Grid Forming Inverters for Storage Systems

In today’s power grid the grid forming, which means the control of the grid voltage with a stable amplitude and frequency, is provided mainly by conventional power plants. As a result of the substitution of these power plants by power-electronically coupled renewable generation units and storage systems this system service must be taken over by these systems.
At Fraunhofer ISE we develop new control algorithms which are bringing these “grid forming” characteristics to inverters. We analyze the stability of devices with network-forming properties in a wide variety of network states and environments and optimize the corresponding algorithms and their parameterization.
Moreover we develop and optimize the hardware solutions for inverters with grid forming functionalities. For the optimal specification and integration of grid forming inverters into the power grid, we perform grid integration studies.
In our Multi-Megawatt Lab in Freiburg, we offer the metrological verification of the network-forming properties by means of specially developed measuring methods for test objects down to the multi-megawatt range. Our facilities allow us to prove the FRT capabilities and their contribution of grid-forming devices to the system inertia. Furthermore we analyze their effect on the power quality and the harmonic stability.