Proteção contra sobrecorrentes em redes de distribuição aéreas de 13,8kV: análise do desempenho do sistema atual e propostas para melhorias

Abstract

The quality and continuity of electricity supply to customers and safety of workers and general population depend on the overcurrent protection studies of distribution networks. The faults severely affect the quality of the electrical system, for this reason the electric utilities are dedicated to studies of various methodologies to be employed in overcurrent protection. The objective of this study is to evaluate the overcurrent systems protection for medium voltage used by some of the major electric utilities in Brazil and make a relationship with their levels of performance and safety. The work begins with a basic presentation of electric utilities evaluated, the characterization of their distribution systems and medium voltage protection philosophies used. Then are presented the overcurrent protection equipment for medium voltage used by utilities and the principles to obtain an efficient coordination between the protection equipment. In the sequence the performance data of the concessionaires (DEC and FEC) are analyzed and compared with the characteristics of overcurrent protection systems. The analyzes showed that there is not a direct relationship between the performance indexes DEC and FEC and characteristics of overcurrent protection systems of the utilities. This suggests that, after specific studies, there concessionaires that can make their distribution networks more secure for the population, without compromising its performance indexes.