First Grid-Forming 300 MVAr STATCOM in Germany

Amprion’s STATCOM Opladen project addresses future grid stability challenges with reactive power support and grid-forming control. It operates nearly independently of short-circuit power levels, ensuring a stable 400 kV grid under a variety of scenarios. The project sets the foundation for future grid-forming solutions and contributes to the safe and robust integration of renewables into the transmission grid.

Highlights

• First extra-high voltage grid-forming STATCOM: Previously only tested on smaller scales, now applied in Europe’s 400 kV grid.
• Successfully operating since August 2023, ensuring stability during system splits and scenarios where the grid’s short-circuit power is reduced.
• Amprion plans to implement 5-9 additional STATCOMs with storage to meet future system demands.

About this Practice

The STATCOM Opladen project is a significant technological achievement aimed at improving grid stability in Germany’s 400 kV transmission network. With the increasing reliance on renewable energy sources, the power grid faces the challenge of maintaining stability in a changing energy system with longer transmission distances and less conventional power plants. Amprion partnered with Hitachi Energy to develop a 300 MVAr STATCOM equipped with reactive power support and grid-forming (GFM) control. This technology is mainly used for voltage control and support during severe grid disturbances.

The primary goal of this project was to ensure the system’s stability, even in scenarios where the grid experiences a drastic reduction in short-circuit power. Traditional grid-following systems struggle to maintain operation under such conditions, but grid-forming control ensures the STATCOM can function effectively even at low short-circuit levels. 

During the development phase, various scenarios were tested, including angle and amplitude jumps in voltage and changes in grid short-circuit ratios. The grid-forming control demonstrated an inherent response to amplitude changes and provided immediate stabilisation during angular shifts. These results confirmed the system’s capability to enable grid-forming control without oversizing its components.

This project, which began operation in August 2023, marks the first large-scale implementation of grid-forming converter controls in the European extra-high voltage grid. Amprion plans to enhance the technology by incorporating energy storage systems in future STATCOMs to provide inertia and further stabilise system frequency during severe disturbances. 

This innovation not only addresses current grid stability challenges but also lays the groundwork for long-term, scalable solutions essential for the evolving energy landscape. Amprion’s commitment to continuous improvement will see the installation of additional units to meet the increasing demands for grid-forming capabilities.