No Inverter Left Behind: Protection, Controls, and Testing for High Penetrations of PV Inverters on Distribution Systems

Utility control and generation dispatching are integral parts of enabling high penetrations of PVs on distribution systems. The control and communication features of smart inverters will provide utilities with additional flexibility and the capabilities to introduce new mitigation solutions to properly utilize distribution assets and accommodate increases in renewable resources. Smart inverter capabilities are, however, in an early stage of development and require investigation, evaluation, and testing to characterize the features offered and determine exactly how they respond to system events such as voltage variations, faults, and islanding. In addition, inverter features and requirements need to be customized to match utilities' interconnection requirements, as well as existing or planned distribution system automation and operational aspects. Although the aim is to achieve standard control and communication features, many aspects of deploying controls, optimizing schemes and settings, and integrating inverters into utility communication architectures will be utility-specific for now. These processes will require coordination with existing infrastructure if they are to accommodate specific utility practices. Advanced testing methods, such as PHIL using a real-time simulation test setup, can help accurately characterize the dynamic behavior of PV inverters as they interact with the distribution grid.