Remote Micro-Grid Synchronization Without Measurements at the Point of Common Coupling

This article presents a new strategy of active synchronization of an island micro-grid and the utility grid (UG) without measurements at the point of common coupling (PCC). This strategy is based on the assistance of Ethernet communication, GPS pulse-per-second device synchronization, and droop control parameter shift. A strategy with Ethernet-assisted synchronization is used instead of synchronization with dedicated low-bandwidth communication. This strategy is based on exchanging data between two proposed devices: synchronization data sender (SDS) and synchronization data controller (SDC). The SDS calculates the UG voltage parameters and sends these data to the SDC device. The SDC is responsible for receiving synchronization data and calculating droop control parameter shift. The use of GPS-based device synchronization adds very stable and accurate measurements of synchronization parameters that correspond to the stable synchronization signal. As this strategy uses droop control method parameter change, all distributed generators share loads adequately. This strategy introduces the possibility to remove the need for measurement of voltage directly on the switch location. The proposed devices could be connected even a long distance from the PCC. The strategy also introduces the possibility of working in synchronism with the main grid despite the island mode of the micro-grid. This introduces the possibility to connect the micro-grid at the same moment as fault clear or maintenance end.