Análise do impacto da geração distribuída sobre a rede elétrica de distribuição devido à utilização de geradores fotovoltaicos

Abstract

Alternative sources of energy and distributed generation (DG) are current subjects, especially in Brazil where the regulations had just changed and now the possibility of DG and compensation of energy can be considered. The use of solar energy has been increased along the last years, thus as a heat source or as photovoltaic (PV) generation, based mainly on the low environmental impact of this energy source. This essay aims to study the impact of distributed generation in the electrical energy distribution system caused by the use of photovoltaic generators connected straight to the distribution grid. The study is done in steady state condition, in a specific feeder, considering typical curves proposed for sunny and cloudy days. A data base of irradiance and temperature of air ambient of one year had been used for this analysis. The data had been collected in the city of Porto Alegre – RS – Brazil, from July 2004 to June 2005. This data base was used to establish the generation typical curves of sunny and cloudy days through a methodology developed. The photovoltaic generation standards for sunny and cloud days had been defined by the use of these typical curves. With these standards were possible to analysis the impact in a specific feeder, located in the city of Viamão – RS – Brazil. The analysis of the impact in the grid considered the influence of distributed generation could cause on voltage levels at different bars along the feeder. It had been considered a penetration of DG of 20%, in two different hourly times for each day, sunny and cloudy typical curves. The power generated had been normalized related to the power consumed in different points of the feeder. The impact observed in the distribution grid is not relevant. However, the distribution generation did contribute to slightly raise some voltage levels that are already among the critical zone, in some of the sets analysed.