Frequency-Supporting Control of a Solid-State Transformer

The decreasing system inertia of power systems, due to the increasing number of power-electronic-interfaced units, can lead to frequency stability issues. Usually, when it comes to frequency-supporting control algorithms, only power-electronic generation units are considered. However, in this paper, a load control for a solid-state transformer is introduced, which provides frequency support to the grid. Moreover, the German grid will be modeled using the common governor-turbine-generator model and an estimated system inertia will be derived. Furthermore, the solid-state transformer control will be tested and compared to the conventional control using the derived grid model within a Simulink/PLECS simulation environment. Lastly, the control is implemented and tested in a laboratory setup.