Since the early 1980s, wind power technology has experienced an immense growth with respect to both the turbine size and market share. As the demand for large-scale wind turbines and lor operation & maintenance cost continues to raise, the interest on condition monitoring system has increased rapidly. The main components of wind turbines are the focus of all CMS since they frequently cause high repair costs and equipment downtime. However, vast quantities of their failures are caused due to a bearing failure. Therefore, bearing condition monitoring becomes crucial. This paper aims at providing a state-of-the-art review on wind turbine bearing condition monitoring techniques such as acoustic measurement, electrical effects monitoring, power quality, temperature monitoring, wear debris analysis and vibration analysis. Furthermore, this paper will present a literature review and discuss several technical, financial and operational challenges from the purchase of the CMS to the wind farm monitoring stage.

A review of wind turbine bearing condition monitoring: State of the art and challenges

Hydropower is the backbone of the Brazilian electricity generation sector. Even though the use of this resource is advantaged in terms of greenhouse gas emissions, last years׳ severe droughts have exposed the country׳s huge dependency on hydroelectricity. Brazil׳s electricity supply system has shown to be vulnerable to electricity shortages and has demanded significant overhaul in order to address its challenges. The present paper provides a comprehensive review of the current status of the Brazilian electricity sector and discusses diversification of electricity generation mix as a strategy to improve electricity supply security in the country. An overview of the main features of the energy sources applied in Brazil is also presented through a review of the latest available generation data. The central section of this work is a discussion of the main causes of the current crisis and the future role of renewable energy sources in a 10-year perspective.

Electricity supply security and the future role of renewable energy sources in Brazil

Energy production from renewable sources is already a reality in many countries, and with that, different strategies for incentivizing investments in renewable energy generation have been proposed and used over the years. In this study, long-term policies that have been applied in several countries, such as feed-in tariffs, shares with commercialization of certificates, auctions, and net metering, are overviewed and discussed. The main advantages and disadvantages of these incentive strategies are emphasized, focusing on applications. Some of these strategies that have already been applied in Brazil are analyzed in greater depth, emphasizing the potentialities and fragilities of these mechanisms observed within the country. Even though it is a country that stands out in relation to other Latin American countries regarding electricity generation from non-hydro renewable sources, Brazil still faces barriers that prevent a utilization compatible with its potential. Moreover, the trend for renewable sources, such as wind and solar power, is to represent an energy capacity reserve to cover hydrological risks and also to contribute to a distributed generation spread through electricity distribution networks.

An overview of incentive policies for the expansion of renewable energy generation in electricity power systems and the Brazilian experience

Brazil's wind energy program is a successful public-private sector response to an electricity supply crisis in 2001 that created an attractive target for investors in renewable power. But evidence is accumulating that environmental impacts, which lead to territorial conflicts, livelihood erosion, and political responses, contradict sustainability claims of wind power development. We synthesize conflicts emerging in coastal Ceara state, a pioneer in Brazil's rapid development of wind power. Environmental impacts caused by wind farms, which locate on dune fields and other coastal systems, create conflicts by denying traditional communities access to resources that sustain livelihoods and cultural identities. Resource-access conflicts produce political responses that seek mitigation measures, but may escalate into a wider political challenge to continued development of wind power. We highlight the importance of land-tenure policies to assure the territorial integrity of traditional communities in areas targeted for wind power implementation. Analysis of conflicts supports suggested solutions for governments, firms, and traditional communities that may be applied in other developing countries and may help investors and planners avoid future conflicts.

Is Brazilian wind power development sustainable? Insights from a review of conflicts in Ceará state☆

This paper aims to present a review of the increasing contribution of wind power to the Brazilian electric matrix and an analysis of the main impact on technical, political and social aspects. This work takes into account the state-of-art of the wind power technology, the wind resource potential and the evolution of installed capacity in the country. The institutional programs and the fiscal incentives provided by the Brazilian government are also discussed in this paper, including its impacts on the society. We have reviewed national and international reports and relevant scientific papers to realize this work. The analysis shows that electric crisis in 2001 led the Brazilian government to develop new energy policies that supported the rapid growth of the wind industry from imported technology. Later on in the year 2004, the government mandated that the technology be developed within the country. It is expected that from 2011 (of approximately 1500 MW) until 2021 the installed wind capacity would increase by a factor of 600%. However, the national technology acquisition and development is still incipient. It is important to produce locally wind turbine components and is highly desirable to increase collaboration between industries and universities in the country.

Development of the wind power in Brazil: Political, social and technical issues

The Itamaraca island close to the state of Pernambuco in Brazil receives thousands of visitors during the period of long summer vacations (3 months), increasing the peak demand by a factor of almost 200%. The purpose of this work is to demonstrate that the offshore wind turbines can meet peak energy demand and at the same time reduce impact on conventional energy generation during other months as well. The method involves a nautical wind map at a height of 10 m, and extrapolating it for the desired height by logarithmic law. The annual wind energy output employs Weibull probability density function. The wind turbine siting is chosen with the aid of the nautical chart. The results obtained demonstrate that three wind turbines would generate about 30,000 MWh per year, sufficient for meeting electricity demand in the island.

Meeting Peak Load Demand by an Offshore Wind Farm in Brazil

Analysis of design parameters of large-sized wind turbines by non-dimensional model

Análise das atuais políticas de incentivo à mini e microgeração distribuída e da certificação de aerogeradores de pequeno porte no brasil

This workmodels capacity factor in terms of wind turbine operating characteristics, mean wind speed, and shape parameter of Weibull probability density function. The methodology used involves fewer parameters than have been used by other workers. We have used a nondimensional speed parameter (x) as the ratio of the wind speed (V) to the mean wind speed (Vm). The operating characteritics of a megawatt wind turbine cut-in (Vin), rated (Vr) and cut-out (Vout) speeds are divided by Vm, resulting into nondimensional speeds: xin, xr, and xout, respectively. Similarly, the Weibull scale parameter is also transformed by the Vm. The final model of the capacity factor constitutes four variables: xin, xr, xout and k. The analysis of model shows that, in general, low values of nondimensional speed xr results into higher values of capacity factor. The shape parameter also influences the value of capacity factor. High values of shape parameter provides, in general, low value of capacity factor. For example, a turbine d...

Oyama Douglas Queiroz de Oliveira Filho

Papers

Development of the wind power in Brazil: Political, social and technical issues

Meeting Peak Load Demand by an Offshore Wind Farm in Brazil

Analysis of design parameters of large-sized wind turbines by non-dimensional model

Análise das atuais políticas de incentivo à mini e microgeração distribuída e da certificação de aerogeradores de pequeno porte no brasil

Defining Capacity Factor by Weibull Shape Parameter and Mean Wind Speed