电力在不同的时间范围和法规上在各个市场上进行交易。由于更高的可再生能源渗透,短期交易变得越来越重要。在德国,盘中电价通常以独特的小时模式围绕EPEX现货市场的白天价格波动。这项工作提出了一种概率建模方法,该方法对日前合同的盘中价格差异进行了建模。该模型通过将每天的每日价格间隔的四个15分钟的间隔视为四维的关节分布,从而捕获了新兴的小时模式。使用归一化流量,即结合条件多元密度估计和概率回归的深层生成模型,从而学习了最终的多元价格差异分布。将归一化流程与选择的历史数据,高斯副群和高斯回归模型进行了比较。在不同的模型中,归一化流量最准确地识别趋势,并且预测间隔最窄。值得注意的是,归一化流是唯一识别稀有价格峰的方法。最后,这项工作讨论了不同外部影响因素的影响,并发现个人大多数因素都可以忽略不计。只有价格差异实现的直接历史和所有投入因素的组合才能显着改善预测。
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我们提出了一种专门的方案生成方法,该方法利用预测信息来生成用于日期调度问题的方案。特别是,我们使用归一化的流量来通过从有条件的分布进行采样,该分布使用风速预测来定制方案到特定的一天。我们将生成的方案应用于风能生产者的随机日期招标问题中,并分析该方案是否产生有利可图的决策。与高斯Copulas和Wasserstein基因的对抗网络相比,正常化的流程成功地缩小了每日趋势周围的各种场景范围,同时保持了各种可能的实现。在随机日间招标问题中,与历史场景的无条件选择相比,所有方法的条件情况都会导致更稳定的盈利结果。归一化流量始终获得最高利润,即使对于小型场景。
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基于神经网络的学习,从光伏(PV)和风中的来源以及负载需求的来源的不可转型可再生发电的分布的学习最近得到了注意力。由于通过直接对数似然最大化训练,归一化流量密度模型特别适用于此任务。然而,从图像生成领域的研究表明,标准归一化流量只能学习歧管分布的涂抹版本。以前的作品在规范化基于流的方案生成的情况下,不要解决这个问题,并且掩弹的分布导致噪声时间序列的采样。在本文中,我们利用了主成分分析(PCA)的等距,从而建立了较低尺寸空间中的标准化流量,同时保持直接和计算有效的似然最大化。我们在2013年至2015年培训PV和风力发电的数据以及德国的负载需求的所得到的主要成分流量(PCF)。本研究结果表明,PCF保留了原始分布的关键特征,如作为时间序列的概率密度和频率行为。然而,PCF的应用不限于可再生能力,而是扩展到任何数据集,时间序列或其他方式,可以使用PCA有效地减少。
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现代能源系统的设计和运营受到时间依赖性和不确定参数的严重影响,例如可再生发电,负荷需求和电价。这些通常由称为场景的一组离散的实现表示。一种流行的情景生成方法使用允许场景生成的深生成模型(DGM),而无需现有的数据分布。但是,生成方案的验证很困难,目前缺乏对适当的验证方法的全面讨论。为了开始讨论,我们对能源情景生成文献中当前使用的验证方法的关键评估。特别是,我们评估基于概率密度,自动相关和功率谱密度的验证方法。此外,我们建议使用多重术后波动分析(MFDFA)作为峰,爆发和平稳等非琐碎功能的额外验证方法。作为代表性的例子,我们培养了两种可再生发电时间序列(2013年到2015年德国的Photovolataic Antialsion(VAES),以及来自德国的光伏和风的变分自动化器(VAES)和一天电费时间序列在2017年至2019年形成欧洲能源交换。我们将四种验证方法应用于历史和生成的数据,并讨论验证结果的解释以及验证方法的常见错误,陷阱和局限性。我们的评估表明,没有单一方法足够特征,但理想的验证应该包括多种方法,并且在短时间内的情况下仔细解释。
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电力行业正在大力实施智能网格技术,以提高可靠性,可用性,安全性和效率。该实施需要技术进步,标准和法规的发展以及测试和计划。智能电网载荷预测和管理对于降低需求波动和改善连接发电机,分销商和零售商的市场机制至关重要。在政策实施或外部干预措施中,有必要分析其对电力需求的影响的不确定性,以使系统对需求的波动更加准确。本文分析了外部干预的不确定性对电力需求的影响。它实现了一种结合概率和全局预测模型的框架,使用深度学习方法来估计干预措施的因果影响分布。通过预测受影响实例的反事实分布结果,然后将其与实际结果进行对比来评估因果效应。我们将COVID-19锁定对能源使用的影响视为评估这种干预对电力需求分布的不均匀影响的案例研究。我们可以证明,在澳大利亚和某些欧洲国家的最初封锁期间,槽通常比峰值更大的下降,而平均值几乎不受影响。
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我们研究了欧洲排放津贴(EUA)的价格,从而分析了它们对相关能源市场的不确定性和依赖性。我们提出了一个概率的多元条件时间序列模型,该模型利用数据的关键特征。在广泛的滚动窗口预测研究中评估了提议模型和各种竞争模型的预测性能,涵盖了将近两年的样本外。因此,我们预测了30步。多元概率预测的准确性由能量评分评估。鉴于俄罗斯对乌克兰的入侵,我们还讨论了着重于波动性溢出和随时间变化的相关性的发现。
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我们提出了一种利用分布人工神经网络的概率电价预测(EPF)的新方法。EPF的新型网络结构基于包含概率层的正则分布多层感知器(DMLP)。使用TensorFlow概率框架,神经网络的输出被定义为一个分布,是正常或可能偏斜且重尾的Johnson的SU(JSU)。在预测研究中,将该方法与最新基准进行了比较。该研究包括预测,涉及德国市场的日常电价。结果显示了对电价建模时较高时刻的重要性的证据。
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PV power forecasting models are predominantly based on machine learning algorithms which do not provide any insight into or explanation about their predictions (black boxes). Therefore, their direct implementation in environments where transparency is required, and the trust associated with their predictions may be questioned. To this end, we propose a two stage probabilistic forecasting framework able to generate highly accurate, reliable, and sharp forecasts yet offering full transparency on both the point forecasts and the prediction intervals (PIs). In the first stage, we exploit natural gradient boosting (NGBoost) for yielding probabilistic forecasts, while in the second stage, we calculate the Shapley additive explanation (SHAP) values in order to fully comprehend why a prediction was made. To highlight the performance and the applicability of the proposed framework, real data from two PV parks located in Southern Germany are employed. Comparative results with two state-of-the-art algorithms, namely Gaussian process and lower upper bound estimation, manifest a significant increase in the point forecast accuracy and in the overall probabilistic performance. Most importantly, a detailed analysis of the model's complex nonlinear relationships and interaction effects between the various features is presented. This allows interpreting the model, identifying some learned physical properties, explaining individual predictions, reducing the computational requirements for the training without jeopardizing the model accuracy, detecting possible bugs, and gaining trust in the model. Finally, we conclude that the model was able to develop complex nonlinear relationships which follow known physical properties as well as human logic and intuition.
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Electricity prices in liberalized markets are determined by the supply and demand for electric power, which are in turn driven by various external influences that vary strongly in time. In perfect competition, the merit order principle describes that dispatchable power plants enter the market in the order of their marginal costs to meet the residual load, i.e. the difference of load and renewable generation. Many market models implement this principle to predict electricity prices but typically require certain assumptions and simplifications. In this article, we present an explainable machine learning model for the prices on the German day-ahead market, which substantially outperforms a benchmark model based on the merit order principle. Our model is designed for the ex-post analysis of prices and thus builds on various external features. Using Shapley Additive exPlanation (SHAP) values, we can disentangle the role of the different features and quantify their importance from empiric data. Load, wind and solar generation are most important, as expected, but wind power appears to affect prices stronger than solar power does. Fuel prices also rank highly and show nontrivial dependencies, including strong interactions with other features revealed by a SHAP interaction analysis. Large generation ramps are correlated with high prices, again with strong feature interactions, due to the limited flexibility of nuclear and lignite plants. Our results further contribute to model development by providing quantitative insights directly from data.
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电价是影响所有市场参与者决策的关键因素。准确的电价预测非常重要,并且由于各种因素,电价高度挥发性,电价也非常具有挑战性。本文提出了一项综合的长期经常性卷积网络(ILRCN)模型,以预测考虑到市场价格的大多数贡献属性的电力价格。所提出的ILRCN模型将卷积神经网络和长短期记忆(LSTM)算法的功能与所提出的新颖的条件纠错项相结合。组合的ILRCN模型可以识别输入数据内的线性和非线性行为。我们使用鄂尔顿批发市场价格数据以及负载型材,温度和其他因素来说明所提出的模型。使用平均绝对误差和准确性等性能/评估度量来验证所提出的ILRCN电价预测模型的性能。案例研究表明,与支持向量机(SVM)模型,完全连接的神经网络模型,LSTM模型和LRCN模型,所提出的ILRCN模型在电价预测中是准确和有效的电力价格预测。
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时间变化数量的估计是医疗保健和金融等领域决策的基本组成部分。但是,此类估计值的实际实用性受到它们量化预测不确定性的准确程度的限制。在这项工作中,我们解决了估计高维多元时间序列的联合预测分布的问题。我们提出了一种基于变压器体系结构的多功能方法,该方法使用基于注意力的解码器估算关节分布,该解码器可被学会模仿非参数Copulas的性质。最终的模型具有多种理想的属性:它可以扩展到数百个时间序列,支持预测和插值,可以处理不规则和不均匀的采样数据,并且可以在训练过程中无缝地适应丢失的数据。我们从经验上证明了这些属性,并表明我们的模型在多个现实世界数据集上产生了最新的预测。
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一些现实世界决策问题需要立即对多个步骤进行概率预测。然而,概率预测方法可能无法捕获在长时间视野中存在的基础时间序列中的相关性,因为累积累积。一个这样的应用是在网格环境中不确定性下的资源调度,这需要预测电力需求,这是自然嘈杂的,但通常是循环的。在本文中,我们介绍了条件近似标准化流量(CANF),以便在长时间视野中存在相关性时进行概率的多步时间序列预测。我们首先展示了我们对估计玩具分布密度的方法的功效,发现CANF与高斯混合模型相比通过三分之一提高了KL发散,同时仍可用于显式调理。然后,我们使用公开的家用电力消耗数据集来展示CANF在联合概率多步预测上的有效性。经验结果表明,条件近似标准化流动在多步骤预测精度方面优于其他方法,并导致高达10倍的调度决策。我们的实现可在https://github.com/sisl/jointdemandforecast中获得。
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中期地平线(几个月到一年)功耗预测是能源部门的主要挑战,特别是当考虑概率预测时。我们提出了一种新的建模方法,该方法包含趋势,季节性和天气条件,作为具有自回归特征的浅神经网络中的解析变量。我们在将其应用于新英格兰的日常电力消耗的一年试验集上获得优异的效果预测。一方面已经验证了实现的电力消耗概率预测的质量,将结果与其他标准进行比较密度预测模型,另一方面,考虑在能量扇区中经常使用的措施,作为弹球损失和CI逆退。
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基于预测方法的深度学习已成为时间序列预测或预测的许多应用中的首选方法,通常通常优于其他方法。因此,在过去的几年中,这些方法现在在大规模的工业预测应用中无处不在,并且一直在预测竞赛(例如M4和M5)中排名最佳。这种实践上的成功进一步提高了学术兴趣,以理解和改善深厚的预测方法。在本文中,我们提供了该领域的介绍和概述:我们为深入预测的重要构建块提出了一定深度的深入预测;随后,我们使用这些构建块,调查了最近的深度预测文献的广度。
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随着可再生能源的延伸升幅,盘中电市场在交易商和电力公用事业中录得不断增长的普及,以应对能源供应的诱导波动。通过其短途交易地平线和持续的性质,盘中市场提供了调整日前市场的交易决策的能力,或者在短期通知中降低交易风险。通过根据当前预测修改其提供的能力,可再生能源的生产者利用盘中市场降低预测风险。然而,由于电网必须保持稳定,电力仅部分可存储,因此市场动态很复杂。因此,需要在盘区市场中运营的强大和智能交易策略。在这项工作中,我们提出了一种基于深度加强学习(DRL)算法的新型自主交易方法作为可能的解决方案。为此目的,我们将盘区贸易塑造为马尔可夫决策问题(MDP),并采用近端策略优化(PPO)算法作为我们的DRL方法。介绍了一种模拟框架,使得连续盘整价格的分辨率提供一分钟步骤。从风园运营商的角度来看,我们在案例研究中测试我们的框架。我们在普通贸易信息旁边包括价格和风险预测。在2018年德国盘区交易结果的测试场景中,我们能够以至少45.24%的改进优于多个基线,显示DRL算法的优势。但是,我们还讨论了DRL代理的局限性和增强功能,以便在未来的工作中提高性能。
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We propose Multivariate Quantile Function Forecaster (MQF$^2$), a global probabilistic forecasting method constructed using a multivariate quantile function and investigate its application to multi-horizon forecasting. Prior approaches are either autoregressive, implicitly capturing the dependency structure across time but exhibiting error accumulation with increasing forecast horizons, or multi-horizon sequence-to-sequence models, which do not exhibit error accumulation, but also do typically not model the dependency structure across time steps. MQF$^2$ combines the benefits of both approaches, by directly making predictions in the form of a multivariate quantile function, defined as the gradient of a convex function which we parametrize using input-convex neural networks. By design, the quantile function is monotone with respect to the input quantile levels and hence avoids quantile crossing. We provide two options to train MQF$^2$: with energy score or with maximum likelihood. Experimental results on real-world and synthetic datasets show that our model has comparable performance with state-of-the-art methods in terms of single time step metrics while capturing the time dependency structure.
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Algorithms that involve both forecasting and optimization are at the core of solutions to many difficult real-world problems, such as in supply chains (inventory optimization), traffic, and in the transition towards carbon-free energy generation in battery/load/production scheduling in sustainable energy systems. Typically, in these scenarios we want to solve an optimization problem that depends on unknown future values, which therefore need to be forecast. As both forecasting and optimization are difficult problems in their own right, relatively few research has been done in this area. This paper presents the findings of the ``IEEE-CIS Technical Challenge on Predict+Optimize for Renewable Energy Scheduling," held in 2021. We present a comparison and evaluation of the seven highest-ranked solutions in the competition, to provide researchers with a benchmark problem and to establish the state of the art for this benchmark, with the aim to foster and facilitate research in this area. The competition used data from the Monash Microgrid, as well as weather data and energy market data. It then focused on two main challenges: forecasting renewable energy production and demand, and obtaining an optimal schedule for the activities (lectures) and on-site batteries that lead to the lowest cost of energy. The most accurate forecasts were obtained by gradient-boosted tree and random forest models, and optimization was mostly performed using mixed integer linear and quadratic programming. The winning method predicted different scenarios and optimized over all scenarios jointly using a sample average approximation method.
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对极端事件的风险评估需要准确估算超出历史观察范围的高分位数。当风险取决于观察到的预测因子的值时,回归技术用于在预测器空间中插值。我们提出的EQRN模型将来自神经网络和极值理论的工具结合到能够在存在复杂预测依赖性的情况下外推的方法中。神经网络自然可以在数据中融合其他结构。我们开发了EQRN的经常性版本,该版本能够在时间序列中捕获复杂的顺序依赖性。我们将这种方法应用于瑞士AARE集水区中洪水风险的预测。它利用从时空和时间上的多个协变量中利用信息,以提供对回报水平和超出概率的一日预测。该输出从传统的极值分析中补充了静态返回水平,并且预测能够适应不断变化的气候中经历的分配变化。我们的模型可以帮助当局更有效地管理洪水,并通过预警系统最大程度地减少其灾难性影响。
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在本文中,我们呈现SSDNet,这是一个新的时间序列预测的深层学习方法。SSDNet将变压器架构与状态空间模型相结合,提供概率和可解释的预测,包括趋势和季节性成分以及前一步对预测很重要。变压器架构用于学习时间模式并直接有效地估计状态空间模型的参数,而无需对卡尔曼滤波器的需要。我们全面评估了SSDNET在五个数据集上的性能,显示SSDNet是一种有效的方法,可在准确性和速度,优于最先进的深度学习和统计方法方面是一种有效的方法,能够提供有意义的趋势和季节性组件。
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Wind power forecasting helps with the planning for the power systems by contributing to having a higher level of certainty in decision-making. Due to the randomness inherent to meteorological events (e.g., wind speeds), making highly accurate long-term predictions for wind power can be extremely difficult. One approach to remedy this challenge is to utilize weather information from multiple points across a geographical grid to obtain a holistic view of the wind patterns, along with temporal information from the previous power outputs of the wind farms. Our proposed CNN-RNN architecture combines convolutional neural networks (CNNs) and recurrent neural networks (RNNs) to extract spatial and temporal information from multi-dimensional input data to make day-ahead predictions. In this regard, our method incorporates an ultra-wide learning view, combining data from multiple numerical weather prediction models, wind farms, and geographical locations. Additionally, we experiment with global forecasting approaches to understand the impact of training the same model over the datasets obtained from multiple different wind farms, and we employ a method where spatial information extracted from convolutional layers is passed to a tree ensemble (e.g., Light Gradient Boosting Machine (LGBM)) instead of fully connected layers. The results show that our proposed CNN-RNN architecture outperforms other models such as LGBM, Extra Tree regressor and linear regression when trained globally, but fails to replicate such performance when trained individually on each farm. We also observe that passing the spatial information from CNN to LGBM improves its performance, providing further evidence of CNN's spatial feature extraction capabilities.
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