quinta-feira, 13 de novembro de 2014
Making isolated renewable energy systems more reliable Luiz A. de S. Ribeiro , Osvaldo R. Saavedra, Shigeaki, José G. de Matos, Guilherme Bonan Electrical Energy Institute, Federal University of Maranhão, São Luís, MA, Brazil R&D Department, CP Eletrônica S.A, Porto Alegre, RS, Brazil
Introduction The supply of electricity to isolated communities in Brazil and other developing countries, in general, is still done in a precarious way, using diesel generators, which operate for 3e4 h a day [1,2]. This has happened mostly due to the high cost associated with the expansion of the conventional power grid to these communities. In some cases, technical and environmental constraints also have been factors that have prevented the full electrical service in these communities, especially those located on oceanic islands. For societies to have or attempt to maintain a sustainable development it is necessary a lot of effort in the discovery and use of renewable energy sources as well as in the increase of the efficiency in the processing of use these energy sources. In this aspect, the electric power generation based on solar photovoltaic and wind turbines technologies has been effective in distributed generation systems and also in standalone systems for supplying isolated communities [3,4]. In standalone systems, those solutions have been shown appropriate for areas of difficult access, dispersed, with environmental restrictions or with a population formed by low-income people, even when these adverse characteristics represent a difficulty for the sustainability of the designed generation system. Technical and operational troubles, and supply interruptions are difficult to be solved due to the non availability of technical assistance. The delay of remote assistance leads to long periods of lack of electrical service, causing loss of credibility in this kind of system [5,6]. Thus, to overcome these difficulties, isolated systems must be projected taking into account reliability, minimizing the dependence of maintenance and human intervention, mainly because it is expensive and quite often not available.