by: Debjyoti Chatterjee and Pranjal Gajare
The UNIFI General Meeting, held from July 22–24, 2025, at the University of Wisconsin–Madison, brought together researchers, industry experts, and system operators to share research updates and discuss future directions for accelerating the integration of grid-forming (GFM) inverters into power systems. The gathering was graciously hosted by Dr. Dominic Gross. With power systems undergoing a rapid transition due to the evolving nature of generation and loads, discussions focused on the standardization process and on expanding the reach of GFM technology to make its adoption easier and more scalable.
The meeting opened with an overview of UNIFI’s key accomplishments and a high-level plan for developing future specifications and standards for GFM technologies. The modeling group presented updates on the new REGFM models, developed in collaboration with industry experts, and highlighted challenges in tuning requirements for inverter-based resources.
Another major theme was GFM inverter performance under various constraints, such as current limits and DC-side limitations, and how these interact with existing power system protection schemes. The impact of emerging loads such as data centers and the potential value of GFM inverters in mitigating these impacts also received significant attention. System operators and researchers emphasized the need for new metrics to guide interconnection studies before moving to EMT simulations.
The meeting featured several lively panel discussions. A session on IBR protection, led by experts from ASU, GE Vernova, NREL, and EPRI, examined evolving protection needs in inverter-dominated systems. Another panel explored resource dynamics and DC transmission, with speakers from GE Vernova, ABB, Eaton, Ingeteam, Siemens Energy, and Grid United, who discussed how these technologies shape GFM operations. During the Q&A sessions, several important points surfaced: requirements from operators vary significantly across countries; while synchronous generator dynamics are fixed, GFM dynamics are programmable, raising questions about how many parameters OEMs will be expected to tune; concerns that excessive standardization could stifle innovation; and the urgent need for guidance or a white paper to support protection engineers. Together, these panels provided a broad view of both technical and operational priorities, bridging academic insights with industry practice.
Discussions on standardization pathways built on momentum from the previous meeting. During this meeting, different tiers of GFM inverters are introduced based on frequency-domain specifications. A major proposal was to incorporate the latest UNIFI specifications into IEEE 2800, the foundational standard for grid-connected inverters. Alongside this, participants debated whether performance requirements should be defined at the device level or at the plant level. The consensus was that certain specifications must apply at the plant level and others at the unit level—the key challenge is deciding how to divide them. Participants stressed that it is not about choosing one or the other, but about finding the right balance between plant-level coordination and unit-level performance.
A highlight of the meeting was an update on the 1 MW multi-vendor grid-forming integration experiment at NREL, where different inverter platforms were operated together to evaluate interoperability and dynamic performance. Specific investigations included the implementation of negative-sequence controllers, comparison of fault responses across five different OEMs’ GFM inverters to assess IEEE 2800 compliance, and the impact of GFM fault behavior on protection relays.
Participants were also introduced to a new “GFM Around the World” dashboard, now available on the UNIFI website. This interactive tool compiles and visualizes global efforts on grid-forming inverter research, demonstration projects, and deployments, offering the community a centralized resource to track progress and share knowledge.
The Crosscut Testbed (CCT5) team shared updates on the design of comprehensive GFM testbeds. The initiative aims to enable rigorous validation of inverter-based resource performance under a wide range of operating conditions, providing a foundation for both technical advancement and future standards development.
The 2025 UNIFI General Meeting concluded with an engaging open-ended discussion on the R&D needs for grid-forming inverters and how UNIFI can best support the community in addressing them. Participants highlighted the importance of developing a software testbed that closely mirrors real-world systems. Other key questions included how GFM technologies could support the rapidly growing demand from data centers, how to better characterize the grid services GFMs can provide, and how to ensure appropriate compensation for those services. This forward-looking dialogue emphasized the critical role UNIFI can play in aligning research, standards, and practical deployment.
Beyond technical sessions, students had unique opportunities to engage with industry members. Over informal networking event across Lake Mendota, they exchanged ideas, fostered connections, and explored potential future collaborations. Participants also enjoyed a visit to the Wisconsin State Capitol.
The event concluded with guided tours of UW–Madison’s Power Electronics and Power Systems laboratories, where faculty and graduate students showcased ongoing experimental research supporting UNIFI’s mission.
The students’ poster session featured research from across the UNIFI community, and three students were recognized for their outstanding research contributions: Dahlia Saba (UW–Madison), Prajwal Bhagwat (UW–Madison), and Pranjal Gajare (Georgia Tech).
