Coordinated control for isolated distribution networks supplied by inverter power sources

New energy generation systems, such as photovoltaic cells or fuel cells are increasing in application on distribution networks. These power sources require an inverter to connect to an AC network. There is the possibility that sub-network containing inverter power sources will be disconnected from the utility system to become isolated networks. This paper focuses on an isolated distribution network supplied by inverter power sources without the use of a synchronous generator, and proposes coordinated control for the inverters. The feature of inverter control is that one inverter has constant frequency characteristics and the other inverters are operated by constant active power control. The coordinated control is demonstrated by digital simulation.