On Stability, Ancillary Services, Operation, and Security of Smart Inverters

This paper presents some recent trends in the research of grid-interactive inverters. Particularly, this paper focuses on stability, ancillary services, operation, and security of single and multiple inverters in the modern power grid. A grid-interactive inverter performs as a controllable interface between the distributed energy sources and the power grid. High-penetration of inverters in a power distribution system can create some technical challenges on the power quality, as well as voltage and frequency control of the system. In particular, a weak grid can lead to voltage oscillation and consequently instability. Moreover, the power grid is moving toward becoming a cyber-physical system in which smart inverters can exchange information for power marketing and economic dispatching. This puts the inverters at the risk of insecure operations. Hence, security enhancement has become another primary concern. Finally, the grid-interactive inverters are operated proportional power-sharing while operating together with many inverters. Recent research on coordinated operations is also discussed in this paper.