Patent ID: 11916389
Assignee: DAIHEN CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  B  Y | IPC B  H

Claim 7:
8. A grid interconnection method for a power grid, comprising:
by using a storage battery and a power conversion device for converting power from the storage battery into AC, supplying power from a commercial power supply to a load;
supplying power from the power conversion device to the load when the commercial power supply fails;
causing the power conversion device to synchronize a voltage phase of power supplied from the power conversion device to the load with a voltage phase of power from the commercial power supply when the commercial power supply is restored;
starting supply of power from the commercial power supply to the load after the voltage phase of the power supplied from the power conversion device to the load is synchronized with the voltage phase of the power from the commercial power supply; and
stopping the supply of power from the power conversion device to the load after the supply of power from the commercial power supply to the load is started,
wherein, determining whether or not a voltage and a frequency of the power from the commercial power supply are within a predetermined range,
when the voltage and the frequency are within the predetermined range, synchronizing the voltage phase of the power supplied from the power conversion device to the load with the voltage phase of the power from the commercial power supply, and
when the voltage or the frequency is not within the predetermined range, waiting for a process for phase synchronization and continues supply of power to the load.