Smart Inverter Voltage Support Functions (Volt-Var and Volt-Watt) Testing
Richard John Bravo1, H. Walter Johnson2, Harby Sehmar3
1Southern California Edison, Westminster, CA, United States
/2Electric Power Research Institute, Palo Alto, CA, United States
/3Pacific Gas and Electric, San Ramon, CA, United States

The two main smart solar photovoltaic inverter (SI) functions responsible for providing grid voltage support under the revised California Rule 21 (CAR-21) and IEEE1547-2018, required as of September 2017, are voltage-reactive power (volt-VAr or VV) and voltage-real power (volt-watt or VW). This paper presents test results for these two SI functions. The SIs evaluated are from two different manufacturers and have been designed to operate in accordance with the revised CAR-21 that incorporated SI functions such as voltage ride-through, frequency ride-through, volt-VAr support, volt-watt support, frequency-watt support, and ramp rates. The primary reason for testing these SIs is to explore the performance of autonomous SI features that can help alleviate potential issues caused by high penetrations of these devices in the electric grid. First, this paper details the setup and the equipment used for this testing. It then presents the test results and analysis. Finally, it provides an overview of the potential grid benefits of these two functions when set properly and provides recommendations for SI settings when they are interconnected into the grid. The test data can be used for model development and validation to assess grid performance with a high penetration of SIs.

Area: Sub-Area 5.7: Performance Testing and Standards