Safe controlled islanding of inverter based distributed generation

When the power utility is subjected to a disturbance and part of the distribution system is approaching catastrophic failure, control actions need to be taken to limit the extent of the disturbance on the critical customers. An effective approach to secure power supply for the most important customers is by implementing safe controlled islands (SCI) in the distribution system during a utility outage. The ultimate goal when such a scheme is implemented is maintaining the voltage and frequency during islanded operation within the standard limits. This paper presents a novel control strategy to produce SCI with particular reference to inverter interfaced distributed generators (DGs).