Case Study: Interoperability of Two Independently Designed Grid-forming Converters

Grid-forming converters have been identified as a crucial element in enabling the stable operation of future power grids with a significant proportion of converter-based resources. As grid-forming assets are planned for installation at all voltage levels, it will be necessary to operate multiple devices in parallel without undesirable interactions. Consequently, it is essential to conduct studies to assess the interoperability of grid-forming converters, with the aim of identifying critical scenarios and to establish procedures aimed at preventing unwanted interactions. This experimental study investigates the interoperability of two independently designed grid-forming converters, focusing on parallel operation within a small island grid. The results demonstrate that the two converters can operate together effectively. This is contingent upon maintaining both converters' operating points below their respective limits and ensuring sufficient decoupling. Furthermore, the conducted experiments reveal significant interaction between the converters, particularly when operating in current-limiting mode, underscoring the necessity for coordinated control strategies. The findings highlight both the potential and challenges of integrating grid-forming converters from different manufacturers, paving the way for further research on their functionality in diverse operational scenarios.