GRID-OFF MICROGRID SYSTEM CAPABLE OF MAINTAINING RATED VOLTAGE AND RATED FREQUENCY

摘要

Provided is a grid-off microgrid system capable of maintaining and controlling rated voltage and rated frequency. More specifically, the grid-off microgrid system comprises: a microgrid including an energy storage device (ESS) which contains a battery and at least one distributed power source which acquires renewable energy to supply power to at least one load; a power converting device converting power of the distributed power source and the ESS; and a central control unit forming a point of common coupling (PCC) for an interface between the ESS and the distributed power source, and controlling a voltage and frequency of the microgrid to maintain the voltage and frequency to be a rated voltage and a rated frequency in real time. The central control unit controls the voltage of the microgrid by using the reactive power of the power converting device, and controls the frequency by using the active power of the power converting device.