The rapid increase of decentralized, variable renewable energy (RE) sources such as solar photovoltaic (PV) and wind in the electric power grid is offsetting the traditional, centralized electricity generation. Decentralized solar PV and wind are a few examples of distributed energy resources (DERs) that are mostly inverter-based and they influence power system operations and dynamics. Grid codes or interconnection standards around the world are getting updated to include grid-support functions and interoperability requirements for DER devices. These functions provide utility operators with new methods for voltage regulation, bulk system control, power system visibility, and other grid services. However, DER vendors, grid operators, certification laboratories, and academic smart grid test laboratories need the ability to verify these new functionalities to ensure effective communication and power characteristics. Validating device behaviors for a range of conditions and corner cases accelerates the deployment of these novel RE technologies by providing confidence the equipment will work to operate a safer and resilient grid as power systems evolve.
The ultimate goals of this working group are to create consensus interoperability testing protocols and test platform software that will contribute to the implementation of harmonized, international certification standard for any DER on any electricity grid in the world, as well as the tools that will facilitate automation of the testing, thus reducing a major barrier to test implementation. In November 2013, Sandia published a set of test protocols in the report SAND2013-9880 Test Protocols for Advanced Inverter Interoperability Functions. These test protocols became the basis for the development of certification standards for advanced PV inverters and other DER devices for many national and international standard development organizations such as UL, IEC, IEEE, CSA, etc. This report also became a stepping-stone for the Smart Grid International Research Facility Network (SIRFN) in developing and evaluating testing protocols for advanced interoperability DER functions as well as scripts and other tools that allow the automation of testing procedures. The goals of this work are (a) to collaborate with standard development organizations to create consensus interoperability testing protocols and (b) write an open-source test platform software that will accelerate the certification process, and reduce time and human errors in test implementation.
The SIRFN collaboration work has created a versatile, open-source DER certification platform and associated test scripts for multiple certification standards. This platform allows test automation and is known as SunSpec System Validation Platform (SVP). The SIRFN laboratories are all contributing to an open-source repository of software tools that control laboratory equipment to orchestrate DER interconnection and interoperability certification standard testing. The generic testbed architecture as used by the SIRFN laboratories is shown below in the figure. Laboratories including CanmetENERGY (Canada), Sandia National Laboratories (USA), AIT (Austria), FREA (Japan), KERI (Korea), and CSIRO (Australia) are performing UL 1741 SA, IEEE 1547.1, and other test protocol tests using SIRFN-developed SVP scripts on residential inverters. The test labs are exchanging technical information on the design and operation of the advanced DER test beds and software for executing interoperability testing and comparing results for different DER sizes and designs on grids with different frequencies and voltages. This has enabled the SIRFN group to continuously assess the versatility and effectiveness of upcoming grid codes and associated test procedures from different jurisdictions and provide feedback to the standards development organizations for corrections and enhancements of the test procedures.
Automated testbed with open source system validation platform software (Sunspec SVP)
The SIRFN group is also currently working on enhancing the capability of the test platform for new features, e.g., report generation, real-time plotting, etc. Ultimately this package, which includes an open-source software tool, test cases and procedures, will target the full spectrum of the industry from DER vendors, universities, research institutions, certification laboratories and standards organizations to apply the same codified testing methods at each stage of development. This provides DER vendors with confidence that their equipment will pass certification tests and grid operators with confidence the equipment will function correctly on the power system. In addition, with public, software-driven, conformance test procedures, DER manufacturers can quickly and easily certify their products to different grid codes and gain access to multiple markets. These standardized DER capabilities will pave the way towards full integration of RE and battery systems into future smart grid control schemes. Eventually, this will permit utility and grid operators to manage thousands of DERs in a unified way and facilitate more renewable energy on the electric power system.
The SIRFN work will improve the test procedures and incorporate them in national and international standards by:
- Building test beds for advanced interoperability DER testing in SIRFN laboratories
- Coordinating the experimental testing of DER devices in the Americas, Europe, Australia and Asia to ensure the protocols are robust to a range of electric grids and test equipment
- Continuing execution of automated DER interoperability certification tests using a common open-source software tool, including development of recommendations to standards
- Revising the test protocols to prepare for adoption by code-making bodies
- Sharing, comparing and analyzing the test results of multiple labs with the different setups for verifying common test protocol
- Sharing knowledge through internal and external workshop/webinar and publications to build external awareness of group activities
- Create DER certification testbeds
The SIRFN research laboratories are contributing to an open-source repository of software tools (OpenSVP) that control laboratory equipment to orchestrate DER interconnection and interoperability certification standards testing. As each lab contributes to the collection of equipment/device drivers, the collection of software tools becomes more comprehensive and there is a lower barrier to begin this type of work for the following/new laboratories.
- Create Certification Scripts
The group has developed test scripts for the Sandia test protocol, UL 1741 and IEEE 1547.1 standards. The SIRFN laboratories are currently contributing to create additional IEEE 1547.1 Python scripts for the SVP. In addition, the group has initiated development of scripts for the Australian standard, DR AS/NZS 4777.2, as the standard became available for public review. The group will also initiate development of test scripts for draft grid codes from Asia and Europe as they are completed.
- Conduct Certification Testing at SIRFN Laboratories
The SIRFN laboratories will conduct IEEE 1547.1 and AS/NZS 4777.2 tests using the open-source test platform and developed test scripts. The conducted tests and compiled test results will allow the laboratories to provide feedback to the respective standards development organization to improve further their standard before formal adoption. The group will also conduct testing for other upcoming grid codes from different jurisdictions and will provide feedback to the associated working groups.
CanmetENERGY, Natural Resources Canada (NRCan)