F-HIL RELOADED - Development of a test infrastructure for the normative validation of dynamic processes of grid-forming decentralized energy ressources

Ensuring a secure energy supply with the increasing use of volatile energy sources and flexible consumers is already a challenge for distribution grid operators today. Due to the further expansion of decentralized wind energy and photovoltaic systems and the simultaneous dismantling of central power plants, the new decentralized generation units must now take over the stabilizing functions in the electricity grid.

In future, this can be achieved by designing and controlling the electronic power converters through which the decentralized generation units are connected to the grid. Such grid-forming power converters are able to stabilize the voltage amplitude and frequency. They are therefore an important component of a secure and stable energy supply in the future.

The development of suitable test sequences and corresponding guidelines for grid-forming systems is an important component that is currently receiving little attention. In-depth testing of grid-forming functions and the interoperability of power converters, i.e. their interaction with a wide range of other grid components, is essential in the course of an exclusive energy supply from renewable energy sources.

From the point of view of the VDE Grid Technology/Grid Operation Forum, the requirements for generation plants with regard to the stability of the interconnected grid are currently not sufficient and additional system-supporting or grid-forming capabilities and functions for generation plants must be defined, as the recently published System Stability Roadmap makes clear. The “F-HiL Reloaded” project is dedicated to these challenges and promotes the development of innovative inspection and test systems with the associated test procedures and test specimens, such as grid-forming DC wall boxes for electric vehicles.

The test, verification and validation system shown in the following figure is realized as a combination of a real-time computer, a dynamic hybrid amplifier unit and an adjustable line impedance for the realistic simulation of grid conditions (e.g. grid impedance, weak or strong grid connection). To quantify the project results, DC wallboxes for bidirectional electric vehicles in charging and discharging mode and rapid control prototyping systems (RCP) with the corresponding grid-forming properties and controls are planned as test specimens.