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Performance assessment of wind farms

Vaz, Clara B.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
66.79%
This study develops a methodology to provide insights regarding the performance of the wind farms of a European player in the energy sector. The focus of the wind farm performance assessment is on the operating stage which corresponds to the electrical energy generation process. Firstly, the Data Envelopment Analysis is used to measure the performance of wind farms in generating electrical energy from the resources available and exogenous variables, during the period under analysis. This analysis enables the identification of the best practices of the efficient farms which can be emulated by inefficient ones. Secondly, bootstrap procedures are applied to obtain statistical inference on the efficiency estimates. The performance assessment approach proposed will be useful for promoters in the management and control of wind farms and for the installation of wind farms in new areas, but also for repowering processes in existing farms.

Framework for performance assessment of wind farms

Vaz, Clara B.; Ferreira, Ângela P.
Fonte: José Fernando Oliveira; Clara Bento Vaz Publicador: José Fernando Oliveira; Clara Bento Vaz
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
56.67%
This study develops a framework to provide insights regarding the performance of the farms of an energy player in the Portuguese wind sector. Firstly, the Data Envelopment Analysis is used to measure the efficiency of wind farms in producing electrical energy from the resources available and exogenous variables, during operating stage. This analysis enables the identification of the best practices of the efficient farms which can be emulated by inefficient ones. Secondly, Malmquist index is used to evaluate the changes in wind farms productivity. Bootstrap procedures are applied to obtain statistical inference on the efficiency estimates.

Performance assessment of wind farms

Vaz, Clara B.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
56.57%
This study develops a methodology to provide insights regarding the performance of wind farms from a European player in energy sector. Firstly, the DEA is used to measure the performance of wind farms in generating electricity from the resources available and nondiscretionary variables such as wind (speed and availability). This analysis enables to identify the benchmarks whose best practices can be emulated by inefficient units and provides useful information for regulators in the sector. Secondly, bootstrap procedures are applied to obtain statistical inference on the efficiency estimates.

Framework for performance assessment of wind farms

Vaz, Clara B.; Ferreira, Ângela P.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
56.67%
This study develops a framework to provide insights regarding the performance of the farms of an energy player in the Portuguese wind sector. Firstly, the Data Envelopment Analysis is used to measure the efficiency of wind farms in producing electrical energy from the resources available and exogenous variables, during operating stage. This analysis enables the identification of the best practices of the efficient farms which can be emulated by inefficient ones. Secondly, Malmquist index is used to evaluate the changes in wind farms productivity. Bootstrap procedures are applied to obtain statistical inference on the efficiency estimates.

Wind farms model aggregation using probabilistic clustering

Fernandes, Paula O.; Ferreira, Ângela P.
Fonte: AIP Publishing LLC Publicador: AIP Publishing LLC
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
66.7%
The main objective of this research is the identification of homogeneous groups within wind farms of a major operator playing in the energy sector in Portugal, based on two multivariate analyses: Hierarchical Cluster Analysis and Discriminant Analysis, by using two independent variables: annual liquid hours and net production. From the produced outputs there were identified three homogenous groups of wind farms: (1) medium Installed Capacity and Induction Generator based Technology, (2) high Installed Capacity and Synchronous Generator based Technology and (3) medium Installed Capacity and Synchronous Generator based Technology, which includes the wind farms with the higher annual liquid hours. It has been found that the results obtained by cluster analysis are well classified, with a total percentage of correct classification of 97,1%, which can be considered excellent.

Controle e integração de centrais eólicas à rede elétrica com geradores de indução duplamente alimentados. ; Control and integration of wind farms to the power grid using doubly fed induction generators.

Silva, Kleber Freire da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/03/2006 PT
Relevância na Pesquisa
66.66%
Esta Tese trata do controle e integração de centrais eólicas à rede elétrica interligada, utilizando-se geradores de indução duplamente alimentados (GIDE). O objetivo principal da Tese foi desenvolver estratégias de controle discreto para o sistema de geração eólica, de forma a reduzir os impactos na qualidade da energia gerada, em função dos diversos regimes e transitórios de vento, que podem ocorrer no sítio eólico. Para o projeto do sistema de controle dos geradores foi adotada a técnica do controle vetorial, de forma a desacoplar o controle do fluxo das potências ativa e reativa entre o gerador e a rede elétrica. Visando caracterizar os diversos modos de operação do GIDE, com velocidades acima e abaixo da síncrona, foi desenvolvido um estudo de regime permanente do gerador, obtendo-se os limites de correntes, tensões e demais grandezas elétricas e mecânicas, para uma determinada faixa de velocidade. As principais estratégias de controle atualmente utilizadas pelos fabricantes de turbinas eólicas foram analisadas, destacando-se os aspectos da eficiência energética do conjunto turbina-gerador e da qualidade da energia. O projeto das malhas de controle dos conversores estáticos conectados ao circuito do rotor foi desenvolvido utilizando a técnica de controle discreto...

Novos usos do território no semiárido nordestino : implantação de parques eólicos e valorização seletiva nos municípios de Caetité (BA) e João Câmara (RN); New uses of territory in the semiarid of Brazil : instalation of wind farms and selective valorization of Caetité (BA) and Joâo Câmara (RN)

Mariana Traldi
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/08/2014 PT
Relevância na Pesquisa
56.71%
Desde 2004 no Brasil tem havido uma crescente expansão da instalação de parques eólicos para geração de energia elétrica. No Brasil a fonte hegemônica na produção de energia elétrica sempre foi à hídrica. Contudo, a partir da crise do Apagão de 2001, que resultou no déficit na oferta de energia no macrossistema elétrico brasileiro o Estado tem buscado aumentar a oferta de energia elétrica através da diversificação da matriz elétrica nacional. Entre as fontes que vem ganhando importância está a fonte eólica. Desta forma, apresentamos nesta dissertação um panorama dos novos usos do território que resultam da instalação dos parques eólicos nos municípios de João Câmara (RN) e Caetité (BA), localizados no semiárido brasileiro. Buscamos desmistificar afirmações que sustentam serem os parques eólicos promotores do desenvolvimento local e grandes vetores de incremento na arrecadação de tributos municipais e estaduais. Identificamos assim os nexos entre a instalação dos parques eólicos e as necessidades impostas aos lugares pelo macrossistema elétrico brasileiro.; Although, the hegemonic power in the production of electricity has always been hydroeletric, since 2004 has been an increasing expansion of the installation of wind farms for power generation. The crisis known as Blackout 2001 resulted in a deficit of energy supply in the Brazilian large technological system. As a solution the Brazilian state has decided to increase the supply of electricity through the diversification of the national energy matrix. Among the sources that is gaining importance is wind power. Thus...

Differential mortality of birds killed at wind farms in Northern Portugal.

Morinha, Francisco; Travassos, Paulo; Seixas, Fernanda; Martins, Ana; Bastos, Rita; Carvalho, Diogo; Magalhães, Paula; Santos, Mário; Bastos, Estela; Cabral, João Alexandre
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.63%
The Skylark Alauda arvensis had the highest overall mortality in ten Northern Portuguese wind farms surveyed between 2006 and 2011. Analysis from the integration of conventional and molecular techniques suggest a sex and age biased mortality affecting mainly adult males (90.9%), which may be related to their characteristic breeding male song-flights making them highly vulnerable to collision with wind turbines. The results highlight the added value of more complete population impact assessments that go beyond simple carcass identification at wind farms.

Do habitat characteristics determine mortality risk for bats at wind

Ferreira, Daniel; Freixo, Cláudia; Cabral, João Alexandre; Santos, Regina; Santos, Mário
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.61%
Worldwide efforts to develop sustainable methods of energy production have been increasing the use of renewable sources, with special emphasis on wind energy. Despite the clear environmental benefits associated with this type of technology, many studies have confirmed bat fatalities at wind farms, which raise concerns about the long-term effects of these structures on bat populations. To investigate the impact of windmills on bat species, we developed a spatially explicit agent-based model (ABM) to replicate the underlying behavioural mechanisms for individuals of the species Nyctalus leisleri involvedwhen navigating their habitats at a landscape level, and to simulate the associated mortality events. A set of environmental data layers was used to develop a grid representing a real landscape in termsof habitat types, foraging availability and collision-risk. Themodel variables were estimated using values fromliterature. The simulations confirmed the species predominant selection of specific foraging areas and its high mobility, evidenced by the maximum distances to roosts and home range sizes, highly correlated with the habitats coniferous forests and broadleaf forests. High wind speeds (≥4 m/s) were associatedwith a decrease in the number of expected fatalities...

Assessment of Power Quality Characteristics of Wind Farms

Estanqueiro, Ana; Tande, John O.; Lopes, J. Peças
Fonte: IEEE - Institute of Electrical and Electronics Engineers Publicador: IEEE - Institute of Electrical and Electronics Engineers
Tipo: Conferência ou Objeto de Conferência
Publicado em //2007 ENG
Relevância na Pesquisa
56.61%
In this paper the main parameters to assess the power quality of grid embedded wind farms are presented. International standards to assess and quantify the power quality of grid connected wind turbines exist for some years now, and are here extrapolated to wind farms aggregates when possible being the correspondent methodologies identified in the document. Recently, the grid code requirements posed a novel challenge to this technologic area, particularly since they were issued with national or local objectives and without particular normalized global concerns. The form how the international standards are evolving in order to cope both with the power systems industry local requirements, but also with the global wind turbine manufacturers principles is addressed in the paper.

Methodology to study the life cycle cost of floating offshore wind farms

Castro-Santos, Laura; Garcia, Geuffer; Diaz-Casas, Vicente
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
56.59%
The main objective of this paper is to determine a theoretical methodology process to study the life cycle cost of floating offshore wind farms. The principal purpose is adapting the LCC (Life-Cycle Cost Calculation) from several authors to the offshore wind energy world, providing a new method which will be called LCSFOWF. In this sense, several general steps will be defined: life cycle definition, process breakdown structure, viability study and sensitivity study. Moreover, technical and economic issues and their relations will be considered. On the other hand, six life cycle phases needed to install a floating offshore wind farm will be defined: conception and definition, design and development, manufacturing, installation, exploitation and dismantling. They will be useful to define the majority of the steps in the process. This methodology could be considered to calculate the real cost of constructing floating offshore wind farms.

Impact of weather conditions on the windows of opportunity for operation of offshore wind farms in portugal 

Silva, N.; Estanqueiro, Ana
Fonte: Multi-Science Publishing Publicador: Multi-Science Publishing
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
56.53%
The deployment of offshore wind parks face several challenges. Among them are the difficulties introduced by the atmospheric and sea conditions in accessing those wind parks. A window of opportunity is a timeframe when weather and sea conditions are acceptable and enable to perform specific tasks in the installation and operation/maintenance of the offshore wind park. This study identifies typical time periods of windows of opportunity to access three offshore Portuguese maritime regions. The accessibility conditions also take into account the system type transportation method for local access, namely, rubber boat, boat with OAS or helicopter. It was concluded that Portugal has adequate conditions for offshore site maintenance strategies, with a large number of windows of opportunity, but they are relatively short, therefore the installation of offshore wind parks must be carefully planned. This is an important factor in favor of the offshore wind farm deployments on the country.

Quantifying the visual effects of wind farms: a theoretical process in an evolving Australian visual landscape.

Grimm, Brett
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2009
Relevância na Pesquisa
66.8%
Renewable energy production takes on many forms; wind farms and their turbines are but one. Turbines are a unique dynamic infrastructure within the landscape, which signifies a change in social attitude towards sustainable developments. The clarity and simplicity of the turbines’ function (wind blows, blades turn, turbine spins and electrical power is generated) enforces the benign qualities that wind farms possess. However there are implications associated with the compatibility of turbines to landscape visual character and conservation. The environmental impacts associated with wind turbines include noise, shadow flicker, bird strikes and electromagnetic interference with radio and television signals. However, research suggests the major issue facing planning and development approval is on a social level, with visual pollution being the dominant public criticism. Wind farms must be located where consistent strong winds permeate to generate maximum efficiency. The efficiency of output is dependent on clear exposure to the prevailing wind, which normally implies ridgelines and escarpments which are both visually dominant topographical locations. The Australian Wind Energy Association (AUSWEA) has established guidelines confirming that smooth hilltops are the most preferred topography for airflow...

Gravity base foundations for offshore wind farms : marine operations and installation processes

Ruiz de Temiño Alonso, Ismael
Fonte: Universidade de Cantabria Publicador: Universidade de Cantabria
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
66.65%
ABSTRACT. Marine operations required in the installation of gravity base foundations for offshore wind farms were studied. This dissertation analyses the operations of transport, seabed preparation, installation and scour protection. This analysis was carried out through the study of the eight most relevant offshore wind farms with gravity base foundations, four significant foundation designs, and the application of techniques from other offshore construction sectors. Within each operation, the main procedures both used so far and expected for the future were investigated. It was also identified the main factors to consider in each operation and the means required. Further analysis studied different transport and installation configurations.; Máster europeo en Ingeniería de la Construcción

Sliding mode control in grid-connected wind farms for stability enhancement

Flórez Rodríguez, Diana Marcela
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Tese de Doutorado Formato: application/pdf
ENG
Relevância na Pesquisa
56.55%
Aiming at reducing the rather high percentage of CO2 emissions attributed to the electrical energy production industry, a new generation of power plants has been introduced which produce electricity by using primary energy resources which are said to be renewable, such as wind, solar, geothermal and biomass. This has had not only the benefit of reducing CO2 emissions into the atmosphere to a trickle, by the new power plants but to also encourage a great deal of technological advance in both the manufacturing sector and in research institutions. Wind power is arguably the most advanced form of renewable energy generation today, from the bulk energy production and economic vantages. This doctoral thesis rigorously deals with the analysis, assessment and description of the impact of double-fed variable speed wind turbine on the dynamic behaviour of both, the wind farm itself and its interconnection with the conventional power generation system. Analytical analysis of the results published in the open literature is used as a tool to gain a solid understanding of the dynamic behaviour of power systems with wind generation. The influence of the characteristics of the electrical system and wind turbines or external parameters on stability is assessed using modal analysis. Studies conducted have focused on the analysis of transient stability and small signal stability for the damping of oscillations in power systems and its enhancement. Analysis of small signal stability and transient stability analysis are carried out using modal analysis and dynamic simulations in the time domain. This thesis proposes the implementation of sliding mode control techniques for the DFIG WT converters...

Efficiency assessment of wind farms: a two-stage approach

Vaz, Clara B.; Ferreira, Ângela P.
Fonte: AIP Publishing Publicador: AIP Publishing
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
56.74%
This study proposes an integrated methodology to provide insights regarding the efficiency of wind farms of two major promoters in the Portuguese energy sector. The focus of the wind farms performance assessment is on the operating stage which corresponds to the electrical energy production process. In a first stage, Data Envelopment Analysis is used to measure the efficiency of wind farms in producing electrical energy from the resources available and exogenous variables. This method is complemented by bootstrapping to refine the efficiency estimates. In a second stage, the factors which may influence the performance of wind farms are investigated by using truncated regression with bootstrapping. The methodology proposed may be used by promoters in management of wind farms and may also be useful to regulator agents on the supervision of the energy market.

An avian relative fatality risk index for Iberian species on wind farms based on zero inflated count models; Índice de risco relativo de mortalidade de aves ibéricas em parques eólicos baseado em modelos inflacionados em zero

Soares, Maria João de Sousa
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
66.67%
Climate change is one of the greatest threats towards humankind and wildlife. This consciousness motivated the search for alternatives that could contribute to mitigate climate change. Betting on renewable energies seems to be a winning strategy adopted worldwide in order to reduce greenhouse gas emissions responsible for global climate alterations and to improve nations’ energy independency. However, nowadays, these energy usages still have negative impacts, mostly on wildlife. Wind energy is even considered the greatest unintended human impact on avifauna. In this context, the aim of this thesis was to increase the knowledge about wind farms impacts on avifauna, which variables influence birds’ fatalities by collision with wind turbines and birds’ vulnerability. Models based on excessive zero counts were tested to understand which variables influence birds’ fatalities assessed on 25 Portuguese wind farms. This allowed to estimate the probability of mortality observation per species. The information obtained was used to build the fatality risk index that also considered the vulnerability factors, which give information of species conservation concern and resilience. Those indexes allow to prioritise the existing and limited conservation efforts on more vulnerable species. Models and indexes are also important for improving knowledge about wind energy impacts on wildlife and what can lead to reduce them...

Dynamic models of wind farms for power system studies: status by IEA Wind R&D Annex 21

Tande, John O.; Muljadi, Eduard; Carlson, Ola; Pierik, Jan; Estanqueiro, Ana; Sorensen, Poul; O'Malley, Mark; Mullane, Alan; Anaya-Lara, Olimpo; Lemstrom, Bettina
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2004 ENG
Relevância na Pesquisa
66.61%
Dynamic models of wind farms for power system studies are at present not a standard feature of many software tools, but are being developed by research institutes, universities and commercial entities. Accurate dynamic wind farm models are critical; hence model validation is a key issue and taken up by IEA Wind R&D Annex 21. This international working group includes participants from nine countries, and has since start-up in 2002 developed a systematic approach for model benchmark testing. This paper present this methodology, including example benchmark test results, but also gives an overview of the various wind farm models now being available from both Annex partners and external entities.

Time-varying harmonic analysis of electric power systems with wind farms, by employing the possibility theory

Romero-Quete,Andrés Arturo; Suvire,Gastón Orlando; Zini,Humberto Cassiano; Rattá,Giuseppe
Fonte: DYNA Publicador: DYNA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 EN
Relevância na Pesquisa
56.53%
This paper focuses on the analysis of the connection of wind farms to the electric power system and their impact on the harmonic load-flow. A possibilistic harmonic load-flow methodology, previously developed by the authors, allows for uncertainties related to linear and nonlinear load variations to be modeled. Moreover, it is well known that some types of wind turbines also produce harmonics, in fact, time-varying harmonics. The purpose of this paper is to present an improvement of the former method, in order to include the uncertainties due to the wind speed variations as an input related with power generated by the turbines. Simulations to test the proposal are performed in the IEEE 14-bus standard test system for harmonic analysis, connecting to the network a wind farm composed by ten Full Power Converter (FPC) type wind turbines. Results obtained show that uncertainty in the wind speed has a considerable effect on the uncertainties associated with the computed harmonic voltage magnitudes.

Dynamic performance improvement of wind farms equipped with three SCIG generators using STATCOM

Hasnaoui,Othman; Allagui,Mehdi
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2014 EN
Relevância na Pesquisa
56.63%
The main causes of wind farms disconnection from the grid is the three-phase grid faults at the point common coupling (PCC) e.g. the voltage dip. The use of a Static Synchronous Compensator (STATCOM) which is from the family of Flexible AC Transmission System (FACTS) devices can be used effectively in a wind park based on FSIG to provide transient voltage and to improve wind system stability. Due to the asynchronous operation nature, system instability of wind farms based on FSIG (Fixed Speed Induction Generator) is largely caused by the reactive power absorption by FSIG because due to the large rotor slip during grid fault. STATCOM contributes to control the grid voltage at PCC and maintain wind farm connection to the grid during some severe conditions of grid faults and used for power flow control and for damping power system oscillations. The evaluation of this control strategy using (STATCOM) is investigated in terms of regulation reactive power and transient stability of the wind farm during grid disturbances.