Power Management and Control for Grid-Connected DGs With Intentional Islanding Operation of Inverter

This paper describes a power management method in a feeder with distributed generations (DGs) and energy storage devices. To ensure stability, reliability, and safety of the system, the proposed power management method deals with the DGs in two groups, which are utility and independent power producer (IPP). When the feeder is islanded from grid, the utility-owned DG receives fault signal from the protection relay. Thereafter, it is allowed to operate itself when the feeder is islanded because it is directly controlled by the utility. In contrast, the IPP-owned DG should be stopped to avoid several problems, which can be caused by the islanding operation. Then, the proposed power management method operates the above DGs to maximize the efficiency with no serious impact to grid. To do so, the inverter controller of DG is designed to implement it in a part of practical distribution system, which is located at the Do-gok area in Seoul, Korea. Several case studies are carried out to verify the effectiveness of proposed method.