank Copula函数构建洪峰与5d洪量的二元联合分布,并引入联合重现期的概念。结果表明,柘林水库坝址洪水主要受洪峰和洪量控制,峰量间存在良好的相关性;两变量方法推求的峰量联合设计值均大于单变量方法,各特征量的重现期均高于设计标准。可见Copula函数拟合度较高,计算所得频率设计值更符合洪水事件的内在规律以及工程实际要求,且同时可得不同情况下的峰量设计值组合,在水文领域具有广阔的应用前景。 相似文献
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为综合描述漳河上游干旱事件,选取月降水数据计算标准化降水指数,应用游程理论识别干旱历时和干旱强度两种干旱特征变量,并采用Copula函数构建两种干旱特征变量间的联合分布,探究干旱特征的时空分布。结果表明,漳河上游2001~2020年发生频率最高干旱事件为3个月历时干旱,干旱强度范围为2.24~4.92;干旱历时和干旱强度间存在强正相关性,Frank Copula函数为二者最优联合分布;干旱特征联合重现期范围为18.56~23.94年,在漳河上游西北和东南流域表现2个干旱高风险区,同现重现期范围为22.25~31.94年,在西北、东北和东南流域表现3个干旱高风险区。联合分布综合分析了干旱事件,可为全面评估旱情提供科学参考。 相似文献
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《International Journal of Hydrogen Energy》2020,45(17):10280-10291
Hydrogen and photovoltaic (PV) are two typical new energies, which are important to sustainable development. Introducing hydrogen or PV into smart grid as distributed generation (DG) becomes a promising approach. These kinds of power generations will help the grid gather more energy and introduce new chances of grid management. In this paper, we will introduce an application of hydrogen and PV in reactive power control. PV is used for hydrogen harvest, and PV is variable and dependent on weather conditions compared with a conventional generator that produces a stable output. Photovoltaic hydrogen fuel cell (PV--FC) is introduced as DG, which connects to the grid. Adding hydrogen-based DG would help improve the quality of supply power. A genetic algorithm for DG site selection supporting DG cost optimization is proposed. Reactive power optimization (RPO) is an important function in planning for the future and daily operations of the smart grid system. Implementation of reactive power optimization based on the historical solution matching is also proposed, it considers the PV--FC features and grid historical data, which uses Cosine distance for similarity measurement. The proposed RPO algorithm has a great advantage in calculation speed compared with traditional algorithms. The historical load data with the highest similarity are extracted, and its historical RPO scheme is applied to simulate the current RPO scheme. Results show that this method could help to find out an RPO solution effectively. The proposed solution would provide processing purposes for power company information data and further explore the supporting role of information resources in grid operations, which has broad social benefits. 相似文献
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遗传算法在电力系统无功优化中的应用综述 总被引:1,自引:0,他引:1
遗传算法是近10年来发展的基于自然选择规律的一种优化方法,算法能成功的解决无功变量中的离散问题,避免常规数学优化方法的局部最优现象。本文阐述了简单遗传算法以及遗传算法与其它算法相结合的算法在电力系统无功优化中的应用和今后的发展方向。 相似文献
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Wind parks always produce diverse percentages of their nominal power at the same time, leading to a concern about correlation between wind speeds. The assessments of wind speed correlation have been particularly focused on probabilistic modeling of aleatory uncertainty. However, poor historical data, imprecise parameter estimation and incomplete knowledge of wind speeds lead to another type of uncertainty, possibilistic uncertainty, which requires an explicit analysis. Therefore, a fuzzy copula model is firstly proposed to express the possibilistic uncertainty of wind speed correlation. The advantage of the proposed model is that the copula parameters can be interval numbers, triangular or trapezoidal fuzzy numbers based on the wind speed data and subjective judgment of decision makers. For estimating copula parameters, a complete decision rule and interval estimation method is developed based on cumulative probability and probability distributions of correlated wind speeds. The effectiveness of the proposed model is validated by the application in wind curtailment evaluation while a method is developed to evaluate and quantify wind curtailment in a hybrid power system involving different types of generation. The results demonstrate that the proposed model and method are capable of describing the possibilistic uncertainty and evaluating its effect on wind curtailment. Compared with previous research, the proposed model develops a new universal parameter estimation method and selection rule to provide more interval results, by calculating the membership function of copula parameters and wind curtailment. System planners and operators can apply the fuzzy results to various topics like reserve capacity evaluation or real-time dispatch depending on their level of risk tolerance. 相似文献
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为了能够准确地描述分布式电源出力的不确定性和负荷波动性,延长控制设备使用寿命,降损节能,提出了一种含分布式电源的基于区间仿射算术的电网动态无功优化方法。用区间数表示每一时段负荷、分布式电源出力的波动情况,进行了基于区间仿射算术的潮流计算。以全天24个时段总网损最小和全网所有节点电压越限惩罚最小构成目标函数,增加了控制变量连续时段动作约束。将区间仿射算术和自适应粒子群(算法结合,进行静态无功优化,形成控制设备预动作表,并进行动态调整。最后,通过改进的IEEE 30节点系统进行案例分析,仿真结果表明了该方法的有效性。 相似文献
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多微电网互联结构可实现多个微电网间的能量协调,并形成能源互补优势。文章针对多微电网中各分布式电源在天气变化影响下产生的出力不确定性问题,以提高微电网互联系统电压稳定性为目标,研究基于微电网互联结构的微电网间功率协调控制方法。研究单个微电网内分布式电源出力波动特性及其与微电网互联系统、配电网系统之间的能量协调与功率支撑需求特性,建立基于功率平衡控制的微电网间互联控制策略;研究微电网互联系统内各微电网控制系统平衡计算,建立微电网互联系统与配电网间能量交换的控制模型与控制策略。以三机九节点拓扑模型建立微电网互联系统及接入网协调控制模型和算法进行验证,仿真结果表明,文章所提出的微电网协调优化控制方法能够有效减小微电网波动以及对配电网的影响。 相似文献
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