Making isolated renewable energy systems more reliable

A hybrid renewable energy system (HRES) uses several kinds of sources, including wind and solar, to make better use of the natural resources in standalone applications. A common application of HRES is in remote communities, where interconnected electrical grid is unreachable due to economics and physical reasons. Due to the long distance and difficult access to these isolated areas, electrical generation systems used in these applications must be reliable. And the reliability of the system, especially the inverter used to regulate the AC voltage, is one of the main problems associated to these systems, and it is responsible for the lack of confidence in renewable systems at several locations in Brazil. This paper shows the results of using renewable hybrid systems specially designed for isolated areas, focusing attention on reliability, efficiency and expansion flexibility. It presents the system description, mode of operation, inverter design, and experimental results measured in a pilot plant located in Lençóis Island, a small isolated community in the north region of Brazil.