With the adoption of IEEE 1547-2018 at Duke Energy, the utility discovered that exploring the use of smart inverter functions (volt/VAR, volt/watt, watt/VAR) within DER facilities to perform distribution system voltage regulation is a complex initiative. Duke Energy operates all DER facilities connected to the distribution system at constant power factor, typically unity, which in certain situations has constrained interconnection. To potentially address these issues, Duke Energy implemented a pilot program with a select number of DER facilities to explore different avenues for utilizing these functions.

These functions come with design requirements for DER facilities that were traditionally not required for an interconnection approval. In addition, outside of the DER facilities themselves, no two points of interconnection on the grid have the same electrical characteristics and customer tailor must be performed to evaluate options and settings. Lastly, utilities typically already have a number of existing initiatives in place to manage voltage on the distribution system. This creates a multi-variable problem that requires careful consideration to ensure all the pieces fit together cohesively.

This session will explain the site selection criteria used to find viable pilot candidates, the development of the methodology Duke Energy implemented for designing site specific smart inverter settings to accomplish adequate voltage regulation, the impact that such functionality has had on the existing voltage regulation schemes in place on the distribution system, and an overall summary of the performance of the pilot DER facilities. This session could help any utility that has not yet embarked down this path by providing a perspective that might help identify a starting point and lay the groundwork needed to begin the pilot project.

Attendees will leave with an understanding of the engineering basis for selecting and studying candidates to use smart inverter functions, a business perspective on introducing this as a process change, and an introduction to the long-term complexities of monitoring and enforcing these facilities to ensure operational characteristics don't change.