Keynote Title - Grid-Forming: A New Operating Philosophy for Distributed Power Systems

Abstract: Power systems are entering a new operational era. For more than a century, electrical grids were built around synchronous machines, whose physical behaviour naturally shaped voltage, frequency, inertia, fault response and system strength. During the last decades, however, this foundation has been progressively replaced by inverter-based resources: wind and photovoltaic plants, battery storage systems, HVDC links, STATCOMs, electric vehicles and power-electronic loads. The result is not only a technological transition, but a profound change in the way power systems must be designed, certified, operated and protected. In this context, grid-forming converters are often presented as a new family of control strategies. This keynote will argue that they are much more than that. Grid-forming is becoming a new operating philosophy for renewable-dominated power systems. It changes the role of the converter from a device that follows an existing grid to an active element that helps create, support and stabilise the grid itself. Instead of behaving only as controlled current sources connected to a strong external voltage, converters are now expected to act more like voltage-forming assets, capable of contributing to frequency, voltage, synchronisation, damping, restoration and system resilience. This shift raises fundamental questions for industry. How should manufacturers design converters that are no longer only compliant devices, but active grid-supporting assets? How should certification evolve after decades of testing converters mainly under grid-following assumptions? What does it mean to validate a grid-forming plant, not just an individual converter? How should plant integrators combine grid-forming units, grid-following units, storage, renewable generation and plant-level controllers into a coherent system? And how will operators specify, procure and trust these capabilities in real networks? The keynote will discuss the opportunities opened by this transition. Grid-forming converters can support weak grids, enable higher renewable penetration, improve microgrid operation, assist black start and restoration, strengthen HVDC and hybrid AC–DC systems, and provide new forms of fast dynamic grid support. At the same time, they challenge existing practices in protection, fault ride-through, current limitation, interaction studies, compliance testing and system planning. Rather than focusing on control diagrams, this talk will place grid-forming technology in its broader industrial and system context. It will explore why system operators are increasingly interested, why converter manufacturers are adapting their portfolios, why renewable plant developers need new integration methods, and why grid-forming may become one of the defining technologies of the next generation of power systems. The central message is simple: grid-forming is not just about making converters behave like machines. It is about deciding how future power systems will operate when machines are no longer the natural reference.