Objectives

• demonstrate the advanced grid support functionalities of smart inverters
• evaluate the impact of smart inverter voltage regulation functions on distribution circuit voltage

Summary

To achieve high penetration of distributed energy resources (DER) in distribution systems, inverters need to become utility assets rather than just continuing to be negative loads relative to the feeder and end user facilities. DERs are limited in their practical application due to the restrictions imposed by existing standards and practices that were designed with low-penetration levels in mind. The aim of this project was to evaluate and demonstrate the functionalities offered by smart inverters and apply them into a grid connected PV system. The desired results were increase the understanding of how to deploy and utilize distributed PV systems more effectively.

The project demonstrated how distributed PV systems can provide grid functionality through the application of smart inverters. The advanced functions desired from these distributed resources included the following:

• autonomous and scheduled volt-VAR support for point-of-coupling active voltage regulation
• fault ride through to stay online during the transient grid disturbances like sags and swells
• extended operating voltage and frequency ranges to avoid nuisance tripping
• ability to act on utility commands for connect/disconnect and real power curtailment through maximum generation level setting for distribution system asset protection

The project modeled and analyzed a feeder and demonstration site to show the affects of adding new functionalities and the potential to increase the penetration levels of DER on a feeder. Pre- and post-demonstration feeder simulations and analysis validated the system reliability and quantified the benefits of PV inverters with smart-grid functionalities for the specific location.