When a network incident occurs in an area of the electricity grid where a battery energy storage system (BESS) is available, an electrical island is activated and the BESS becomes responsible for maintaining its voltage and frequency. Once the network connection is restored, the operation of the BESS must be adjusted to synchronise the island voltage waveform with that of the main network without causing a service interruption. The grid-island synchronisation system installed by i-DE takes samples of the grid voltage at the primary substation and sends them to the BESS control system so that the island voltage can be synchronised and the reconnection can take place.
This system proved to be successful on multiple occasions, preventing the disconnection of generating plants from the grid and the interruption of customer service during the island-grid transition. Furthermore, the system can synchronise two independent BESS islands without disturbances, allowing the replacement of a single BESS installation with sets of smaller twin batteries.
