Mobil-Grid-CoP: Mobile Test Facility for Grid-Compliance Testing

At a glance

• In an energy system which is essentially based on renewable energies, wind turbines must be capable of stabilizing the grid.
• As offshore wind turbines continue to grow in size, the current facilities for testing grid characteristics are being pushed to their limits.
• Within the scope of the Mobil-Grid-CoP research project, the Fraunhofer IWES will therefore be developing and operating a mobile grid emulator which is able to check the electrical properties of wind turbines as well as their capacity to support the  grid in the event of faults.

The challenge

The energy transition is in full swing. In place of conventional coal and nuclear power stations, wind farms and solar plants are becoming ever more responsible for our power supply. As a result, such systems must be able to provide the grid stability services which have been guaranteed by conventional power stations to date.

At the same time, the ever-increasing size of offshore wind turbines is pushing the current facilities for testing grid characteristics to their limits. Since the certification tests have an impact on the downstream power supply, the growing turbine size places greater demands on the connection of the fault ride through (FRT) container at the grid connection point (GCP). Given that a targeted change in grid frequency is not possible in the open field, the behavior of the power generating unit (PGU) in the case of grid frequency changes is currently tested by means of changing the parameters in the PGU control. 

The solution

The aim of the Mobil-Grid-CoP research project is thus to set up and operate a test facility to solve precisely these problems. Possibly this facility will enable measurement campaigns in order to obtain the unit certificate for wind turbines. Furthermore, it should also be able to perform tests to confirm the current and future requisite grid system services with only a very minimal retroactive effect on the downstream power supply.

The added value

To this end, the Mobil-Grid-CoP will be positioned between the grid connection point and the wind turbine to emulate an electrical grid. The turbine’s reaction to dynamic changes in voltage, voltage support in the event of failures, and the impact on the overall system can all be examined.

It is expected that the grid emulator will start operating in winter 2023.