As utilities have started to depend on distributed energy resources (DERs) for power system reliability, it is critical to identify any error or discrepancy in the as-built plant against the approved design and performance requirements.

Commissioning tests (a.k.a. witness tests) are often required by the utility as the last step before a DER receives permission to operate. The purpose of these tests is to confirm that the complete system as designed, built, and configured meets the interconnection and interoperability requirements. As utilities are adopting the IEEE Standard 1547-2018, commissioning tests are becoming increasingly important to ensure as-built plants conform with the interconnection and interoperability requirements, which in turn, promotes safer and more reliable distribution operations.

Commissioning test practices are currently in varying stages of maturity as the quantity of DERs rises and inverter-based DERs are becoming more common. As utilities adopt IEEE 1547-2018 DER interconnection performance requirements, their commissioning practices may need to be updated and/or expanded.

This panel will discuss the "why's," "what's," and "how's" of conducting commissioning tests for conformity assessment. Panelists including engineers from multiple utilities — Salt River Project, FirstEnergy, and ENMAX Power Corporation — and EPRI staff will share their perspectives, real-world field experiences, lessons learned, and identified best practices to confirm the correct installation and configuration of the DER plant.