4,357 research outputs found
A spliced Gamma-Generalized Pareto model for short-term extreme wind speed probabilistic forecasting
Renewable sources of energy such as wind power have become a sustainable
alternative to fossil fuel-based energy. However, the uncertainty and
fluctuation of the wind speed derived from its intermittent nature bring a
great threat to the wind power production stability, and to the wind turbines
themselves. Lately, much work has been done on developing models to forecast
average wind speed values, yet surprisingly little has focused on proposing
models to accurately forecast extreme wind speeds, which can damage the
turbines. In this work, we develop a flexible spliced Gamma-Generalized Pareto
model to forecast extreme and non-extreme wind speeds simultaneously. Our model
belongs to the class of latent Gaussian models, for which inference is
conveniently performed based on the integrated nested Laplace approximation
method. Considering a flexible additive regression structure, we propose two
models for the latent linear predictor to capture the spatio-temporal dynamics
of wind speeds. Our models are fast to fit and can describe both the bulk and
the tail of the wind speed distribution while producing short-term extreme and
non-extreme wind speed probabilistic forecasts.Comment: 25 page
Wind Power Forecasting Methods Based on Deep Learning: A Survey
Accurate wind power forecasting in wind farm can effectively reduce the enormous impact on grid operation safety when high permeability intermittent power supply is connected to the power grid. Aiming to provide reference strategies for relevant researchers as well as practical applications, this paper attempts to provide the literature investigation and methods analysis of deep learning, enforcement learning and transfer learning in wind speed and wind power forecasting modeling. Usually, wind speed and wind power forecasting around a wind farm requires the calculation of the next moment of the definite state, which is usually achieved based on the state of the atmosphere that encompasses nearby atmospheric pressure, temperature, roughness, and obstacles. As an effective method of high-dimensional feature extraction, deep neural network can theoretically deal with arbitrary nonlinear transformation through proper structural design, such as adding noise to outputs, evolutionary learning used to optimize hidden layer weights, optimize the objective function so as to save information that can improve the output accuracy while filter out the irrelevant or less affected information for forecasting. The establishment of high-precision wind speed and wind power forecasting models is always a challenge due to the randomness, instantaneity and seasonal characteristics
Approaches for multi-step density forecasts with application to aggregated wind power
The generation of multi-step density forecasts for non-Gaussian data mostly
relies on Monte Carlo simulations which are computationally intensive. Using
aggregated wind power in Ireland, we study two approaches of multi-step density
forecasts which can be obtained from simple iterations so that intensive
computations are avoided. In the first approach, we apply a logistic
transformation to normalize the data approximately and describe the transformed
data using ARIMA--GARCH models so that multi-step forecasts can be iterated
easily. In the second approach, we describe the forecast densities by truncated
normal distributions which are governed by two parameters, namely, the
conditional mean and conditional variance. We apply exponential smoothing
methods to forecast the two parameters simultaneously. Since the underlying
model of exponential smoothing is Gaussian, we are able to obtain multi-step
forecasts of the parameters by simple iterations and thus generate forecast
densities as truncated normal distributions. We generate forecasts for wind
power from 15 minutes to 24 hours ahead. Results show that the first approach
generates superior forecasts and slightly outperforms the second approach under
various proper scores. Nevertheless, the second approach is computationally
more efficient and gives more robust results under different lengths of
training data. It also provides an attractive alternative approach since one is
allowed to choose a particular parametric density for the forecasts, and is
valuable when there are no obvious transformations to normalize the data.Comment: Corrected version includes updated equation (18). Published in at
http://dx.doi.org/10.1214/09-AOAS320 the Annals of Applied Statistics
(http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics
(http://www.imstat.org
Reference wind farm selection for regional wind power prediction models
http://www.ewec2006proceedings.info/allfiles2/789_Ewec2006fullpaper.pdfInternational audienceShort-term wind power forecasting is recognized today as a major requirement for a secure and economic integration of wind generation in power systems. This paper deals with the case of regional forecasting of wind power with a large number of wind farms involved. Due to the large amount of potentially available information and also because part of the wind farms may not be "observable", forecasting systems use input from selected âreferenceâ wind farms to predict the total wind power. The paper studies the influence of the reference farms on the prediction accuracy and proposes a methodology for their selection, based on advanced statistical analysis of the spatial-temporal characteristics of wind generation. Keywords: regional forecasting, upscaling, reference farm selection, information, clustering the final objective. At a primary level the problem of variables selection can be simplified to a problem of wind farms selection. In this paper a study is conducted to evaluate the impact of input selection on regional forecasting model performance, and several input selection methods that can help in model setup are examined. The results of the proposed methodology are evaluated on a Danish case study of regional forecasting using a non-linear prediction model
Short-term power prediction for renewable energy using hybrid graph convolutional network and long short-term memory approach
Accurate short-term solar and wind power predictions play an important role
in the planning and operation of power systems. However, the short-term power
prediction of renewable energy has always been considered a complex regression
problem, owing to the fluctuation and intermittence of output powers and the
law of dynamic change with time due to local weather conditions, i.e.
spatio-temporal correlation. To capture the spatio-temporal features
simultaneously, this paper proposes a new graph neural network-based short-term
power forecasting approach, which combines the graph convolutional network
(GCN) and long short-term memory (LSTM). Specifically, the GCN is employed to
learn complex spatial correlations between adjacent renewable energies, and the
LSTM is used to learn dynamic changes of power generation curves. The
simulation results show that the proposed hybrid approach can model the
spatio-temporal correlation of renewable energies, and its performance
outperforms popular baselines on real-world datasets.Comment: This paper was accepted the 22nd Power Systems Computation Conference
(PSCC 2022
Power System Parameters Forecasting Using Hilbert-Huang Transform and Machine Learning
A novel hybrid data-driven approach is developed for forecasting power system
parameters with the goal of increasing the efficiency of short-term forecasting
studies for non-stationary time-series. The proposed approach is based on mode
decomposition and a feature analysis of initial retrospective data using the
Hilbert-Huang transform and machine learning algorithms. The random forests and
gradient boosting trees learning techniques were examined. The decision tree
techniques were used to rank the importance of variables employed in the
forecasting models. The Mean Decrease Gini index is employed as an impurity
function. The resulting hybrid forecasting models employ the radial basis
function neural network and support vector regression. Apart from introduction
and references the paper is organized as follows. The section 2 presents the
background and the review of several approaches for short-term forecasting of
power system parameters. In the third section a hybrid machine learning-based
algorithm using Hilbert-Huang transform is developed for short-term forecasting
of power system parameters. Fourth section describes the decision tree learning
algorithms used for the issue of variables importance. Finally in section six
the experimental results in the following electric power problems are
presented: active power flow forecasting, electricity price forecasting and for
the wind speed and direction forecasting
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