Grid interconnection device, grid interconnection system and transfer trip system

A transfer trip system comprising a power distributing substation and a grid interconnection system, which are connected to each other through a power distribution system, wherein

• the power distributing substation includes a transmitter configured to transmit, to the grid interconnection system, through a predetermined transmission path, power failure information containing at least local area information indicating an area in which a power failure occurs,
• the grid interconnection system comprises:
• a power generation device configured to generate power;
• a power conversion circuit configured to convert the power from the power generation device into predetermined alternating-power;
• a relay configured to switch between separation and interconnection of the power generation device to and from the power distribution system;
• a relay controller configured to control separation or interconnection of the relay;
• a receiver configured to receive, from the predetermined transmission path, the power failure information;
• a determination unit configured to determine an occurrence of a power failure in the power distribution system, when the power failure information includes local area information of an area to which the power distribution system belongs;
• and
• a detector configured to detect an islanding state;
• wherein
• the detector increases detection sensitivity of the islanding state when the determination unit determines the power failure occurs in the power distribution system;
• and
• the relay controller performs separation control for the relay when the islanding state is detected by the detector.