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- cerpch

Comitê Diretor do CERPCH
Director Committee
CEMIG / FAPEPE / IEE-USP / FURNAS /
IME / ELETROBRAS / ANEEL / MME
Comitê Editorial
Editorial Committee
Presidente - President
Geraldo Lúcio Tiago Filho - CERPCH/UNIFEI
Editores Associados - Associated Publishers
Adair Matins - UNCOMA - Argentina
Alexander Gajic - University of Serbia
Alexandre Kepler Soares - UFMT
Ângelo Rezek - ISEE/UNIFEI
Antônio Brasil Jr. - UnB
Artur de Souza Moret - UNIR
Augusto Nelson Carvalho Viana - IRN/UNIFEI
Bernhard Pelikan - Bodenkultur Wien - Áustria
Carlos Barreira Martines - UFMG
Célio Bermann - IEE/USP
Edmar Luiz Fagundes de Almeira - UFRJ
Fernando Monteiro Figueiredo - UnB
Frederico Mauad - USP
Helder Queiroz Pinto Jr. - UFRJ
Jaime Espinoza - USM - Chile
José Carlos César Amorim - IME
Marcelo Marques - IPH/UFRGS
Marcos Aurélio V. de Freitas - COPPE/UFRJ
Maria Inês Nogueira Alvarenga - IRN/UNIFEI
Orlando Aníbal Audisio - UNCOMA - Argentina
Osvaldo Livio Soliano Pereira - UNIFACS
Regina Mambeli Barros - IRN/UNIFEI
Zulcy de Souza - LHPCH/UNIFEI
Editorial
Editorial
Curta
News
Opinion
Lei 13.097 altera tributação para energias renováveis
Law 13.097 changes renewable energy tax
Agenda 34
Schedule
Ficha catalográfica elaborada pela Biblioteca Mauá –
Bibliotecária Margareth Ribeiro- CRB_6/1700
R454
Revista Hidro & Hydro – PCH Notícias & Ship News, UNIFEI/CERPCH,
v.1, 1998 -- Itajubá: CERPCH/IARH, 1998 – v.15, n. 64,jan./mar. 2015.
Expediente
Editorial
Tradução
Impressão
06
Opinião
Prof. François AVELLAN, EPFL École Polytechnique Fédérale de Lausanne,
Switzerland, [email protected], Chair;
Prof. Eduardo EGUSQUIZA, UPC Barcelona, Spain, [email protected], Vice-Chair;
Dr. Richard K. FISHER, VOITH Hydro Inc., USA, [email protected], Past-Chair;
Mr. Fidel ARZOLA, EDELCA, Venezuela, [email protected];
Dr. Michel COUSTON, ALSTOM Hydro, France, [email protected];
Dr. Niklas DAHLBÄCK, VATENFALL, Sweden, [email protected];
Mr. Normand DESY, ANDRITZ Hydro Ltd., Canada, [email protected];
Prof. Chisachi KATO, University of Tokyo, Japan, [email protected];
Prof. Jun Matsui, Yokohama National University, [email protected];
Dr. Andrei LIPEJ, TURBOINSTITUT, Slovenija, [email protected];
Prof. Torbjørn NIELSEN, Norwegian University of Science and Technology, Norway,
[email protected];
Mr. Quing-Hua SHI, Dong Feng Electrical Machinery, P.R. China, [email protected];
Prof. Romeo SUSAN-RESIGA, “Politehnica” University Timisoara, Romania, [email protected];
Prof. Geraldo TIAGO F°, Universidade Federal de Itajubá, Brazil, [email protected].
Geraldo Lúcio Tiago Filho
Camila Rocha Galhardo
Adriana Barbosa MTb-MG 05984
Adriana Barbosa
Camila Rocha Galhardo
Net Design
Lidiane Silva
06
A Viabilidade de Aplicação da Resolução 482 na Implantação de
Sistemas de Geração Fotovoltaica nas Atuais Condições de Mercado
Application Feasibility of Resolution 482 in the Implementation of
Solar Power Systems in the Current Market Conditions
TECHNICAL COMMITTEE
Editor
Coord. Redação
Jornalista Resp.
Redação
Projeto Gráfico
Diagramação e Arte
04
Trimestral.
Editor chefe: Geraldo Lúcio Tiago Filho.
Jornalista Responsável: Adriana Barbosa – MTb_MG 05984
ISSN 2359-6147 / ISSN 1676-0220
1. Energia renovável. 2. PCH. 3. Energia eólica e solar. 4. Usinas hi_
drelétricas. I. Universidade Federal de Itajubá. II. Centro Nacional de Re_
ferência em Pequenas Centrais Hidrelétricas. III. Título.
Joana Sawaya de Almeida
Editora Acta Ltda
Hidro&Hydro - PCH Notícias & SHP News
é uma publicação trimestral do CERPCH
The Hidro&Hydro - PCH Notícias & SHP News
is a three-month period publication made by CERPCH
Tiragem/Edition: 6.700 exemplares/issues
contato comercial: [email protected] / site: www.cerpch.org.br
Universidade Federal de Itajubá
ISSN 2359614-7
Av. BPS, 1303 - Bairro Pinheirinho
Itajubá - MG - Brasil - CEP: 37500-903
e-mail: [email protected]
[email protected]
Fax/Tel: +55 (35)3629 1443
9 772359 614009
00064
3
EDITORIAL
HIDRO&HYDRO: PCH NOTÍCIAS & SHP NEWS, 64 (5), JAN,FEV,MAR/2015
Dear readers,
Prezado Leitor,
Ao longo dos últimos 17 anos a revista PCH Notícias &SHP News
passou por diversas transformações buscando se adequar a época e as
necessidades do mercado. A publicação que foi concebida com intuito de
divulgar notícias e a produção científica na área de pequenas centrais
hidrelétricas. Nos últimos anos foram feitas adequações para ampliar a sua
abrangência, passando a ser denominada Hidro & Hydro com publicação
de matérias e artigos científicos de outras fontes de energias renováveis.
Entretanto a proposta não se mostrou adequada. Desta forma, a partir
dessa primeira edição do ano a revista foi desdobrada em duas publicações
independentes, onde a Hidro & Hydro com ISSN próprio publicará em
páginas coloridas matérias e reportagens sobre temas relevantes ao
setor elétrico. É essa revista que, a partir de agora, estampará os apoios
institucionais, tão importantes a esta revista, visto que é com o apoio
dos anunciantes que a revista pode publicada. Já a PCH Notícias &SHP
News se dedicará exclusivamente para a divulgação de produção científica
com o ISSN já existente. Assim, pretende-se segmentar os conteúdos de
maneira a não perder a credibilidade conquistada nesses anos.
Vale ressaltar que a publicação continuará sendo de distribuição
gratuita e as mesmas serão impressas juntas.
Para a submissão de artigos técnicos na revista, o pesquisador
agora deverá submetê-lo por meio do site www.cerpch.org.br onde está
disponibilizada uma plataforma em que o autor terá acesso a todas as
etapas de avaliação e no final da avaliação e com sua aprovação o artigo
será indexado com o respectivo Digital Object Identifier – DOI, identificação
esta que auxilia na referencia do mesmo para citações.
Por fim, o comitê editorial da revista visa cada dia mais fazer com
que a publicação seja referência para seus leitores, colaboradores e
patrocinadores.
Esperando continuar a contar com o apoio e colaboração de todos.
Over the last 17 years, the magazine PCH Notícias & SHP News has
gone through several transformations in order to adapt to market times
and needs. Its publication was conceived with the intention of spreading
the news and scientific production on small hydropower plants. In the last
few years, adjustments were made in order to branch out its reach, with
adjustments such as the new name Hidro & Hydro as well as publications of
scientific articles and subjects of other renewable sources.
However, it did not prove to be enough. Therefore, for this first edition
of 2015, the magazine has been divided into 2 independent publications,
Hidro & Hydro and PCH Notícias & SHP News. Hidro & Hydro now has
its own ISSN and will be publishing color printed articles and reports on
themes relevant to the electric sector. This is the magazine that here on
out will print the institutional support which is tremendously important to
the magazine, as it is with those advertisements that the magazine can
be published. The other, PCH Notícias & SHP News, will be exclusively
dedicated to promoting scientific productions with the existing ISSN. The
content is intended to be segmented, so as not to lose the credibility that
has been attained over the years.
It is worth mentioning that both magazines will continue to be distributed
free of charge and both will also be printed together as one.
For the submission of technical articles in the magazine, the researcher
must now submit it through the website: www.cerpch.org.br where the
author can have access to all of the approval stages, from evaluation to
final approval of the article. Articles will be indexed with the Digital Object
Identifier – DOI, the identification that aids in referencing citations.
On a final note, the editorial committee of the magazine is aiming to
continuously make it so this publication is made a reference to the readers,
collaborators and sponsors.
Hoping to continue to count on everyone’s support and collaboration.
Enjoy reading!
Boa Leitura!
Apoio:
IAHR DIVISION I: HYDRAULICS
TECHNICAL COMMITTEE: HYDRAULIC MACHINERY AND SYSTEMS
4
5
CURTAS
A VIABILIDADE DE APLICAÇÃO DA RESOLUÇÃO 482 NA IMPLANTAÇÃO DE
SISTEMAS DE GERAÇÃO FOTOVOLTAICA NAS ATUAIS CONDIÇÕES DE MERCADO
Geraldo Lúcio Tiago Filho, 1Luzia Silva Riêra Salomon, 1Laura Campello Dardot,
1,2
Roberto Meira
1,2
Fonte: Salomon, L R, GEER/CERPCH – Unifei- 2014.
Source: Salomon, L R, GEER/CERPCH - UNIFEI - 2014.
em grande parte, isento desse custo extra, de forma a evitar a
O texto a seguir compreende a conclusão das discussões
perda de competitividade da indústria alemã. O modelo deu tão
desenvolvidas pelo Grupo de Estudos em Energias Renováveis
certo que o país aumentou mais de 300 vezes sua geração de
– GEER e Centro Nacional de Referências em PCH – CERPCH, da
energia solar nos últimos 11 anos e se tornou o líder global no
Universidade Federal de Itajubá- UNIFEI e tem como objetivo
quesito com 36% das placas fotovoltaicas em operação no mundo,
contribuir com as discussões nacionais sobre a sustentabilidade
e mais de 65% dos geradores são indivíduos ou comunidades.
energética e ambiental da matriz elétrica nacional.
No Brasil, os painéis fotovoltaicos, assim como os aerogeradores,
O diretor-geral da Agência Nacional de Energia Elétrica
são desonerados. Entretanto os custos ainda são altos, que
(ANEEL), Romeu Rufino, anunciou que o governo estuda a
dificultam, ou até mesmo impedem, a sua proliferação. Em
criação de um pacote de medidas para estimular a microgeração
estudo desenvolvido Salomon (2014), pesquisadora do Grupo de
distribuída no país, ou seja, a geração de energia por pequenos
Estudos em Energias Renováveis-GEER, da Universidade Federal de
consumidores, de forma descentralizada. Dentre as principais
Itajubá, mostra que o custo dos painéis solares para o atendimento
medidas estão, a criação de uma linha de crédito para aquisição de
residencial, considerando a demanda de energia requerida variando
equipamentos como placas solares, biodigestores e conversores,
de 5 a 25 kWh/dia, como mostra o Gráfico 1 a seguir. Por exemplo,
de modo que os pequenos consumidores possam gerar a própria
de acordo com o Gráfico 1, para uma residência que gaste em média
energia e, eventualmente, “vender” o excedente produzido à
210 kWh por mês, por exemplo, e a radiação solar local for de 4
distribuidora local, o que hoje não é permitido no Sistema de
kWh/m2/dia, o custo estimado para a implantação de um sistema
Compensação definido pela Resolução Normativa nº 482/2012
fotovoltaico será por volta de R$ 18.000,00.
da ANEEL.
Este mesmo gráfico mostra que o custo dos sistemas
A atual legislação prevê que a energia injetada pela unidade
fotovoltaicos para atendimento residencial pode variar de R$
consumidora por meio da microgeração distribuída seja cedida
11.000,00 a R$ 92.000,00, conforme a incidência solar na
à distribuidora local e posteriormente compensada, através de
localidade.
créditos, pela mesma unidade consumidora. E se, em um prazo
Como a radiação média no Brasil é de 4,5 kWh/dia, podede 36 meses, a energia injetada na rede não for consumida pelo
se supor que há grande possibilidade de se implantar sistemas
microgerador, o saldo de energia é apropriado pela distribuidora.
fotovoltaicos. Entretanto, para que se viabilize economicamente a
Com esta proposta do Diretor Geral da Aneel, também entra na
demanda a ser atendida deverá ser a partir de 25 KWh/dia, muito
pauta de discussão a incidência do ICMS sobre a comercialização
alta, que corresponde às residências de famílias com alto poder
do excedente de energia visto que, atualmente, apenas Minas
aquisitivo ou em instalações comerciais e pequenas indústrias.
Gerais e o Ceará deixam de tributar essa transação no Sistema
de
Compensação.
As
duas medidas são muito
importantes para que o
mercado da microgeração
finalmente deslanche no
Brasil. O alto custo dos
equipamentos e a falta
de incentivo na produção
do excedente de energia
tornam o prazo de retorno
muito longo e o investimento
pouco atraente.
Em países da Europa
como a Alemanha, por
exemplo, desde 2000 o
governo promove medidas
de incentivo a microgeração,
principalmente
a
fotovoltaica. Lá, o cidadão que
instala painéis solares em
casa tem a garantia de
vender a energia gerada
por um preço mais alto
Gráfico 1: Investimento necessário para implantação de painéis fotovoltaicos em função da demanda
que a média do mercado, e
de energia requerida e da incidência da radiação solar local.
esse subsídio é pago pelos
Graph 1: Investment necessary for solar panel implementation based on required energy and local
consumidores finais na
solar radiation.
forma de uma sobretaxa.
Mas o setor industrial ficou,
Grupo de Estudos de Energias Renováveis- GEER – UNIFEI.
Centro Nacional de Referências em PCH – CERPCH – UNIFEI, Universidade Federal de Itajubá - UNIFEI
1
2
6
NEWS
HIDRO&HYDRO - PCH NOTÍCIAS & SHP NEWS | ISSN 1676-0220
APPLICATION FEASIBILITY OF RESOLUTION 482 IN THE IMPLEMENTATION
OF SOLAR POWER SYSTEMS IN THE CURRENT MARKET CONDITIONS
Translation: Joana Sawaya de Almeida
The following contains the discussion
conclusions
developed
by
the
GEER
(Renewable Energy Discussion Group) and the
CERPCH (National Reference Center for SHPs)
of the Federal University of Itajubá - UNIFEI
with an objective to contribute to national
discussions regarding power and environment
sustainability of the national energy matrix.
Romeu Rufino, director-general of the
National Electric Energy Agency (ANEEL),
announced that the government is studying a
new set of measures to stimulate micro power
production in the country, i.e., power production
by consumers in a decentralized way.
One of the main measures is to establish
a line of credit for the acquisition of
equipment such as solar panels, biodigesters
and converters, so that consumers could
generate their own power and eventually
"sell" the surplus to the local distributor.
Today, this is something not yet allowed in
The Compensation System established by the
Normative Resolution 482/2012 of ANEEL.
Current legislation foresees that small
consumer generated power production be
passed on to the local distributor which would
later compensate the consumer through credits.
If in 36 months the micro producer does not use the injected
power in the grid, the distributor would appropriate it.
With this proposal from the director-general of ANEEL,
the incidence of the ICMS tax (Services Tax over Merchandise
Circulation) of surplus energy is also being discussed since
only Minas Gerais and Ceará states currently do not tax these
transactions in the Compensation System. The two measures are
extremely important for the micropower production market to
finally take off in Brazil.
The high equipment costs and lack on incentives in the surplus
energy production make the return on investment very long and
unattractive.
European countries like Germany, for example, have promoted
incentive measures for micropower production, especially solar
power, since 2000.
In Germany, citizens who install solar panels in their homes
are guaranteed to sell the generated power for a higher than
average market price and those subsidies are passed on to the
consumers in the form of a surcharge.
The German industrial sector was largely exempt from this
surcharge in order to avoid losing competitiveness.
This model worked so well that Germany's solar power
production increased 300 fold in the last 11 years. It became
the global leader in the sector with 36% of all solar panels in
operation worldwide with more than 65% of power production
coming from individuals or communities.
In Brazil, solar panels as well as wind turbines are tax exempt.
However, the cost is still high, hindering or even preventing
their proliferation.
A study by Salomon (2014), a GEER (Renewable Energy
Discussion Group) researcher of the Federal University of Itajubá
shows the cost of solar panels for residential use considering the
daily energy demand of 5 to 25 kWh, as shown in graphic 1.
For example, according to Graph 1, for a home that uses, on
average 210 kWh per month, and with a local solar radiation of 4
kWh/m² per day, the estimated cost for the implementation of a
solar panel system would be around R$ 18,000.00 reais.
The same graphic shows the cost of solar systems for
residential use ranging between R$11,000.00 and R$92,000.00
Since average daily solar radiation in Brazil is 4.5 kWh, one
can assume that there is a great possibility of implementing solar
power systems.
However, in order to make it economically feasible, the
demand must be higher than 25 kWh/daily inline with homes of
high purchasing power or in commercial installations and small
industries.
With the current available financing conditions, the system
is only economically feasible in areas of high solar radiation of
around 6 kWh/daily and with power demands higher than 15
kWh/daily.
This amount of solar radiation is found in the northeast region
of Brazil where the profile of the local consumer, whose purchasing
power is not very high, must be taken in consideration.
According to Laura Dardot (2014), if one considers just
savings on the electric bill alone without the sale of the surplus
energy, the financing interest rate would have to be below 6%
in order to make solar power systems attractive, considering an
investment return of 30 years.
On the other hand, if the consumer were to invest in a solar
system 60% larger than its needs, the investment would become
Renewable Energy Study Group - GEER - UNEIFEI
National Reference Center at PCH – CERPCH – UNIFEI, Universidade Federal de Itajubá - UNIFEI
1
2
7
CURTAS
Nas atuais condições de financiamento disponíveis, o sistema só se
viabiliza economicamente em regiões
com alta radiação solar, em torno de 6
kWh/dia e para demanda superiores a
15 KWh/dia. Esta radiação é encontrada
na região nordeste do Brasil, onde se
deve ser levada em consideração o perfil
do consumidor local, cujo poder aquisitivo, em sua maioria, não é muito alto.
De acordo com o estudo de Laura Dardot
(2014), se considerarmos somente o custo
evitado da conta de energia elétrica, sem
venda de excedente, a taxa de juros para
financiamento teria que estar abaixo de 6%
para que o investimento em um sistema
fotovoltaico seja atraente, considerando um
tempo de retorno de 30 anos.
Por outro lado, se o consumidor investisse em um sistema fotovoltaico 60%
maior que sua demanda, o investimento
se tornaria atraente se o excedente fosse
vendido a uma tarifa de R$ 0,90/kWh,
um valor abaixo da tarifa cobrada aos
grandes consumidores hoje no horário de
ponta, considerando uma taxa de juros
de 12% e o mesmo tempo de retorno de
30 anos.
Para que o investidor tivesse um
tempo de retorno do investimento menor,
de 15 anos, considerando este último cenário analisado, a tarifa
viável para venda do excedente já seria cerca de R$ 1,20/kWh.
Ou seja, é preciso fazer um arranjo entre a taxa de juros a ser
praticada no financiamento dos equipamentos e a tarifa de venda
do excedente de energia produzido pelo pequeno consumidor,
para que essas medidas sejam eficientes no sentido de incentivar
a microgeração distribuída no país.
Para desvincular de forma efetiva da tendência de dimensionamento apenas pela demanda, é necessário que a microgeração
fotovoltaica seja atrativa ao “consumidor/gerador local.” É emergencial a necessidade de revisão na Resolução Normativa ANEEL
n.º 482/2012 no tocante à possibilidade de venda de energia
gerada excedente, tal como já ocorre em alguns países europeus,
por exemplo.
A efetiva inserção dessa energia distribuída depende de um
cenário sob a égide da tríade: técnica, econômica e mercado. A
análise deve ser sistêmica e multifocal, permitindo ao consumidor
o melhor arranjo em todos esses aspectos.
Torna-se necessária a definição de uma política pública mais
eficiente para a geração distribuída, além do proposto na Resolução
Normativa citada. Esta questão deve ser efetivamente inserida
no contexto do planejamento energético nacional com a definição
de ações de incentivos de médio e longo prazo no tocante à
comercialização e distribuição dessa energia.
Cabe ao Ministério de Minas e Energia capitanear esta ação e
promover de forma sustentável esta opção de geração, indicando
aos investidores nacionais e internacionais, a potencialidade do
mercado, as condições de venda dessa energia e, principalmente,
em conjunto com outros órgãos públicos competentes, as
condições de incentivos governamentais.
Há um enorme potencial de aplicação desta alternativa
tecnológica no Brasil. Temos sol suficiente e uma cadeia
tecnológica madura relacionada à eletrônica e controle,
advinda da inserção de outras fontes alternativas renováveis.
O necessário agora é promover um ganho de escala nesta
aplicação, com regras de financiamento factíveis e incentivos à
qualificação e capacitação técnica para a efetiva inserção desta
geração distribuída no Brasil.
Neste sentido, o GEER/CERPCH propõe ao Ministério de Minas e
Energia reavaliar a Resolução Normativa n.º 482/2012, bem como
elaborar um estudo de um modelo de financiamento juntamente
com os bancos oficiais de forma a contribuir efetivamente na
política de diversificação da matriz energética nacional.
Dardot, Laura, “Micro Geração Fotovoltaica Residencial: Estudo de Caso na Região Rural de Itajubá“, Seminário
Interno GEER, UNIFEI, 2014.
Dardot, Laura, "Micro Residential Solar Power Production" Case study in the Rural Region of Itajubá", In-house
Seminar GEER, UNIFEI, 2014.
Salomon, Luzia R, “título do artigo Análise de viabilidade técnico econômica da geração solar fotovoltaica aplicada
no setor de consumo Residencial, no Brasil” Seminário Interno, GEER, UNIFEI, 2014.
Salomon, Luzia R, Article title: "Análise de viabilidade técnico econômica da geração solar fotovoltaica aplicada no
setor de consumo Residencial no Brasil”. In-house Seminar GEER, UNIFEI, 2014.
8
NEWS
attractive if the surplus could be sold at R$
0.90/kWh, a rate lower than what consumers
currently pay during peak hours, considering an
interest rate of 12% and the same investment
return of 30 years.
Considering this last scenario, the investor
would need to sell the surplus energy produced
at a rate of R$ 1,20/kWh for a return on
investment of less than15 years.
In other words, there must be a balance
between the financing interest rate of the
equipment and the price of the surplus energy
produced by the consumer for these measures
to be efficient in stimulating micropower
production in the country.
To effectively disassociate the tendency to
scale simply by demand, it is important that
micro solar power production be attractive to
the "local producer/consumer". There is an
urgent need for ANEEL to revise the Normative
Resolution 482/2012 to allow the sale of the
produced surplus energy, as already seen in
some European countries.
The effective implementation of this
distributed energy is dependent on a scenario
under the aegis of the technical, economic and
market triad.
The analysis must be systemic and multifocal allowing the
consumer a better arrangement in all aspects.
It is necessary to define a more efficient public policy for the
distributed production, in addition to the proposed Normative
Resolution cited.
This issue should effectively be put in the context of the
national energy planning with defined medium and long-term
incentives for the marketing and distribution of that energy.
It is the responsibility of the Ministry of Mines and Energy
to lead with this action and sustainably promote this generating
option by showing national and international investors the market
potential, energy sales conditions and the types of government
incentives especially in conjunction with other public agencies.
There is a huge potential for the implementation of this
alternative technology in Brazil.
Brazil has enough sunshine and a mature electronics and
control technological chain from the inclusion of other alternative
renewable energy sources.
The need now is to promote a gain of scale in this application,
with practical funding rules and incentives for training and
technical leadership to effectively apply this production
throughout Brazil.
In this respect, GEER and CERPCH are proposing that the
Ministry of Mines and Energy reevaluate the Normative Resolution
482/2012 and conduct a funding model study with the official
banks in order to effectively contribute to the diversification of
the national energy policy.
Movidos por desafios
www.snef.com.br
[email protected]
51 31 2103-2200
A SNEF dispõe de equipe e
know-how em serviços de
reforma e modernização
de equipamentos
eletromecânicos para
usinas hidrelétricas e
subestações.
Profissionais qualificados
para atuar em gerenciamento, projeto, fabricação,
montagem, comissionamento e diagnóstico.
Reforma e Modernização de
Usinas Hidrelétricas e Subestações
9
28 e 29 de ABRIL de 2015
UNIVERSIDADE NACIONAL DE LA PLATA, FACULDADE DE ENGENHARIA, DEPARTAMENTO DE HIDRÁULICA, LA PLATA, ARGENTINA
TEMARIO
O Grupo de Trabalho Latino Americano do Comitê de Máquinas
Hidráulicas e Sistemas da IAHR, tem o prazer de convidá-lo ao
II Latin American Hydropower and Systems Meeting onde se
encontrarão proﬁssionais e pesquisadores da área de
máquinas hidráulicas.
Para mais informações e submissão de artigos cientíﬁcos, por
favor visite nosso site.
www.latiniahr.org/meeting
RESERVE
A DATA
PROMOÇÃO
MÁQUINAS HIDRÁULICAS
SISTEMAS DE CONTROLE E MONITORAMENTO
MODELAGEM E SIMULAÇÃO
FENÔMENOS DE TRANSPORTE
APROVEITAMENTO HIDROENERGÉTICO
SISTEMAS DE BOMBEAMENTO
TECNOLOGIA OCEÂNICA
MERCADO ENERGÉTICO
EFICIÊNCIA ENERGÉTICA
ESTUDOS DE CASOS
GRUPO DE TRABALHO LATINO AMERICANO – COMITÊ DE MÁQUINAS HIDRÁULICAS E SISTEMAS DA IAHR
Durante a realização do “25th IAHR Symposium on Hydraulic Machinery and Systems”, realizado em setembro de 2010 na Romênia, foi
lançada a proposta de criação de um grupo latino americano para ampliar as discussões na área de máquinas hidráulicas e sistemas sob
a coordenação da "International Association for Hydraulic Research". Até o momento, o grupo possui 19 entidades participantes, entre
elas, ALSTOM, ANDRITZ, IMPSA, KSB, VOITH e as Universidades: IME, UFMG, UFMT, UFRGS, UFRJ, UnB, UNICAMP,
UNIFEI,USP e as Argentinas UNAM, UNCOMA, UNCU, UNLP, UTN - Regional Mendoza.
ORGANIZAÇÃO
latinamerican
WORKING GROUP
Universidad
Nacional
de La Plata
11
OPINIÃO
LEI 13.097 ALTERA TRIBUTAÇÃO PARA ENERGIAS RENOVÁVEIS
Da Redação
A Lei 13.097 sancionada pela presidente, Dilma Rousseff, em
20 de janeiro de 2015 traz algumas alterações no que se diz
respeito a energias renováveis, em especial a energia eólica e as
pequenas centrais hidrelétricas.
A iniciativa de desoneração tributária de partes utilizadas em
aerogeradores vem ao encontro da proposta da Medida Provisória
n.º 656/2014. Entretanto a redação sancionada em lei pode
ser considerada tacanha, uma vez que limita demasiadamente
o alcance do benefício, excluindo componentes e insumos que
não se enquadram no “Ex 01 do código 8503.00.90 da TIPI” não
foram contemplados pela norma outros importantes componentes
utilizados como insumos na fabricação de aerogeradores, dentre
os quais as próprias torres. Deixaram também de ser mencionadas
a prestação de serviços e as locações de máquinas, aparelhos,
instrumentos e equipamentos.
Na opinião dos pesquisadores do CERPCH, essa mudança
pode impactar de forma favorável para o crescimento de
empreendimentos eólicos no país, facilitando a aquisição de
sistemas de geração eólica. Mas, por outro lado, essa desoneração
para importação dificulta o incentivo para o desenvolvimento de
tecnologia nacional, gerando pouco interesse das empresas em
investir no desenvolvimento tecnológico nacional.
O grupo entende que a redução de alíquotas relacionadas à
importação podem induzir uma abertura maior de mercado a
produtos importados, com possíveis impactos na cadeia nacional
Dessa forma, entende-se que pode haver uma retração da cadeia
nacional uma vez que muitos insumos continuam tributados e desta
maneira pode ocorrer que os valores praticados comercialmente
sejam superiores aos produtos vindos do exterior.
A redefinição do aproveitamento do potencial hidráulico é
um assunto que vem sendo debatido no governo desde 2008, a
destacar o Projeto de Lei nº 4.004/2008, a Medida Provisória n.º
450/2009 e a Lei nº 11.943/2009. Mesmo após essas revisões a
Lei n.º 9.427/1996 continuava em desfavor dos autoprodutores.
12
Devido ao atual cenário da geração de
energia elétrica brasileiro, submetido à uma forte
restrição hídrica e em vias de racionamento, os
pesquisadores do CERPCH analisaram os termos
aprovados nesta lei e concluíram que: a ampliação
da potência das CGHs para 3 MW irá promover
uma desburocratização do processo junto à
Agência Nacional de Energia Elétrica. Atualmente,
com base no Relatório de Acompanhamento de
Estudos e Projetos de Usinas Hidrelétricas da
Superintendência de Concessões e Autorizações
de Geração da própria agência, tramitam
atualmente 1.798 pedidos de autorizações para
PCHs no âmbito da agencia, totalizando 15.610
MW de potência instalada. Desse universo, 502
empreendimentos hidrelétricos então entre 1 e 3
MW, correspondendo a um total de 977 MW de
potência instalada. Com esta nova Lei 28% dos
empreendimentos hidroenergéticos passam ter
como atração a simplicidade burocrática junto
ao órgão regulador. Isto pode ser um motivador
à efetiva instalação desses empreendimentos,
o que significa num cenário de 20 anos, a
possibilidade destas CGHs gerarem cerca de 3 mil
empregos diretos e indiretos por ano e fomentar
um mercado de aproximadamente de 6 bilhões
de reais.
Ressalta-se que o relatório da Aneel abrange registros em
níveis de análise distintos, tais como as etapas de registro,
análise e aprovação de estudos de inventário hidrelétrico de bacias
hidrográficas, estudos de viabilidade e projeto básico de usinas
hidrelétricas (UHEs), bem como de projeto básico de pequenas
centrais hidrelétricas (PCHs). E dependerá do empreendedor
a ação de proceder o registro destes empreendimentos nestas
novas condições.
A Lei também deveria tratar da
desoneração da biomassa. Entretanto,
os artigos que previam a desoneração
do PIS/PASEP sobre a transferência de
vapor e de biomassa para unidades de
cogeração, itens incluídos na Medida
Provisória 656, que originou esta Lei,
foram vetados pela presidente Dilma
Rousseff, sem os incentivos fiscais,
essas fontes de energia perderão
atratividade no mercado de energia,
uma vez que outras fontes renováveis
já recebem estes subsídios do
governo.
Com relação à desoneração das
tarifas de transmissão de energia
elétrica (TUST e TUSD), houve um
nivelamento entre as diferentes fontes,
a de energia solar, que contava com uma
amortização que variava entre 80% a
100% passará a ter uma amortização
que pode variar de 50% a 100%, tal
como já ocorre com as PCHs, ou seja,
com esta ação houve um nivelamento
destas fontes às PCHs.
OPINION
LAW 13.097 CHANGES RENEWABLE ENERGY TAX
Translation: Joana Sawaya de Almeida
Law 13.097, sanctioned by President Dilma Rousseff on January
20th 2015, brings some changes with regard to renewable energy;
particularly wind power and small hydroelectric power plants.
The tax exemption initiative for parts used in wind turbines
comes inline with the proposal of the Provisional Measure
656/2014.
However, the wording in the enacted law can be considered
narrow since it limits the scope of the benefit by excluding
components and supplies that do not fit the "Ex 01 8503.00.90 of
the TIPI code". The law did not cover other important components
such as supplies for wind power manufacturing and the actual
towers themselves.
Other items like, rental and maintenance of machinery,
equipment and instruments were also failed to be mentioned.
In the opinion of CERPCH researchers, this change could
favorably impact the growth of wind power investment in the
country, by aiding in the acquisition of wind power systems.
On the other hand, import tax exemptions hinder the
incentive for the development of national technologies, which in
turn creates very little investment interest from companies.
The group believes that import tax exemptions can lead to
the market opening up to imports with a possible impact on the
national product chain. Since large numbers of supplies continue
to be taxed, there may be a retraction in the national chain due
to the higher commercial costs compared to the imports.
Redefining the use of the hydroelectric power potential is
a subject that has been debated within the government since
2008, notably with Proposed Bill 4.004/2008, Interim Measure
450/2009 and Law 11.943/2009.
Producers continue hampered even after the revisions of the
Law 9.427/1996.
Due to the current Brazilian electric power production scenario,
which is under severe water restriction and undergoing rationing,
<s0/> CERPCH researchers analyzed the terms approved in this
law and concluded that: the increase of Hydroelectric Power Plants
capacity to 3 MW will remove the red tape from the process at the
National Electric Energy Agency.
Currently, based on the agency’s own Study and Followup Report of Hydroelectric Power Plants Projects from the
Concessions and Permits Administration (SCG), there are
currently 7.798 Small Hydroelectric Power Plant permits awaiting
approval, totaling 15.610 MW of installed capacity.
Of those, 502 hydroelectric projects range between 1 and 3
MW representing a total of 977 MW of installed capacity.
With this new law, 28% of the hydroelectric projects will now
benefit from less red tape from the regulatory agency.
This could be a motivating factor for the actual installation
of those hydroelectric projects. In 20 years these SHPs could
create three thousand direct and indirect jobs a year and fuel the
economy by approximately six billion reais.
It should be noted that the ANEEL report encompasses
records in distinct levels of analysis such as, registration steps,
review and approval of hydropower river
basin inventory studies, project feasibility and basic design
studies of hydropower plants (HPPs) as well as basic design of
small hydroelectric power plants (SHP).
It is up to the investor to proceed with the registration of
those projects under these new conditions.
The law should also deal with the tax exemption for biomass.
However, the articles that allowed for the exemption of the PIS/
PASEP tax on the transfer of steam and biomass for cogeneration
units, items included in the Provisional Measure 656 giving rise
to this Act, were vetoed by < f0> President Dilma Rousseff.
Without tax incentives, these energy sources will lose appeal in
the energy market since other renewable sources already receive
these government grants.
In terms of the tariff exemption for electricity transmission
(TUST and TUSD), there was a leveling between the different
sources like solar power, which had amortization ranging from
80 to 100 % and will now have amortization ranging from 50 to
100 %, as is the case with the Small Hydroelectric Power Plants
(SHPs). With this action all tariff exemptions of these sources
were leveled to those of the Small Hydroelectric Power Plants
(SHPs).
13
AGENDA/SCHEDULE
EVENTOS LIGADOS AO SETOR DE ENERGIA - 2015
FEVEREIRO
Mexico WindPower 2015
Data: 25/02/2015 a 26/02/2015
Local: Centro Banamex - Cidade do México – México
E-mail: [email protected]
Site: http://www.mexicowindpower.com.mx/
BioEnergy Italy 2015
Data: 25/02/2015 a 27/02/2015
Local: Itália
Site: http://www.bioenergyitaly.com
MARÇO
ICE Nuclear 2015; Developing the UK's Industry
Data: 25/03/2015
Local: Westminster, UK
Site: http://www.ice-conferences.com/ice-nuclear-2015/
11th Energy Efficiency and Renewable Energy Congress and
Exhibition for South-East Europe
Data: 11/03/2015 a 13/03/2015
Local: Sofia-Capital - Bulgária Site: http://www.eea.europa.eu/events/11th-energy-efficiencyrenewable-energy
2nd International e-Conference on Energies
Data: 16/03/2015 a 31/03/2015
Local: On-line
Site: http://www.sciforum.net/conference/ece-1/
ABRIL
Cenocon 2015
Data: 13/04/2015 a 14/04/2015
Local: Pestana São Paulo Hotel & Conference Center - São Paulo - SP
Site: http://www.rpmbrasil.com.br/index.aspx
Enase 2015
Data: 29/04/2015 a 30/04/2015
Local: Barcelona, Espanha
http://www.enase.org
JUNHO
InterSolar 2015
Data: 09/06/2015 a 10/06/2015
Local: München – Deutschland
Site: http://conference.intersolar.de
14
NEWS
II SRN – Seminário de Recursos Naturais, Sustentabilidade e
Tecnologias Ambientais
Data: 09/06/2015 a 12/06/2015
Local: Universidade Federal de Itajubá – UNIFEI/EXCEN
Site: http://www.cerpch.unifei.edu.br/semear
Feira Internacional de energias renováveis – All About energy
2015
Data: 10 a 12 de junho de 2015
Local: Fortaleza/CE
AGOSTO
12º COBEE - Congresso Brasileiro de Eficiência Energética
Data: 25 e 26 de agosto de 2015
Local: Centro de Convenções Frei Caneca - São Paulo – SP
Site: http://www.cobee.com.br
Fenasucro - 23ª Feira Internacional de Tecnologia
Sucroenergética
Data: 25 a 28 de agosto de 2015
Local: Sertãozinho - São Paulo – SP
Site: http://www.fenasucro.com.br/
SETEMBRO
Brazil Windpower 2015
1 a 3 de setembro de 2015
Rio de Janeiro – RJ
Intersolar South America
Data: 01 a 03 de setembro de 2015
Local: Expo Center Norte - São Paulo – SP
Site: http://www.intersolar.net.br/pt/intersolar-south-america.html
EU PVSEC
Data: 14 a 18 de setembro de 2015
Local: Hamburg - Deutschland
Site: http://www.photovoltaic-conference.com/
NOVEMBRO
ICEECE 2015: Conferência Internacional sobre Energia, Meio
Ambiente e Engenharia Química
Data: 12/11/2015 a 13/11/2015
Local: Tokyo, Japão
Site: http://www.waset.org/conference/2015/11/kyoto/ICEECE/call-forpapers
<Destaque>
Comitê Editorial
Editorial Committee
Presidente - President
Geraldo Lúcio Tiago Filho - CERPCH/UNIFEI
Editores Associados - Associated Publishers
Adair Matins - UNCOMA - Argentina
Alexander Gajic - University of Serbia
Alexandre Kepler Soares - UFMT
Ângelo Rezek - ISEE/UNIFEI
Antônio Brasil Jr. - UnB
Artur de Souza Moret - UNIR
Augusto Nelson Carvalho Viana - IRN/UNIFEI
Bernhard Pelikan - Bodenkultur Wien - Áustria
Carlos Barreira Martines - UFMG
Célio Bermann - IEE/USP
Edmar Luiz Fagundes de Almeira - UFRJ
Fernando Monteiro Figueiredo - UnB
Frederico Mauad - USP
Helder Queiroz Pinto Jr. - UFRJ
Jaime Espinoza - USM - Chile
José Carlos César Amorim - IME
Marcelo Marques - IPH/UFRGS
Marcos Aurélio V. de Freitas - COPPE/UFRJ
Maria Inês Nogueira Alvarenga - IRN/UNIFEI
Orlando Aníbal Audisio - UNCOMA - Argentina
Osvaldo Livio Soliano Pereira - UNIFACS
Regina Mambeli Barros - IRN/UNIFEI
Zulcy de Souza - LHPCH/UNIFEI
ONLINE UNIT MANAGEMENT FOR OPTIMAL OPERATION
OF HYDRO POWER PLANTS.........................................................................3
E.c. Bortoni, G.s. Bastos, B. Kawkabani
INDEX TEST AND BEST CAM CURVES DESIGN PROCEDURE
FOR KAPLAN TURBINES..............................................................................8
João Gomes P. Jr., Diego H. Kawasaka
HEAD LOSSES ANALYSIS IN SYMMETRICAL TRIFURCATIONS
OF PENSTOCKS - HIGH PRESSURE PIPELINE SYSTEMS CFD .....................
C. A. Aguirre, R. G. Ramirez Camacho
11
A FEASIBILITY STUDY ON THE USE OF WIND TUNNEL
EXPERIMENTS FOR HYDROKINETIC TURBINES ........................................ 15
M. M. Macias, R. C. F. Mendes, P. A. S. F. Silva, T. F. Oliveira, A. C. P. Brasil Junior
IAHR DIVISION I: HYDRAULICS
TECHNICAL COMMITTEE: HYDRAULIC MACHINERY AND SYSTEMS
Classificação Qualis/Capes
B5
B4
ENGENHARIAS I; III e IV
Biodiversidade
Interdisciplinar
Áreas de: Recursos Hídricos
Meio Ambiente
Energias Renováveis
e não Renováveis
ISSN 1676022-0
A revista está indexada no DOI sob o prefixo 10.14268
ISSN 1676-0220
9 771676 022009
00064
ARTIGOS TÉCNICOS
Comitê Diretor do CERPCH
Director Committee
CEMIG / FAPEPE / IEE-USP / FURNAS /
IME / ELETROBRAS / ANEEL / MME
TECHNICAL ARTICLES
Technical Articles Seccion
TECHNICAL ARTICLES
ONLINE UNIT M ANAGEMENT FOR OPTIMAL
OPERATION OF HYDRO POWER PLANTS
ONLINE UNIT MANAGEMENT FOR OPTIMAL
E.C. BORTONI, G.S. BASTOS,
2
B. KAWKABANI
1
ABSTRACT
The paper presents a novel methodology for the operation of those hydro power plants provided with a single penstock by the optimal
distribution of the dispatched power among its available generating units, aiming at the maximum efficiency of the whole power plant
energy conversion. While previous optimization methods made use of off-line static curve and parameters or expensive flow meters,
the proposed method is on-line in nature and uses a single pressure meter at the end of the power plant penstock. The method was
applied to a power plant and has resulted in a higher efficiency operation under several conditions.
KEYWORDS: Hydro power plants; energy; management.
1. INTRODUCTION
1.1 Classical economic dispatch
Hydro power plants have been used for electricity generation
for a long time due to its low operational cost, high energy
conversion efficiency, and because it uses a renewable primary
resource, the water. Nevertheless, water is an important resource
that must be handled with care, to ensure long term sustainability.
On the other hand, the self-sustainable development and the
reasonable exploration of natural resources have become the
great challenge of the 21st century. Hydro power plants deal with
these two sides of the coin. In Brazil, where hydro power plants
account for about 78% of the installed power and 92% of the
gross energy generation, every tenth of a percent increase in the
energy conversion efficiency is welcomed.
In the design of a hydro power plant the gross head is
defined by the regional topography and by the dam height. The
total power and the number of generating units is a function
of economic factors and of the hydrological availability of the
site. The flexibility of hydro power plants allows its operation to
accommodate both base and peak loads.
When meeting the peak load the generated power must
follow the load variations, therefore the loading and the number
of employed units of the power plant must be chosen to provide
the dispatched power with the highest efficiency. When supplying
the base load all the available units are operated to generate
their maximum power. Nevertheless, due to the hydrologic cycle,
there is a percentage of the year, the dry season, when there is
not sufficient water to push all the units of a power plant at their
rated power and, again the available units must be dispatched to
achieve the highest efficiency.
Few papers cover the subject of optimal operation of a single
hydro power plant (Arce et al., 2002), (Finardi and Silva, 2005),
(Bortoni et al., 2007), and (Cheng et al., 2009). The great majority
of published material regards to the hydro cascade operation,
aiming at the maximum energy generation for a given inflow
scenario such as (Pereira and Pinto, 1982) and (Carvalho, S.
Soares, 1987). This paper presents a novel methodology the online
optimal operation of hydro power plants for its best efficiency.
As long as the efficiency of each generating unit is a function
of the delivered power, the power plant optimization problem can
be stated as defining the output of each unit that maximizes the
total power generation efficiency or, in other words, to reach the
minimum generation cost subject to system constraints to meet
the demand and the capability of the machines. The simplest
economic dispatch formulation is
2. OPTIMAL POWER PLANT OPERATION
min CT (Pi)
s.t. ΣPi = Pd
(1)
PLi ≤ Pi ≤ PUi.
Notice that for hydropower plants, from now on, the cost function
is considered as the water consumption as a function of the generated
power, as long as the water has not a direct associated cost.
1.2 Dispatch based on efficiency tests
Unfortunately, it is well-known that each machine, even from
the same manufacturer and design, has its own characteristics
and the generation cost will eventually vary between like units.
Therefore, a procedure for optimal load distribution among the
available units of a power plant can start from the presented
equal load distribution criterion, as a quasi-optimal solution, to
perform an iterative process based on the efficiency curve of each
unit to obtain an overall maximum efficiency.
In this case, field tests must be done to obtain the efficiency
curve of each unit, which explains their efficiency behavior with
the dispatched power under several operating conditions of head
and flow.
Fig. 1 presents an example of an operating chart of a hydro
turbine model obtained from laboratory tests. The efficiency of
the hydro turbine depends on the turbine flow and net head,
leading to a three-dimensional diagram, which is the unit
efficiency characteristic for any load and head conditions.
Based on the knowledge of efficiency function of the units of a
hydro power plant, it is possible to obtain an optimal solution that
maximizes the efficiency of the entire power plant.
There are many methods that can be used to obtain an optimal
distribution of the dispatch power among the units of a power
plant. A brief description of such methods is presented as follows.
maxηT
s.t. ΣPi = Pd
PLi ≤ Pi ≤ PUi.
(2)
Universidade Federal de Itajubá, Brazil, e-mails: [email protected], [email protected]
École Polytechnique Fédérale de Lausanne, Switzerland, e-mails: [email protected]
1
1
HIDRO&HYDRO: PCH NOTÍCIAS & SHP NEWS, 64 (5), JAN,MAR/2015, DA PÁG. 3-7
3
ARTIGOS TÉCNICOS
With ηT given by:
Based on Figure 1 the net head is obtained as
(5)
(3)
Fig. 2: Dimensions for the net head calculation.
3. PROPOSED OPTIMAL POWER PLANT DISPATCH
Fig. 1: Operational chart of a hydro turbine.
Nevertheless, this efficiency curve is a single picture
of the machine behavior at a given moment and does not
consider eventual variations on the machine or on the power
plant parameters over time. Another approach based on loss
minimization rather than efficiency maximization can be applied
(Arce et al., 2002), but, again, the model parameters do not
depend on machine aging, temperature variation and other
factors.
1.3 Dispatch based on efficiency measurement
The energy conversion efficiency is obtained by the ratio
between the output and the input power. Equation (7) depicts
this concept by including the related variables.
(4)
The net head is the difference between the gross head
and the hydraulic losses. Therefore, a suitable device can be
conceived to determine the online efficiency of each unit based
or implemented using power plant SCADA. As long as the total
efficiency of the power plant depends on the efficiency of each
working unit (6), the optimization of the load distribution among
the available units can be accomplished according to (5).
4
The previous methods have been implemented and tested
for many years. While the first proposal is based on constant
efficiency behavior, the latter is based on online efficiency
measurement, which takes into account the aging of the units,
penstock losses, tailrace level, and other variables. Nevertheless,
the need for flow measurement constitutes a great drawback of
the previous approaches. Online or off-line flow measurement in
hydro power plants is a real challenge due to the large diameters
involved and the required accuracy.
Therefore, entire power plant efficiency optimization using
flow measurement criteria falls on the high cost of flow sensors
for such large diameters. In addition, occasionally the gain in
efficiency with the optimal operation is smaller than the accuracy
of the flow measurement, which leads to erroneous solutions.
It is proposed that the described problems can be overcome by
using a gauge pressure sensor at the end of the penstock, which
has much lower cost and more accurate than flow sensors.
The pressure at the penstock end is the difference between
the gross head and the head losses, which is proportional to the
squared flow. The following equation depicts this relationship.
p0 = z – k · Q2(6)
Equation (5) has a central importance in the adopted approach
as long as it gives an alternative way to infer the influence of the
flow without really measuring it. The static pressure at the end
of the penstock is the gross head, which is the vertical distance
from the forebay to the pressure metering point, minus the
friction losses obtained through the head loss coefficient.
One can conclude that the bigger the flow driven by the
turbines, the lower the pressure at the end of the penstock will
be. Therefore, maintaining the dispatched power met by the
power generated by the power plant units, a reduction of the
input flow means an increase in the overall power plant efficiency.
In other words, according to (6), this flow reduction is related
with a pressure increase. Therefore, instead of maximizing
the overall efficiency in order to obtain a global optimum, the
optimization problem can be rewritten to seek for the maximum
penstock end pressure:
TECHNICAL ARTICLES
max p0
s.t. ΣPi = Pd
PLi ≤ Pi ≤ PUi.
(7)
The proposed methodology is suitable for those power plants
with several units fed by a single penstock. The process starts
with all the units equally loaded to meet the demanded power.
Then, the loading of each unit is slightly changed until a maximum
penstock end pressure is achieved.
When applying this methodology the user does not have
access to the overall efficiency value, since the flow is not
measured. However, due to the concave characteristic of the
efficiency curves, it is recognized that the system will work in a
more economical way.
The search algorithm must have a heuristic capable to direct
the search engine to a power distribution between the available
units that lead to the highest pressure and overall efficiency.
Iteration is defined by a power step in the direction of the
maximum positive pressure variation.
The graphical results depicted in Fig. 4 exposes an interesting
feature of the proposed combinatorial optimization methodology,
i.e. the step changes when reaching the optimal solution, where
backward steps to a previous more efficient stage and a reduction
in the searching step as a function of an efficiency reduction, can
be perceived.
3.1 REAL TIME OPTIMIZATION
There are three important issues that must be taken into
account when selecting the optimization method to solve the
presented problem. The first is that the problem combinatorial
in nature, there are infinity combinations of generated power
among the available units that can meet the demanded power.
The second is that there is not a formal mathematical model
to be optimized, as long as updated efficiency curves of the
units are not known, but only the information of the pressure
at the penstock end. The third is that it is an online, real-time,
optimization problem, which must be solved as fast as possible,
maintaining the system stability.
The developed algorithm considers the search as a combinatorial
optimization problem (Nemhauser and Wolsey, 1998). The inputs
of the model are the delivered power of each unit and the gauge
pressure value at penstock end. The output is a signal to act as
a reference on each speed governor and the power of each unit.
Combinatorial optimization problems can be solved using
either exact methods (Nemhauser and Wolsey, 1998) or heuristics
(R. C. Holte, 2001). The exact methods explore large solution
space and are very time consuming, making them impractical for
real-time optimization applications. The use of heuristics is very
suitable for such cases, allowing for finding efficient solutions in
a very reasonable execution time instead of looking for the global
optimum (R. C. Holte, 2001).
The best solution search is made by applying combinations
of small pre-defined disturbance steps in the generated power of
each unit, keeping demanded power met, until the most efficient
operation point is found.
The example shown in Figure 3 represents a small power
plant with three units and has a demand of 15 MW. At time 0,
the demanded power is equally divided between the units, resulting
in certain penstock end pressure. At time 1, the unit #1 has its
power increased by one step, while unit #3 has its power reduced
by one step, thus keeping the overall generated power and leading
to a new pressure. By time 3, there is a new power distribution
with a new step power increase in unit #1 and a reduction of the
generated power of unit #2 by one step. The total generated power
is kept constant and meets the dispatched power, with some change
in the overall efficiency, described by the penstock end pressure.
Fig. 3: Guess-and-check process of the search engine.
Fig. 4: searching step change due to an efficiency reduction.
The time to complete one iteration is approximately the units
settling time multiplied by the number of possible combinations.
The settling time depends on the power plant arrangement,
which eventually will reflect the water acceleration time constant
and on speed governor time constants. In general settling time is
less than sixty seconds (Kundur, 1993).
4. APPLICATION
As the first assumption, the proposed methodology is suitable
for those power plants provided with a single penstock. Its
application to the Rio Bonito Hydro Power Plant was selected to
be explored here. This power plant has a single penstock feeding
three units of 7 MW each, totalizing 21 MW. The rated gross head
is 160 m and the rated flow is 15.6 m³/s.
For evaluation purposes, off-line efficiency tests were applied
to the three units in the wet and dry seasons of the year. Due to
the absence of rain during the dry season in relation to the wet
season, the gross head was reduced from to 158 m to 149 m. The
efficiency curves of the machines are shown in Figure 5 for units
#1, #2, and #3, respectively.
The difference in the efficiency of the units for different
gross heads is notorious, ranging from about 2 to more than
6 percentage points, reflecting the hydro turbine behavior
represented by its performance chart. Such phenomenon is very
difficult to model using algebraic formulations and can only be
detected by using either on-line efficiency measurement or an
observing variable.
A very high accuracy class smart pressure sensor was
installed at the penstock end. The digital transmission of the data
allowed for obtaining pressure measurements with resolution on
the order of millimeters of water column. For evaluation purposes, water flow was also measured with a
non-intrusive ultrasonic flow meter. Figure 6 shows the penstock
end pressure as a function of the water flow. Notice that the
curve shows a negative coefficient parabola as expected (5)
and that its abscissa intercept can vary according to the water
upstream level.
5
ARTIGOS TÉCNICOS
iterative process. A change of 500 kW is applied to the machines
at each iteration. The best combination was obtained with machine
#1 loaded with 6 MW and machine two with 4 MW. At this point
the pressure was 144.890 mH2O and the flow was 9.62 m³/s.
Figs. 7 and 8 presents these evolutions. The iterative process was
considered finished as long as no combination was found better
than the previous operating condition. A benefit of almost 1% was
reached with the water flow reduction, as show in Fig. 9.
4.2 Dispatch of 18 MW
(a)
All the units were participating of the dispatch of 18 MW. In the
beginning of the iterative process the load was equally divided by
the three units and each one was loaded with 6 MW. After applying
steps of 500 kW for each combination with the three available
units. In the third iteration no combination was found better than
the previous results, ending the iterative process, Fig. 12.
(b)
Fig. 7: Load distribution during the optimization process – 10 MW.
(c)
Fig. 5: Efficiency curves of units for different gross heads.
Fig. 6: Water flow rate as a function of penstock end pressure.
Fig. 8: Pressure and flow during the optimization process – 10 MW.
Fig. 9: Efficiency evolution during the optimization process – 10 MW.
Due to the very large time constant of the upstream water level,
it is considered constant during the optimization process. Optimal
load distribution among the three units of the power plant, employing
the proposed methodology, was carried out for dispatched powers
of 10 MW and 18 MW, for a gross head of 149 m.
4.1 Dispatch of 10 MW
In the first case, dispatch of 10 MW, units #1 and #2 were
selected to supply the load as long as each one is able to carry
7 MW. Each one was loaded with 5 MW at the beginning of the
6
Fig. 10: Load distribution during the optimization process = 18 MW.
TECHNICAL ARTICLES
In addition, considerable improvement on the presented
methodology can be obtained with the construction of a data
base of efficient solutions, which would allow starting the iterative
process from a quasi-optimal solution, reducing the number of
steps and iterations.
Therefore, future work includes, among others, the use
of reinforced learning techniques and the study of online load
distribution on those power plants provided with several penstocks.
6. NOMENCLATURE
Fig. 11: Pressure and flow during the optimization process – 18 MW.
Fig. 12: Efficiency evolution during the optimization process – 18 MW.
4.3 Analysis of the results
In both dispatch conditions the combinatorial loading of
the units was performed manually as a specific algorithm was
not implemented in the power plant SCADA system. It was
observed that the settling time was about thirty seconds for each
combination and, therefore, each iteration was performed in less
than five minutes. Considering a single step of 500 kW, the whole
optimization process took two iterations to reach an efficient
solution, i.e., less than ten minutes.
Benefits of 0.9% and 0.3% of the operational efficiency were
obtained with the application of the proposed methodology for
dispatching 10 MW and 18 MW respectively. Such reduction could
be expected because the greater the dispatched power the lower the
flexibility of operation will be. At the limit, when dispatching 21 MW,
the maximum output of the power plant, there is no flexibility, all the
units must work on their rated power, and there is no choice, no gain.
5. CONCLUSIONS
The work presented a novel methodology for the optimal
operation of hydro power plants provided with a single penstock,
leading to the optimal distribution of the dispatched power among
its available units.
As long as the flow is not measured, the efficiency of the
power plant cannot be determined. However, due to the concave
characteristic of the optimization function, the applied algorithm
will search for the highest gradient in each iteration and the
power plant will converge to its maximum efficiency.
The presented application, for example, demonstrated gains
that vary from zero, at full load operation, to 0.9% at half load. As
long as the water availability varies during the year, establishing
wet and dry seasons, the annual gain benefits can be assessed
by mathematically operating the flow duration curve of the site
under analysis with its gain-power curve.
C
P
ΣPi
η
ρ
g
Q
H
p0
z
k
P1
γ
D
a
y
cost function ($)
Subscripts
power (MW)
T total
summation of all units generation (MW) d dispatched
efficiency
i i-th unit, input
fluid density (kg/m³)
L lower
gravitational acceleration (m/s²)
U upper
turbine flow (m³/s)
o output
net head (m)
static pressure (m)
gross head (m)
head loss coefficient
pressure on the turbine input (N/m²)
specific weight of the water (N/m³)
the turbine input and output diameters (m)
fixed distance between the turbine input to a given reference (m)
variable distance from the reference to the downstream level (m)
7. REFERENCES
• A. Arce, T. Ohishi and S. Soares. Optimal dispatch of
generating units of the Itaipu hydroelectric plant. IEEE Trans.
on PWRS-17(1), Feb. 2002, pp. 154-158.
• E.C. Finardi, E.L. da Silva. Unit commitment of single
hydroelectric plant. Electric Power Systems Research 75
(2005) 116-123.
• E.C. Bortoni, G.S. Bastos, L.E. Souza. Optimal load distribution
between units in a power plant. ISA Transactions 46, 2007,
pp. 533–539.
• C. Cheng, S. Liao, Z. Tang, M. Zhao. Comparison of particle
swarm optimization and dynamic programming for large scale
hydro unit load dispatch, Energy Conversion and Management,
Vol. 50(12), Dec. 2009, pp. 3007-3014.
• M.V.F. Pereira, L.M.V.G. Pinto. Decomposition approach to the
economic dispatch of hydro-thermal systems. IEEE Trans. on
PAS-101(10), 1982, pp. 3851-386
• M.F. Carvalho, S. Soares. An efficient hydro-thermal scheduling
algorithm. IEEE Trans. on PWRS-2(3), 1987, pp. 537-542.
• G. L. Nemhauser, and L. A. Wolsey. Integer and combinatorial
optimization. Vol. 18. New York: Wiley, 1988.
• R. C. Holte, "Combinatorial auctions, knapsack problems,
and hill-climbing search." Advances in Artificial Intelligence.
Springer Berlin Heidelberg, 2001. 57-66.
• P. Kundur, Power System Stability and Control. EPRI Power
System Engineering Series. McGraw-Hill, Inc. New York, 1993.
ACKNOWLEDGMENTS
The first author would like to thank FAPEMIG, CAPES, CNPq,
FINEP, and INERGE for the support in conducting research.
7
ARTIGOS TÉCNICOS
INDEX TEST AND BEST CAM CURVES DESIGN
PROCEDURE FOR KAPLAN TURBINES
1
João Gomes P. Jr.,
Diego H. Kawasaka,
2
ABSTRACT
This paper presents in detail the methodology adopted by the Alstom’s Special Measurements Team to perform an Index Test and define
the best family of cam curves for its Kaplan turbines prototypes.
The new methodology takes into account on-site head loss measurements and the shape of the turbine model’s cam curves in order to
calculate a new family of cam curves for the prototype.
Finally, this new family of curves is implemented on Alstom’s speed governor so that the generating unit will be at its best efficiency at
any head.
KEYWORDS: Kaplan Turbines; market;high efficiency; measurements.
1. INTRODUCTION
2.1 Initial Verifications
Low head Kaplan and Bulb turbines have a very large market
potential in Brazil. Differently from Francis turbines, Kaplan and
Bulb turbines are double regulated, providing them high efficiency
over a broad range of head and discharge.
Nevertheless, their double regulation also means a more complex
system which requires a very precise combination of guide vanes and
blades positions in order to make sure these turbines are operating
with their best efficiency. These blade-to-vane combinations, known
as cam curves, are controlled by the speed governor as a function of
the power setpoint and the measured head.
The best cam curves are usually defined on reduced scaled
model tests. Those are then loaded on the speed governor’s
software of the prototype with the aim of reproducing the model
results and maximize efficiency. Although, there are many factors
that may decrease the prototype efficiency, such as:
• The theoretical head loss estimative can be imprecise or
different from the real loss due to modifications in the water
intake or outlet. As the speed governor uses information of
gross head, conversion from model test results using net
head values to gross head must be as accurate as possible;
• The head information sent to the prototype’s speed governor
can be incorrect;
• Non homologies between model and the prototype;
• Commissioning errors on the speed governor, creating differences
between the position set point indicated by the speed governor’s
software and the real position of the guide vanes;
• Damage or deterioration sustained from continuous use of the
equipment can also cause inaccuracies.
Most of the items above can be verified with an appropriate
procedure to perform an index test. This paper presents these
general procedures. In addition, as the index test is usually done
in a small range of the operational head range of the generating
unit, a detailed procedure to extrapolate cam curves to the
remaining range of heads is presented.
Some results obtained in units tested by the Alstom’s
measurements team are presented as examples.
Before performing the index test itself, it is recommended
to make some initial verifications. One very important test is
to verify if the head information sent to the speed governor is
correct.
There are usually two water level sensors, one upstream
the turbine at the water intake and another downstream the
turbine at the water outlet, that send these level measurements
to the supervisory system (SCADA). The SCADA calculates the
difference between those levels and sends this head information
to the speed governor. Hence, it is very important to verify that
these level measurements are correct. For that, one can measure
the pressure at the turbine inlet p1 and calculate the upstream
level H3 as given in eq.(1):
2. GENERAL PROCEDURES: INITIAL MEASUREMENTS
AND INDEX TEST
The index tests are usually required to follow the IEC 60041
standard (IEC:60041, 1991) procedures. On this chapter, some of
these procedures are detailed and some other procedures are added.
(1)
Where z_1 is the pressure sensor level measured in meters
above the sea level (masl). This level value must be as precise
as possible, normally using topographical indications. The gravity
g and the density ρ must be calculated as described in the IEC
60041 (IEC:60041, 1991).
Or, at the turbine outlet:
(2)
From Alstom’s experience, the calculated upstream H_3 or
downstream H_4 levels and the value indicated by the SCADA
must not have more than 10cm difference. This variation is
considered acceptable as there are measurements uncertainties
in every term of the equations above, and the head information
error will have a very small effect on the speed governor’s cam
curves.
Another very important verification that must be done
before performing the index test is to make sure that the angle
information of the blades and guide vanes indicated on the speed
governor is indeed the real angle on the machine. As these
information come from sensors and a mechanical system that
can be damaged or modified with time and use, this check must
be done from time to time.
Another very important check regarding the speed governor
itself is to certify that the error between the position setpoint of
the blades or vanes and the real position are in agreement. The
Alstom Hydro, Taubaté, Brazil,e-mail: [email protected]
Alstom Hydro, Taubaté, Brazil,e-mail: [email protected]
1
2
8
TECHNICAL ARTICLES
closed-loop feedback system may have a steady-state offset error.
The integrator part of the PID controller is meant to minimize this
error, but during the real operation of the unit the operational
error will depend on how the PID controller coefficients are set.
In other words, before starting the index test and the best
cam curve verifications, one must be sure that what is measured
and informed to the speed governor of a double regulated turbine
is indeed the real state of the machine. Otherwise, cam curves
implemented on the speed governor that are based on scaled
model results will not be effective.
2.2 Index Test and Cam Curve Verification
The index test and cam curve verification will generate results
such as the graph on figure 1. The procedure is: the blades are
fixed and the guide vanes position is varied, while measuring
efficiency for each combination. As the graph shows, there will
be a combination of blades and vanes position that will maximize
the unit’s efficiency. The general calculation and measurements
procedures are well described at the IEC standard.
Fig. 2: Example of head loss measurement as a function of the squared of
the discharge. The blue points are the measured values and the red line is a
tendency line of these points. The green line is the real head loss estimative.
3. GENERATING CAM CURVES FOR THE ENTIRE
OPERATIONAL RANGE
With the results obtained from one single index test, the
Alstom’s special measurements team adapted the procedure
proposed by Lee Sheldon (Sheldon, 2012) in order to extrapolate
the best cam curve obtained from an index test to a set of 5 cam
curves covering the whole operational range of the unit under test.
From the graph on figure 1, one can define a combination
of blades and guide vanes position that will maximize the unit’s
efficiency. For this unit, the result would be those represented
with the square dots on figure 3. On the figure 4, the variation
of gross head for these measured points is shown. Instead of the
value shown at the SCADA, the values presented were calculated
using the measured discharge and the real head loss estimative,
as described on item 1.3.
Fig. 1: Efficiency measurements in order to find the best combination of
blades and vanes position. The test is divided in steps where the blades
positions are fixed while the vanes opening are varied.
2.3 Head Loss
In addition to the efficiency, the index test can also provide a
good estimative of the head loss coefficient.
The net head Hn is calculated as given in the eq. (3):
(3)
The gross head HG is calculated as given in the eq. (4):
HG = H3 - H4
(4)
The head loss HL is then calculated:
HL = HG - Hn(5)
As discussed in 1.1, the upstream and downstream level
measurements H3 and H4 displayed at the SCADA usually have
an offset error if compared to the measurements done at the
turbine inlet and outlet, as described in equations (1) and (2). As
a consequence, the head loss calculated as in eq. (5) will not tend
to zero when the discharge approaches zero.
The figure 1 presents an example of head loss measurement.
It presents the head loss measurements as a function of the
square of the discharge. The red line is the tendency line of these
points and shows how the measurements usually do not move
towards zero due to the measurement errors explained before.
Consequently, the real head loss is expected to be closer to the
green line shown in the graph.
Fig. 3: Best combination of guide vanes angles and blade angles obtained
from the index test.
The next step requires information from the model test. Using
the model test hill chart, it is possible to draw lines of constant
blade opening as a function of the gross head (figure 5). Scale
model test results are usually given in net head values. The
conversion to gross head must also be done with the head loss
coefficient measured on-site.
The method presented on this paper is based on graphical
analysis and the idea of using scale model results is to visualize
how the guide vanes should open or close as the gross head
varies. Taking that in consideration, it is not important if there is a
small variation between the best blade position measured on the
scaled model test and the position measured on the prototype.
The idea is to keep the same shape of the curves found on the
model test in order to allow the extrapolation of the index test
results to the whole head range.
9
ARTIGOS TÉCNICOS
heads to cover the operational range of the unit. The graph on
figure 6 defines 5 constant heads for this example: 11, 11.5, 12,
12.5 and 13 meters of water column. The triangles on the graph
show the points where the constant blade angle curves cross
these heads.
As a result, 5 cam curves that will maximize the unit’s efficiency
on any head are defined. They are presented on Figure 7.
Fig. 4: Best measured guide vanes opening as a function of the measured
head.
The blue dots on figure 5 are the points where the constant
blade opening curves cross the lines connecting the points
measured on the index test. With the guide vanes opening values
of these points, it is possible to find the equivalent blades opening
on the graph of figure 3.
Fig. 7: 5 cam curves covering the whole operational range.
4. CONCLUSION
This paper presents some important steps that must be taken
in order to perform an accurate index test followed to a procedure
to extrapolate one single cam curve found on an index test to a
set of 5 cam curves, covering the entire operational range of the
unit.
The measurements results obtained in one power plant
in Brazil are presented. The resulting set of cam curves were
implemented on the unit’s speed governor and are performing
very well.
5. NOMENCLATURE
Fig. 5: Plotting constant blade opening curves as a function of the gross
head. Even though the shape of the curves is based on model test results,
the blades angles are defined on the prototype’s index test.
g
Acceleration due to gravity
HG Gross head
HL Head Loss
Hn Net head
p
Gauge pressure
QDischarge
υ
Mean flow velocity
zLevel
ρ
Density
Subscritps
1 High pressure reference
2 Low pressure reference
3 Water intake reference
4 Water outlet reference
6. REFERENCES
Fig. 6: Defining the blades angle and the vanes opening for 5 different heads.
The Alstom’s speed governors have 5 cam curves for 5
different heads. Those curves are interpolated in between these
10
• IEC:60041. (1991). International Standard: Field acceptance
tests to determine the hydraulic performance of hydraulic
turbines, storage pumps and pump turbines.
• Sheldon, L. (2012, March-April). Method to Delevop a Family
of Cam Curves from a Single Index Test. HRW - Hydro Review
Worldwide, pp. 40-45.
TECHNICAL ARTICLES
OF PENSTOCKS - HIGH PRESSURE PIPELINE SYSTEMS CFD
1
C. A. Aguirre,
R. G. Ramirez Camacho
2
ABSTRACT
Systems using trifurcations allows flow of water to provide several turbines operating at the same time. This arrangement presents
smaller assembly costs in comparison of independent pipeline systems. However this installation can generate high losses in the
system. This study focuses the quantified losses as a function of the volumetric flow rate, using computational fluid dynamics (CFD).
To determine the coefficient of losses were analyzed three mesh settings: hexahedral, tetrahedral and hybrid, considering steady state
flow. Based on the literature, the k-ω turbulence model, with refinement near wall elements, quantified the y plus. Results of loss
coefficients for different discretizations are presented in this paper.
KEYWORDS: trifurcation, numerical simulation, SST, head loss, mesh.
1. EVALUATION OF MEASUREMENT UNCERTAINTIES
The trifurcations are part of the architectural complex that
forms the hydroelectric plant, which together with others, parts
and equipment has the purpose to produce electricity using the
hydraulic potential existing in a damming or a river. Whereas
the optimal operating point of the pipeline systems, the losses
must be reduced to obtain the best operating condition, with
fields of stable flow. These conditions can be defined from
tests in preliminary models to obtain appropriate geometries,
with controlled load losses and variations of flow supplying the
turbines.
The analysis of head loss can be done in the laboratory or
with the use of tools of numerical simulation with the advantage
of analysis of the local flow with the real dimensions, allowing
easy generation and adaptation of geometries. Considering its
application, both approaches are complementary, meanings that
the numerical validation must necessarily represent qualitatively
or quantitatively, the experimental results.
A lot of researches have been accomplished, in order to
quantify the head losses in the pipeline systems of hydroelectric
plants, focusing the best possible performance.
Wanng Hua (1967) made an experimental analysis, with
several wyes configurations and manifolds (Figure 1). The effects
of roughness on the wall were not considered, once the pipe
surfaces were polished. The head losses in the dimensionless form
were quantified with relation to the average flow velocity in the
main pipe. Based on the one-dimensional energy equation results
were obtained using data acquisition systems such as; dynamic
pressure that is representative of the flow in a particular section
of pipe, the pressure reading using a catheter was inserted at a
position and height where the flow is irrotational and permanent.
Fig. 1: Component of the critical section of wyes and manifolds, top view.
Rk Malik and Paras Paudel (2009) did an analysis for a small
hydroelectric power plant of 3.2 MW, located in Kaski (Nepal).
The constraints due the available space and the position of the
turbines were considered for the design of the adduction system
of the trifurcation, several tests were made focusing the optimal
profile of trifurcation so the head losses are as low as possible.
The calculations of pressure losses were done using the energy
equation between the entrance and three exits simultaneously.
The turbulent and laminar regimes were analyzed using ANSYS
CFD-FLOTRAN. Besides a tetrahedral mesh was generate,
as shown in Figure 2. The boundary conditions were defined
considering at the entrance, the gauge inlet pressure of 177
mmH2O, and the speed between 3 and 4 m/s and the static
pressure at the outlet is equal to the local atmospheric pressure.
Fig. 2: Tetrahedral mesh of the trifurcation in the section of the flow
separation.
Changes in the geometry of the trifurcation were made to get
to a head loss of 0.42%. Hence twenty different configurations
of the trifurcations were tested, including mechanical stresses
analyses.
Sirajuddin Ahmed (1965) obtained results of the head
loss in laboratory using three conventional configurations of
the bifurcations in which was changed the angle between the
branches from 60° to 90°, and the angle of taper for both 60°.
Besides, the evaluations for two spherical bifurcations with angle
between the branches of 90° and with different sphere diameters
were checked.
During the tests, the field of turbulent flow with Reynolds
number between 5x105 and 3.75x105 and a maximum flow rate
of 0.92 cfs (0.03 m3/s) were defined. The head loss coefficients
for spherical bifurcations were higher than the bifurcations
taper, the values of the first is 0.44 related to the bifurcation
with the greater diameter sphere and 0.30 to the bifurcation with
the smaller diameter sphere. The loss coefficients for the taper
Instituto de Engenharia Mecânica, Universidade federal de Itajubá. Caixa Postal: 50 - CEP: 37500 903 - Itajubá – MG Brasil. Av. BPS 1303, Bairro Pinheirinho, e-mail: [email protected]
Instituto de Engenharia Mecânica, Universidade federal de Itajubá. Caixa Postal: 50 - CEP: 37500 903 - Itajubá – MG Brasil. Av. BPS 1303, Bairro Pinheirinho, e-mail: [email protected]
1
2
11
ARTIGOS TÉCNICOS
bifurcations are 0.16 for the 90° angle between the branches
and 0.08 to 0.088 for angles of 60°. These results are for a
symmetrical flow at the entrance of the bifurcation.
Buntić Ivana, Helmrich Thomas and Ruprecht Albert (2005)
presented a model of Very Large Eddy Simulations (VLES). This
model has an adaptive filter technique that separate the part of
the fluid resolved numerically and the modeled part (Figure 3).
The modeled parts use k-ε extended model of Chen and Kim. This
model VLES is applied to simulate flows with unstable vortices in
geometries where the turbulent flow cannot be performed with
the classical models of turbulence.
Equation of conservation of mass
(1)
The equation of conservation of momentum, considering the
steady flow and inertial system.
(2)
Generally the term of the turbulence and the viscous tensor
are grouped. Thus the overall or general tensor is represented by.
(3)
Fig. 3: Model Approach VLES
Moreover, this model tries to maintain the computational
efficiency of the Reynolds-Average Navier-Stokes (RANS) and
the potential for solving large turbulence structures of the Large
Eddy Simulation (LES). Although the model can be applied in
coarse meshes the simulation depends heavily on the modeling.
Additionally, Buntić Ivana, Helmrich Thomas and Ruprecht
Albert (2005) had performed the simulation of a spherical
trifurcation, Figure 4, which makes the distribution of water
from the adduction system of water until the turbines. The outer
branches present oscillations given by the vortices found in
the flow. The variations are not periodic of a branch to another
generating a high head loss.
The Reynolds tensor τt can be modeled appropriately using
the Boussinesq hypothesis presented in terms of turbulent
viscosity µt.
(4)
Where k is the kinetic energy and δij is the Kronecker delta
operator.
In this paper the turbulent viscosity is obtained using the SST
turbulence model that uses the hypothesis of Boussinesq.
3. METHODOLOGY
The geometry of the trifurcation used in the research was
provided by ALSTOM Figure 5. This model has 25 m wide, 7 m
high and 39 m long. The pipe diameter into the fluid inlet (water
20° C) is 4.5 m and on all outputs 3 m, and in the trifurcation the
approximate angle of the side branches are 60 degrees.
Fig. 4: Trifurcation - computational mesh.
2. MATHEMATICAL MODEL
Turbulent flows are characterized by transport of the large
quantities of mass and momentum scalar that floating in the time
and the space, not steady. The flow velocity and fluid properties
have random variations in different spectrum ranges.
2.1 Equations for turbulent flow
The ANSYS-CFX software uses the equations of Reynolds
(Reynolds Averaged Navier-Stokes RANS) to solve the problems
of turbulent flow. In this model all dependent variables, scalars
and vector are decomposed into a temporal average and a
fluctuating part, when these variables are introduced in the
conservation equation for not inertial systems results, as shown
following equations.
12
Fig. 5: General geometry of trifurcation.
Flow rates are measured within the range from 20 m3/s to
70 m3/s, which still shows a permanent flow. Considering the
dimensions and flow rates, the Reynolds number is approximately
2.014x10-7
As (Casartelli et al., 2010) and (Galarça et al., 2004), show
that with a high Reynolds number and a complex geometry, the
SST turbulence model can be applied, since this model can solve
the problems of the models k-ω and k-ε. Thus, in regions with
bends and nearby the wall is used the k-ω model, and regions
farther from the wall the k-ε model. The SST model based on
the k-ω considers the transport of turbulent shear stresses
and provides accurate flow predictions for cases with adverse
pressure gradients involving separation.
TECHNICAL ARTICLES
Moreover, the mesh generation requires the definition of the
value of refinement of elements near the walls which can be done
using an appropriated wall function “y”, Ariff (2009) shows how
can obtain this value associated with the minimum y+ that can
be applied to the problem and the turbulence model.
Casartelli (2010) defines the y+ range for adduction pipeline
of a turbine, working with the turbulence model k-ω SST are
between 200 and 500 because the model applies equations in the
boundary layer. Thereby, this case using the y+ of 300 defines
a minimum distance for the initial layer of the mesh equal to
1.95x10-3 m.
The present work adopts ICEM-CFD® for preprocessing and
generation of geometry and mesh. The geometry uses three
composite meshes of different geometric elements inside it
and near the surface. The main characteristics of the meshes
showed in Table 1 and in Figure 7. The first mesh is hexahedral
originated of approximately 400 blocs (Figure 6) with hexahedral
refinement and exponential growth near the walls. The second
mesh is composed of tetrahedrons and pyramids at the core and
with layers of prisms with linear growth on the walls. The third
mesh is composed of hexahedral and pyramids at the core and in
the walls prism with linear growth.
Table1: General characteristics of meshes.
Mesh
Number of elements
Mesh type
Hexahedral
7006388
Structured
Tetrahedral
4154711
Unstructured
Hexahedral core
2272218
Unstructured
Fig. 7: Cutting Plane and behavior of the surface layers of mesh refinement
for (a) hexahedral, (b) tetrahedral and (c) hybridize with hexahedral core.
With the range of mass flow rates, SST turbulence model
and mesh generated, the "solver" software ANSYS-CFX ® is
chosen for the numerical solution of the problem. The value of
convergence RMS (root mean square) is fixed at 1x10-4 according
to the values given by ANSYS CFX Solver theory guide (2012) for
engineering researches and the ten points to be evaluated inside
the range of volumetric flows are shown in Table 2. The boundary
conditions for the entrance and exit are respectively mass flow
and static pressure.
4. RESULTS
The velocity and pressure data obtained with the ANSYS-CFX
program are used to calculate the head loss of each branch of the
trifurcation, as shown by (Wang et al., 1967) who employs the
equation 5, based on the dynamic pressure of the main pipeline
for the calculation of the coefficient of head loss k.
(5)
Where pT(r,c,l), corresponds to the values of total pressure in
the branches, right, center and left, vinlet, is the reference flow
velocity at the entrance of the pipe.
Table 2: Coefficient of head losses of trifurcation given by the
numerical approach, considering meshes with hexahedral and
tetrahedral elements and hybrid mesh with hexahedral core.
Coefficient of head losses k
Volumetric
flow rate
Q [m3/s]
Fig. 6: Construction of blocs of hexahedral mesh isometric view (a), union
of the four pipes (b) and views of the blocs that make up the cross section
of the pipeline (c).
In the Figure 7 (a) shows the influence of mesh refinement
near the wall with the number of elements because the refinement
extends to the inside of the mesh where is not very useful, while
the unstructured grids (b) and (c) present refinement only in
the layers nearest to the surface reducing the number of mesh
elements.
Left branch
Center branch
Mesh
Mesh
Right branch
Mesh
Hexa
Tetra
Core
Hexa
Tetra
Core
Hexa
Tetra
Core
20
0.513
0.442
0.444
0.329
0.268
0.265
0.515
0.429
0.431
25
0.456
0.424
0.423
0.279
0.252
0.252
0.457
0.415
0.412
30
0.448
0.415
0.409
0.258
0.238
0.237
0.443
0.403
0.403
35
0.446
0.406
0.404
0.252
0.228
0.228
0.442
0.397
0.399
40
0.426
0.400
0.405
0.245
0.220
0.214
0.423
0.386
0.389
45
0.430
0.396
0.397
0.242
0.213
0.215
0.442
0.377
0.391
50
0.424
0.389
0.400
0.234
0.208
0.206
0.446
0.374
0.373
55
0.423
0.394
0.403
0.231
0.201
0.204
0.429
0.373
0.373
60
0.426
0.383
0.397
0.223
0.198
0.200
0.402
0.362
0.372
65
0.435
0.388
0.392
0.220
0.194
0.198
0.433
0.368
0.372
13
ARTIGOS TÉCNICOS
In Figure 8 a, b, c are represented the losses coefficients of
the three branches of the trifurcation as a function of volumetric
flow rate. Three mesh configurations were analyzed: hexahedral
(black line), tetrahedral with elements prismatic in the wall (blue
line) and hexahedral core (red line). In all Figures 8 a, b, c, the
analysis shows that the hexahedral mesh has higher values when
is compared to the unstructured meshes. More specifically, in the
Figures 8 a, b the hexahedral mesh has greater instability of
the loss coefficient, compared to unstructured meshes. However,
it shows that the unstructured meshes have similar behaviors,
especially in the relation to head loss on the central branch.
These figures show that the smaller loss values are close to
the nominal flow rate, 90 m3/s. However, the analysis around this
value requires an approach using transient models type URANS
or LES. In this range, considering the phenomenon in the steady
state, the desired value of convergence can be reached with SST
(RANS) model.
The central branch presents head loss coefficients smaller,
because only have change in the area of pipes due to the greater
effect of energy dissipation is associated with the viscous friction
at the wall, whereas the side branches have variation in crosssectional area and a strong change in the direction of flow
(secondary flow).
The trifurcation at the nominal condition, generally operates
with flow rates above 60 m3/s in the transient regimen where
the coefficients for the central and lateral branches are around
0.2 and 0.4 respectively (Figures 8 a, b, c). Mays et al. (1997)
recommends for symmetric trifurcations the value of 0.3 in the
loss coefficient, for the three branches.
Fig. 9: Streamlines along the trifurcation of the hexahedral mesh (a),
tetrahedral mesh (b) and hybridizes with hexahedral core mesh (c).
5. CONCLUSIONS
An analysis using Computational Fluid Dynamics CFD was
presented to determine the losses coefficients in adduction
systems of type "symmetric trifurcation". The geometry was
divided into structured and unstructured volumetric elements.
Additionally, other analysis was done in relation to the velocity
field, the trajectories of the streamlines checking variations when
using different discretizations. Apparently the hexahedral mesh
is more sensitive to quantify the head losses meanwhile the
unstructured meshes show similar behavior between them and
qualitatively with the hexahedral mesh. Therefore, it is necessary
that the results are validated comparing its results with reduced
model tests in specialized laboratories.
6. BIBLIOGRAPHY
Fig. 8: Head loss coefficients of the three meshes and left (a) right (b) and
central (c) branches.
The behavior of the streamlines given by the velocity field
show clear differences between structured and unstructured
mesh as show in Figure 9, where structured meshes capture a
formation and propagation of vortexes in the side branches larger
than structured mesh and the velocities along the streamlines
and the separation of the boundary layer are higher for the
hexahedral mesh.
The hexahedral mesh in all flow rates were studied always
reached the value of converge with fewer iterations than the
unstructured grids. The differences in the number of iterations are
between 50% and 70% less for the hexahedral mesh. Besides,
comparing these meshes in relation to the number of iterations,
the hexahedral mesh requires a minimal convergence value, but
the tetrahedral mesh converges faster.
14
• ANSYS, Inc. Southpointe, 2012, ANSYS CFX-Solver Theory
Guide, Canonsburg, PA, USA.
• Ariff M., Salim S. M., CHEAH S. C., 2009, Wall y+ approach for
dealing with turbulent flow over a surface mounted cube: part
1 – low Reynolds number, Seventh International Conference
on CFD in the Minerals and Process Industries CSIRO,
Melbourne, Australia.
• Buntić I., Helmrich T., Ruprecht A., 2005, Very large eddy simulation
for swirling flows with application in hydraulic machinery, Scientific
Bulletin of the Politehnica University of Timisoara Transactions on
Mechanics Special issue, Timisoara, Romania.
• Casartelli E., Ledergerber N., 2010, Aspects of the numerical
simulation for the flow in penstocks, IGHEM-2010, Roorkee. India.
• Galarça, M. M., 2004, Análise numérica para modelos de
turbulência κ-ω e SST/κ-ω para o escoamento de ar no
interior de uma lareira de pequeno porte, Programa de pósgraduação em Engenharia Mecânica – PROMEC, Universidade
Federal do Rio Grande do Sul – UFRGS.
• Mays L. W., 1997, Hydraulic design handbook, Editorial
McGraw-Hill Education, New York, USA.
• RK, M., Paras, P., 2009, Flow modeling of the first trifurcation
made in Nepal, Hydro Nepal, Kathmandu, Nepal.
• Sirajuddin A., 1965, Head loss in symmetrical bifurcations,
The University of British Columbia, Vancouver, Canada.
• Wang H., 1967, Head losses resulting from flow through wyes and
manifolds, The University of British Columbia, Vancouver, Canada.
ACKNOWLEDGMENT
The author acknowledges to ALSTOM Brasil Energia Transporte
for financial and technical support
TECHNICAL ARTICLES
EXPERIMENTS FOR HYDROKINETIC TURBINES
1
M. M. Macias,
R. C. F. Mendes, 2P. A. S. F. Silva,
2
T. F. Oliveira, 2A. C. P. Brasil Junior
2
ABSTRACT
An experimental methodology to assess the performance of axial hydrokinetic turbines, based in wind tunnel experiments, is presented
in the present paper. The goal is to propose an experimental approach using airflow and reduced scale models in order to evaluate a
real axial turbine running in water flow conditions. Scaling arguments had shown that it is possible to obtain dimensionless performance
parameter under a set of similarity conditions (geometrical, kinematical and dynamical) using air flow and, at last, to transpose the
model results to the prototype real scale in water flow. Experimental results for the power coefficient as a function of the tip speed
ratio are presented for a 1:23 model. The prototype is a three blade axial rotor hydrokinetic turbine, with 10m of diameter, designed
to produce 500 kW. The control of the rotation velocity of the rotor arises as a key element of the methodology. The experiments were
carried out in a wind tunnel facility for a range of undisturbed velocities between 6m/s and 15m/s. Comparisons with numerical results
from 3D RANS simulations are made to evaluate the limits of application of the methodology.
KEYWORDS: Hydrokinetic turbines, reduced (small) scale experiments, hydrodynamics of axial turbines..
1. INTRODUCTION
In reason of economic and populational growth, the
energy consumption has steadily increased. The projection for
consumption by the year 2030 is more than twice the amount
of energy consumed in 1980. This growth scenario leads to a
search for sources of clean and renewable energies with low
environmental impact (Kaygusuz and Güney, 2010).
The hydrokinetic energy is an emerging class of renewable
technology that is being widely recognized as a unique and
unconventional solution to the use of water resources (Khan,
Bhuyan, Quaicoe and Iqbal, 2009). The hydrokinetic energy
conversion process involves the use the kinetic energy contained
in any water flow, which may be the source of drive seas or
even the normal flow of a river. The term hydrokinetic turbine
is dedicated to hydraulic machines capable of converting kinetic
energy from rivers or ocean currents into electricity (Lula, Brazil,
Salomon, Walnut and Maruzewski-Gaud, 2006).
Different from one conventional hydroelectric power plant,
the process of using hydrokinetic energy does not require the
construction of a dam, it is only necessary a submerged turbine
capable of converting kinetic energy contained in the water
stream into shaft work able to activate the generator, allowing the
conversion into electricity. Thus one need not interfere with the
natural course of the river. However, the hydrokinetic system has
lower efficiency, limited to 59.3% of kinetic energy incident on the
turbine rotor (Betz, 1926).
There are few references in the technical literature on the
design and use of hydrokinetic turbines, and also the knowledge
available in this application area is restricted. Generally, this type
of turbine is derived from the wind turbines, since the operation
of both are similar.
This paper presents an experimental and numerical study
of a small scale hydrokinetic turbine tested in wind tunnel. The
prototype is a 10 meter diameter axial hydrokinetic turbine with
three blades, designed to use the remaining potential of a hydro
power plant and generate 500kW. The scaling factor between the
prototype and the model is 1:23. The study of the scale model
is important because the prototype is a complex machine, with
it one can predict phenomena that will occur during operation of
the turbine, thus avoiding possible failures. The study model is
also used to find the best conditions for prototype work.
For the construction and testing of a scale model is important to
follow the theory of similarity. This ensures that the prototype and the
model will have their similar characteristics, thus validating the test.
The similarity theory says that one machine will be similar to your
model only if they have the three possible types of homogeneities:
dimensional, kinematics and dynamics (White, 2011).
A prototype and a scale model are geometrically similar if
only all the dimensions of the body in three coordinates have
the same ratio of linear scale. The kinematic similarity requires
the prototype and the model have the same ratio of length
scale and time. The result is that the speed scale will be the
same for both. In flow machines, it is possible to association the
kinematic similarity with the triangles of velocities. To maintain
the similarity of triangles speed is necessary that the model
preserves the tip speed ratio from the prototype(λmodel = λprototype ).
The dynamic similarity exists when the model and the prototype
have the same reasons of scale length, time and strength. With
the dynamic homogeneity, it is possible to find a relation between
the potencies. This relationship can be presented by the power
coefficient (Cpmodel = Cpprototype) (White, 2011).
This paper presents a methodology for a scale model of
hydrokinetic turbine tested in wind tunnel. It is intended to find
the performance of the turbine through the curves of Cp versus
λ. The results will be compared with the numerical results of a 3D
RANS simulation.
2. EXPERIEMENTAL METHODOLOGY
2.1 Wind tunnel
The tests were conducted in an open loop wind tunnel from
the Laboratory of Fluid Mechanics, Department of Mechanical
Engineering, University of Brasilia (UNB). The dimensions of the
test section are 0,65x0,65 m and the tunnel extension is 10m .
The fan is located at the exit of the tunnel and is driven by an
electric motor of 40 hp, sucking air from the tunnel entrance to
the exit. The possible variation of the speed free flowing between
is 6 and 16 m/s. The boundary layer into the section test, where
Universidade de Brasília. Departamento de Engenharia Mecânica. Laboratório de Energia e Ambiente. 70910-900. Brasília, DF. BRAZIL, e-mail: [email protected]
Universidade de Brasília. Departamento de Engenharia Mecânica. Laboratório de Energia e Ambiente. 70910-900. Brasília, DF. BRAZIL.
1
2
15
ARTIGOS TÉCNICOS
the turbine is positioned, is of 20 mm and the level of turbulence
in the tunnel is less than 5%.
The wind speed is measured using a Pitot tube connected to
a manometer. The pitot tube is located 3.6 m from the tunnel
entrance and at 1.4 m from the model and in the middle of the
cross section. The model is placed in the test section of the
tunnel and at a distance of 5.0 m from the entrance center. The
experimental error in the measured flow velocity is estimated at
5%. In Fig.1 is shown an image of the turbine within the wind
tunnel during a test.
on the motor through a series of variable resistors. Maintaining
a constant flow speed for each speed of rotation of the torque
obtained from the model system was measured with the load cell.
The signals obtained by the rotation sensor and the load cell was
sent to the microcontroller Arduino for automation of the assay.
Fig. 2: Details of sensors
Fig. 1: Scale model into wind tunnel
To analyze the performance of the turbine curves λ versus Cp
and Cq are constructed versus λ, and the power coefficient Cp,
Cq torque coefficient λ and the ratio of blade tip speed. These are
determined by eq. (1), (2) and (3). The speed ratio is the speed
ratio between the farthest point on the rotor blade and the speed
of free-flowing.
2.2 Scale model
The model hydrokinetic turbine was built with a scale factor
1:23 using the same geometric details of the prototype. The
model has diameter 520 mm and dimensions of the rest remains
the same scale factor. The turbine is of the horizontal axis type
rotor with three blades. The profiles of the vanes are NACA type
65(3)618. The model was built from aluminum using a CNC
machine three axes.
The rotor blades are attached directly to the shaft of a DC
permanent magnet motor Electro-Craft 110W. To apply load on
the rotor, a DC motor was connect in the shaft working as a brake.
The electric motor is integrated in a circuit of variable resistors,
working as a brake and as a variable load that can control the
rotational speed of the turbine. The motor is supported on two ball
bearings set in such structure that supports the turbine system.
Therefore, the brake balance was in order to measure the torque of
the system directly from a load cell. The load cell was constructed
with a digital scale SensorDisc SF-400. The transmission of force
between the brake and the balance is carried by an arm fixed to the
metal brake, as can be seen in Fig.2. Load cell was calibrated using
a system known weights. The torque is calculated as the product
of the force measured in the load times the distance from the cell
axis by the end of the arm. The typical error in the measurement
of torque is less than 0.01 N cm.
The rotation speed of the rotor is measured with an inductive
speed sensor SCHMERSAL IFL3B-10E-8M. The rotation sensor
was used measuring the rotational frequency of the shaft turbine.
This sensor was calibrated using an oscilloscope.
The data acquisition was performed using the open source
microcontroller Arduino Leonardo. The circuits of the sensors were
integrated on a single card and controlled via the Arduino board.
The tests of the reduced model were performed for different
free flow speeds. Wind speeds were adjusted values 13,14
e 15 m/s. These speeds were measured by the Pitot tube and
manometer. For each average flow velocity of the rotational
speed of the turbine is controlled and gauged with the inductive
rotation sensor. Speed control is accomplished by applying load
16
(1)
(2)
(3)
In the above equations, P is the power in the brake shaft, E_0
is the energy contained in the flow area of the turbine housing
(hydrokinetic power from the free stream), ρ is the density of air
and A = (πr2)⁄2 corresponds to the area perpendicular to the flow
of the turbine inlet section. The angular velocity ω is the rotor
radius is r and U∞ is the speed of free-flowing. The shaft power
can be determined by:
P = τ ω
(4)
where τ is the torque on the shaft which is determined by the
product of the force measured by the load cell times the size of
the arm.
3. NUMERICAL CALCULATION
The three-dimensional model was generated on SOLIDWORKS
software based on the design characteristics of the reduced
model. The software used for generating numerical grid was
ANSYS ICEM CFD. The computational domain was divided into
two parts: an inner, rotatable, with high density of elements
and an outer stationary with low density elements. The rotating
field is shaped like a cylinder 0.3 meters radius and 0.1 meters
long. Already the stationary domain is shaped like a cube, which
contains the rotating field with the approximate dimensions of
the wind tunnel with section 0.65 meters tall and wide and 2 feet
deep in the face of affluence and 6 meters downstream as can be
observed in Fig. 3.
TECHNICAL ARTICLES
Fig. 3: Numerical domain
The numerical grid generated showed 2.51 x 106 us, with
great refinement in the region close to the wall next regions. The
turbulence model used in this modeling was the SST, known for
showing good results for both laminar flow sublayer as in free
stream. To this end, the treatment was made close to the wall so
that the values of y + 2 are smaller than Another important factor
is the mesh refinement near the mat due to the high velocity
gradient in this region as illustrated in Fig.4.
In Fig.6 the power coefficient for various velocities of free
flow is presented. It can be seen that the maximum value of Cp
is around 0.11 and is obtained for λ = 3.8 and a free-flow speed
of 13 m/s. For speeds 14:15 m / s the maximum value of Cp is
at λ = 3.2. All experimental curves were fitted by a third-order
polynomial.
In Fig.7 the coefficient of torque for various free flow speeds
is presented. It can be seen that the maximum value is obtained
Cq for λ = 2.9 and a free-flow speed of 13 m/s. For speeds 14:15
m / s the maximum value of Cp is at λ = 2.6.
Fig. 4: Numerical mesh
The mesh is imported into CFX and then the boundary
conditions are applied in the computational domain as shown
in Fig 5 Attempted to perform with maximum fidelity of the
experiment in wind tunnel.
• Input speed: is a Dirichlet boundary condition, which is
attributed to the constant fluid velocity and normal to face
with turbulence intensity of 5%, according to the experimental
conditions. Already the pressure is determined so as to satisfy
the equations of motion.
• Outlet pressure: the downstream face a condition of Dirichlet,
which defined the boundary condition as the atmospheric
pressure (101325 Pa) and consequently the velocity field is
determined by the equation of motion was applied.
• No Slip: was imposed on all solid components of the rotor, this
means that the relative velocity of the fluid particle in the wall
to the wall is zero.
• Free slip: was imposed on the walls of the tunnel, so that does
not influence the flow. Thus, the shear stress between the
tunnel wall and the fluid is zero.
• Interface: The internal surfaces defining the cylindrical rotary
connection between the subdomain that contains the rotor
and the stationary field, have been linked, the condition of
frozen rotor ("rotor Frozen"). Thus the components of the
fixed domain are transformed into a moving reference system,
adding the Coriolis and centrifugal acceleration, enabling local
flow characteristics are transported through the interface.
Fig. 5: Contour conditions
4. RESULTS AND DISCUSSIONS
The rotor performance was evaluated for three speeds of
the wind tunnel: 13; 14:15 m / s. For each speed, the brake
applied was varied and the torque and speed mesurados rotation,
allowing the calculation of the coefficient of power and coefficient
of torque. Cp and Cq versus λ versus λ curves are shown in
Figures below.
Fig. 6: Experimental curve: Cp x lambda
Fig. 7: Experimental curve: Cq x lambda
The Fig.8 shows the comparison of the experimental and
numerical case for the speed of 13m / s tunnel.
How widely studied in the literature, in studies such as
Muljadi et al. (1999) and Burton et al. (2001), the variation of
the pitch angle is a direct effect on the power converted by the
turbine. The manual assembly process and the small size of the
model contribute significantly to the occurrence of unwanted
pitch angles, since this displacement of about 0.17 mm in the
positioning of the blade axis represents a one degree change
in pitch angle. Thus, it is believed that the discrepancies found
between the numerical and experimental results shown in Fig. 8
is related to incorrect assembly or even the instrumental error in
the manufacturing process of the blade, which are ignored in the
numerical modeling. However this uncertainty still needs further
investigation in metrological and numerical studies.
17
ARTIGOS TÉCNICOS
the prototype show significant differences in the values of power
coefficient for similar values of λ While the similarity in the values
of λ, which ensure proportionality in the forces acting on the
blade, the Reynolds number the prototype comes to submit two
orders of magnitude greater than the reduced model magnitude,
being reduced in 4x105 and 2.2 x 106 in the prototype model.
This difference has a major influence on the flow dynamics, which
in turn interferes with the power values.
5. CONCLUSIONS
Fig. 8: Numerical and experimental points for 13 m/s
The t of the maximum power value of 0.11 was obtained
for the experimentally reduced to a free-flow speed of 13 m / s
model. The speed ratio corresponding to peak power coefficient
is around the value of 3.8.
The experimental results of this study allow to obtain the
characteristics of the reduced model of hydrokinetic turbines
in various operating conditions. For translating the results of
the model to the prototype further investigation due to the
large difference in Reynolds number, thus having a hard time
to transpose results is necessary. Besides deepening the errors
involved in assembling the experimental test.
6. NOMENCLATURE
A
Rotor area
[m2]
Cp Coefficient of potency
Cq Coefficient of torque
E0 Hydrokinetic potency
[W]
P
Potency[W]
r
Rotor radius
[m]
U∞ Flow velocity
[m/s]
λ
Tip speed ratio
ρ
Specific mass
[kg/m3]
τ
Torque
[N.m]
ω
Rotational speed
[rad/s]
7. REFERENCES
Fig. 9: difference of power caused by the angle of the blade. (Burton et
al., 2001)
Fig. 10: Numerical comparison between prototype and scale model
Applying a method similar to the scale model, the prototype
of hydrokinetic turbines have been numerically simulated in real
scale to a wide range of values of λ as shown in Fig. \ Ref {}
prototype. We note that the reduced model in air and water in
18
• A. Betz. Wind energy und ihre ausnutzung durch windmuehlen. 1926.
• Tony Burton, David Sharpe, Nick Jenkins, and Ervin Bossanyi.
Wind energy handbook. 2001.
• M. Güney and K. Kaygusuz. Hydrokinetic energy conversion
systems: A technology status review. Renewable and
Sustainable Energy Reviews, pages 2996–3004, 2010.
• M.J. Khan, G. Bhuyan, M.T. Iqbal, and J.E. Quaicoe. Hydrokinetic
energy conversion systems and assessment of horizontal and
vertical axis turbines for river and tidal applications:A technology
status review. Applied Energy, 86(10):1823 – 1835, 2009.
• Flavio A.C.M. Lula, Antonio C. P. Brasil Junior, Lucio B.R.
Salomon, Ricardo Noguera, and Pierre Maruzewski-Gaud.
Experimental study of a new design of hydrokinetic turbine.IV
Congreso Nacional de Engenharia Mecânica, 2006.
• João P. Monteiro, Miguel R. Silvestre, Hugh Piggott, and
Jorge C. André. Wind tunnel testing of a horizontal axis wind
turbine rotor and comparison with simulations from two blade
element momentum codes. Journal of Wind Engineering and
Industrial Aerodynamics, 123, Part A(0):99 – 106, 2013.
• E. Muljadi and C.P. Butterfield. Pitch-controlled variable-speed
wind turbine generation,.1999.
• Fernada M. Souza, Thiago F. Oliveira, and Antonio C.P.Brasil
Junior. Estudo experimental de um modelo reduzido de turbina
hidrocinética. 16º POSMEC. Simpósio de Pós-Graduação em
Engenharia Mecânica, 2006.
• F. M. White. Mecânica dos fluidos. 6º edition, 2011.
TECHNICAL ARTICLES
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TECHNICAL ARTICLES
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parênteses, quando o autor fizer parte do texto. Quando o autor
não fizer parte do texto, colocar, entre parênteses, o sobrenome,
em maiúsculas, seguido do ano separado por vírgula.
O resumo deverá ser do tipo indicativo, expondo os pontos
relevantes do texto relacionados com os objetivos, a metodologia,
os resultados e as conclusões, devendo ser compostos de uma
sequência corrente de frases e conter, no máximo, 250 palavras.
Para submeter um artigo para a Revista PCH Notícias & SHP
News o(os) autor(es) deverão entrar no site www.cerpch.unifei.
edu.br/submeterartigo.
Serão aceitos artigos em português, inglês e espanhol. No
caso das línguas estrangeiras, será necessária a declaração de
revisão linguística de um especialista.
Segunda Etapa (exigida para publicação)
The manuscript should be submitted with following format:
should be typed in Times New Roman; 12 font size; 1.5 spaced
lines; standard A4 paper (210 x 297 mm), side margins 2.5 cm
wide; and not exceed 16 pages, including tables and figures.
In the first page should contain the title of paper, Abstract
and Keywords. The tables and figures should be numbered consecutively in Arabic numerals, which should be indicated in the
text and annexed at the end of the paper. Figure legends should
be written immediately below each figure preceded by the word
Figure and numbered consecutively. The table titles should be
written above each table and preceded by the word Table followed by their consecutive number. Figures should present the
data source (Source) above the legend, on the right side and no
full stop; and tables, below with full stop.
The manuscript in PORTUGUESE should be assembled in the
following order: TÍTULO in Portuguese, RESUMO (followed by
Palavras-chave), TITLE in English; ABSTRACT in English (followed by keywords); 1. INTRODUÇÃO (including references);
2. MATERIAL E MÉTODOS; 3. RESULTADOS E DISCUSSÃO; 4.
CONCLUSÃO (if the list of conclusions is relatively short, to the
point of not requiring a specific chapter, it can end the previous
chapter); 5. AGRADECIMENTOS (if it is the case); and 6. REFERÊNCIAS, aligned to the left.
The article in ENGLISH should be assembled in the following order: TITLE in English; ABSTRACT in English (followed by
keywords); TITLE in Portuguese; ABSTRACT in Portuguese (followed by keywords); 1. INTRODUCTION (including references);
2. MATERIAL AND METHODS; 3. RESULTS AND DISCUSSION;
4. CONCLUSIONS (if the list of conclusions is relatively short,
to the point of not requiring a specific chapter, it can end the
previous chapter); 5. ACKNOWLEDGEMENTS (if it is the case);
and 6. REFERENCES.
The article in SPANISH should be assembled in the following order: TÍTULO in Spanish; RESUMEN (following by Palabrallave), TITLE of the article in Portuguese, ABSTRACT in Portuguese (followed by keywords); 1. INTRODUCCTIÓN (including
references); 2. MATERIALES Y MÉTODOS; 3. RESULTADOS Y
DISCUSIÓNES; 4. CONCLUSIONES (if the list of conclusions is
relatively short, to the point of not requiring a specific chapter, it
can end the previous chapter); 5.RECONOCIMIENTO (if it is the
case); and 6. REFERENCIAS BIBLIOGRÁFICAS.
The section headings, when necessary, should be written
with the first letter capitalized, preceded of two Arabic numerals
placed at the beginning of the paragraph.
References cited in the text should include the author’s
last name, only with the first letter capitalized, and the year
in parentheses, when the author is part of the text. When the
author is not part of the text, include the last name in capital
letters followed by the year separated by comma, all in parentheses.
Abstracts should be concise and informative, presenting the
key points of the text related with the objectives, methodology,
results and conclusions; it should be written in a sequence of
sentences and must not exceed 250 words.
For paper submission, the author(s) should access the online
submission Web site www.cerpch.unifei.edu.br/submeterartigo
(submit paper).
The Magazine PCH Notícias & SHP News accepts papers in Portuguese, En-glish and Spanish. Papers in foreign languages will be
requested a declaration of a specialist in language revision.
Second Step (required for publication)
O artigo depois de analisado pelos editores, poderá ser
devolvido ao(s) autor(es) para adequações às normas da Revista
ou simplesmente negado por falta de mérito ou perfil. Quando
aprovado pelos editores, o artigo será encaminhado para três
revisores, que emitirão seu parecer científico. Caberá ao(s)
autor(es) atender às sugestões e recomendações dos revisores;
caso não possa(m) atender na sua totalidade, deverá(ão)
justificar ao Comitê Editorial da Revista.
After the manuscript has been reviewed by the editors, it is
either returned to the author(s) for adaptations to the Journal
guidelines, or rejected because of the lack of scientific merit and
suitability for the journal. If it is judged as acceptable by the
editors, the paper will be directed to three reviewers to state
their scientific opinion. Author(s) are requested to meet the reviewers, suggestions and recommendations; if this is not totally
possible, they are requested to justify it to the Editorial Board.
Obs.: Os artigos que não se enquadram nas normas acima
descritas, na sua totalidade ou em parte, serão devolvidos e
perderão a prioridade da ordem sequencial de apresentação.
Obs.: Papers that fail to meet totally or partially the guidelines above described will be returned and lose the priority of the
sequential order of presentation.

- cerpch

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