Electric energy production in a wind farm - the statistical analysis of measurement results using the time series

Author(s):  
Wieslawa Malska ◽  
Damian Mazur
2019 ◽  
Vol 84 ◽  
pp. 01001
Author(s):  
Paweł Piotrowski ◽  
Dariusz Baczyński ◽  
Marcin Kopyt ◽  
Karolina Szafranek

The most important factor responsible for the quality of energy production forecasts in wind farms is the accurate wind speed forecast. An extensive statistical analysis of meteorological data (NWP) from 16 base nodes of the "300" grid in the "Łódź" area was made. The intention of the statistical analysis was to select potential explanatory variables for models predicting wind speed in the remaining 206 nodes of the grid’s mesh. Next, tests of selected prognostic methods were performed in order to compare their effectiveness with bilinear method which is not computationally complex. It should be emphasized that the main problem in spatial wind speed forecasting is the very large number of nodes for which the forecasts are calculated. As a consequence, more advanced and computationally complex forecasting methods cannot be applied in practice due to too long calculations time and difficulties in huge amounts of data processing. Conclusions with proposals of preferred forecasting methods that could be used in practice were developed.


Author(s):  
Baldoino Sonildo Nóbrega ◽  
Waleria Guerreiro Lima ◽  
Raphael Henrique Falcão de Melo ◽  
Edvan Cruz Aguiar ◽  
Rute Cavalcante Pereira ◽  
...  

<p>The present work has the objective of presenting a fixed and solar tracker photovoltaic systems comparative study, through the technical and financial viability evaluation in a public education institution located in the backlands of the state of Paraíba (Brazil). Through a System Advisor Model simulation software, we estimated the electrical energy production of the systems. Then, we performed a statistical analysis to evaluate the differences between the energy production of the proposed systems. Finally, financial indicators were used to assess which system had better financial viability. The results on performance have shown that the annual production of electric energy for photovoltaic systems with tracking is 32% higher than the fixed system. Statistical analysis proved by hypothesis testing that there is evidence that the tracking system produces more electric energy in relation to the fixed system. As for financial evaluation, the fixed system was more advantageous, since its financial indicators were better in all aspects. The research contributed to a better understanding of the differences between photovoltaic systems in terms of technical, financial and statistical aspects, which may help the decision making when choosing the installation of these systems in the region which is being studied.</p>


2020 ◽  
Vol 48 ◽  
Author(s):  
Liudas Kaklauskas ◽  
Leonidas Sakalauslas

The present article deals with statistical university network traffic, by applying the methods of self-similarity and chaos analysis. The object of measurement is Šiauliai University LitNet network node maintaining institutions of education of the northern Lithuania region. Time series of network traffic characteristics are formed by registering amount of information packets in a node at different regimes of network traffic and different values of discretion of registered information are present. Measurement results are processed by calculating Hurst index and estimating reliability of analysis results by applying the statistical method. Investigation of the network traffic allowed us drawing conclusions that time series bear features of self-similarity when aggregated time series bear features of slowly decreasing dependence.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3615
Author(s):  
Adelaide Cerveira ◽  
Eduardo J. Solteiro Pires ◽  
José Baptista

Green energy has become a media issue due to climate changes, and consequently, the population has become more aware of pollution. Wind farms are an essential energy production alternative to fossil energy. The incentive to produce wind energy was a government policy some decades ago to decrease carbon emissions. In recent decades, wind farms were formed by a substation and a couple of turbines. Nowadays, wind farms are designed with hundreds of turbines requiring more than one substation. This paper formulates an integer linear programming model to design wind farms’ cable layout with several turbines. The proposed model obtains the optimal solution considering different cable types, infrastructure costs, and energy losses. An additional constraint was considered to limit the number of cables that cross a walkway, i.e., the number of connections between a set of wind turbines and the remaining wind farm. Furthermore, considering a discrete set of possible turbine locations, the model allows identifying those that should be present in the optimal solution, thereby addressing the optimal location of the substation(s) in the wind farm. The paper illustrates solutions and the associated costs of two wind farms, with up to 102 turbines and three substations in the optimal solution, selected among sixteen possible places. The optimal solutions are obtained in a short time.


Buildings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Thomas Danel ◽  
Zoubeir Lafhaj ◽  
Anand Puppala ◽  
Sophie Lienard ◽  
Philippe Richard

This article proposes a methodology to measure the productivity of a construction site through the analysis of tower crane data. These data were obtained from a data logger that records a time series of spatial and load data from the lifting machine during the structural phase of a construction project. The first step was data collection, followed by preparation, which consisted of formatting and cleaning the dataset. Then, a visualization step identified which data was the most meaningful for the practitioners. From that, the activity of the tower crane was measured by extracting effective lifting operations using the load signal essentially. Having used such a sampling technique allows statistical analysis on the duration, load, and curvilinear distance of every extracted lifting operation. The build statistical distribution and indicators were finally used to compare construction site productivity.


IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Yufei Li ◽  
Bo Hu ◽  
Tao Niu ◽  
Shengpu Gao ◽  
Jiahao Yan ◽  
...  

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