Automating the Sandia Advanced Interoperability Test Protocols

As the penetration of non-dispatchable renewable energy increases around the world, there is greater need to have smart power electronics interfaces to stabilize the electricity grid. Distributed Energy Resources (DERs) with advanced grid functionality and utility communication capabilities have the ability to assist grid operators with frequency and voltage regulation. As a result, the California Public Utilities Commission (CPUC) is considering updating Electric Rule 21 to require advanced functions on all newly interconnected PV inverters for Investor Owned Utilities (IOUs). One hurdle to installing PV inverters with the new functionality is certifying the DERs for advanced interoperability grid functionality defined in the International Electrotechnical Commission (IEC) Technical Report 61850-90-7. In November 2013, Sandia National Laboratories published testing protocols for advanced grid functions as a precursor to an international or updated Underwriters Laboratories (UL) 1741 certification standard. To accelerate this process, Sandia and an international collaborative of research laboratories began exercising the test protocols to improve the procedure and test parameters for the different advanced functions. This paper describes the process of automating the testing process with the SunSpec Alliance System Validation Platform and python scripting methodology. Results from four automated interoperability functions for a 3 kW residential-scale photovoltaic inverter are included. Index Terms — advanced inverter functionality, advanced grid functions, smart grid, voltage support, frequency support, photovoltaic systems, PV reliability.