Planned islanding for Brazilian system reliability

This paper presents an impact study case of a new operational strategy regarding planned islanding operation of distributed generation. Traditionally, interconnection standards avoid islanding operation of distributed generation due to the concerns of equipment failure and safety issues. However, allowing the islanded operation of distributed generation may enhance reliability to final consumers and decrease outage cost by providing an alternative power source when there is an interruption in the upstream network. This paper performs dynamic studies in a Brazilian system which operates in the islanded mode during fault to supply critical loads. The analysis presented in this paper includes the behavior of the islanded system under load following and load rejection, faults, the load-frequency control and varying short-circuit level. The results show that this operational strategy can potentially bring many benefits to the distributed generator owner and customers.