Management of a multiple-set synchronous island

The continuity of power supply can be improved by power system islanding. A possible solution, synchronous islanded operation, enables the islanded system to remain in phase with the main power system while not electrically connected, and so avoids out-of-synchronism re-closure. Specific consideration is required for the multiple-set scenario, and is the topic of this paper. A suitable island management system is proposed, with the emphasis being on maximum island flexibility by allowing passive islanding transitions to occur, facilitated by autonomous control. These transitions include: island detection, identification, fragmentation, merging and return-to-mains. It can be challenging to detect these transitions while maintaining synchronous islanded operation. A Mathworks SimPowerSystems simulation is used to investigate the performance of the island management system. However, return-to-mains is particularly difficult to detect, and so a method based on voltage phase angle variability is explored by using a laboratory demonstration and time stamped phasor measurements.